Inhaled Prostacyclin on Exercise Echocardiographic Cardiac Function in Preserved Ejection Fraction Heart Failure
01-02-2020 – HUANG, CHEN-YU; LEE, JEN-KUANG; CHEN, ZHENG-WEI; CHENG, JEN-FANG; CHEN, SSU-YUAN; LIN, LIAN-YU; WU, CHO-KAI
Purpose Treatments that improve outcomes in patients with heart failure with reduced ejection fraction (HFr
EF) have shown no benefits for those with heart failure with preserved ejection fraction (HFp
EF). Our study aimed to investigate the effect of inhaled iloprost on myocardial performance during exercise in HFp
Methods The study participants were enrolled from the ILO-HOPE trial (NCT03620526), a prospective randomized, double-blind, placebo-controlled study that was designed to investigate the effects of iloprost on cardiovascular hemodynamics during exercise in patients with HFp
EF. Subjects were randomized 1:1 to inhalation of iloprost or placebo for 5 min. Two-dimensional transthoracic echocardiography with high temporal resolution was implemented to measure left ventricular (LV) longitudinal strain, LV diastolic function, and RV function both at rest and during supine exercise at 20-W workload.
Results LV global longitudinal strain (GLS) in response to exercise increased more in the iloprost group (LV GLS, −24.96 ± 1.20 vs −20.75 ± 3.00, P < 0.001). Iloprost also resulted in greater increment of LV GLS during exercise (ΔLV GLS, +6.02 ± 1.39 vs +3.44 ± 0.80, P < 0.001). Moreover, iloprost use was associated with enhancement of LV diastolic function, RV systolic function, and relief of pulmonary hypertension during exercise.
Conclusions In patients with HFp
EF, inhaled iloprost favorably improved myocardial performance during exercise by increasing LV GLS reserve, decreasing LV diastolic filling load, and reducing stress-induced pulmonary hypertension and thereby improving RV systolic function. Larger studies are needed to validate the result and long-term benefits of iloprost in patients with HFp
“Chemotherapy-periodized” Exercise to Accommodate for Cyclical Variation in Fatigue
01-02-2020 – KIRKHAM, AMY A.; BLAND, KELCEY A.; ZUCKER, DAVID S.; BOVARD, JOSHUA; SHENKIER, TAMARA; MCKENZIE, DONALD C.; DAVIS, MARGOT K.; GELMON, KAREN A.; CAMPBELL, KRISTIN L.
Purpose The purpose of this study was to provide a rationale for “chemotherapy-periodized” exercise by characterizing cyclical variations in fatigue and exercise response across a chemotherapy cycle and comparing exercise adherence during chemotherapy between a prescription that is periodized according to chemotherapy cycle length and a standard linearly progressed prescription.
Methods Women with breast cancer who were prescribed taxane-based chemotherapy were randomly assigned to a supervised aerobic and resistance exercise program after a chemotherapy-periodized exercise prescription (n = 12) or to usual care during chemotherapy (n = 15). Fatigue and steady state exercise responses were assessed in both groups before the first taxane treatment and across the third treatment (i.e., 0–3 d prior and 3–5 d after the third treatment, and 0–3 d before the fourth treatment) to assess cyclical variations. Adherence to the chemotherapy-periodized exercise prescription was compared with adherence to a standard linear prescription from a prior study in a similar population (n = 51).
Results Fatigue increased from baseline (marginal mean ± standard error: 3.2 ± 0.4) to before the third treatment (4.1 ± 0.4, P = 0.025), then peaked at 3 to 5 d after the third treatment (5.1 ± 0.4, P = 0.001), before recovering before the fourth treatment (4.3 ± 0.5, P = 0.021). The peak in fatigue at 3 to 5 d post–third treatment corresponded to a decrease in steady state exercise oxygen consumption (V˙O2) (P = 0.013). Compared with a standard linear exercise prescription during chemotherapy, a chemotherapy-periodized exercise prescription resulted in higher attendance during the week after chemotherapy (57% ± 30% vs 77% ± 28%, P = 0.04) and overall attendance (63% + 25% vs 78% ± 23%, P = 0.05).
Conclusions Fatigue and exercise V˙O2 vary across a chemotherapy cycle. A chemotherapy-periodized exercise prescription that accommodates cyclical variations in fatigue may increase adherence to supervised exercise.
Unsupervised Isometric Exercise versus Wait-and-See for Lateral Elbow Tendinopathy
01-02-2020 – VUVAN, VIANA; VICENZINO, BILL; MELLOR, REBECCA; HEALES, LUKE JAMES; COOMBES, BROOKE KAYE
Purpose This study aimed to investigate the effect of unsupervised isometric exercise compared with a wait-and-see approach on pain, disability, global improvement, and pain-free grip strength in individuals with lateral elbow tendinopathy.
Methods Forty participants with unilateral lateral elbow tendinopathy of at least 6 wk duration were randomized to either wait-and-see (n = 19) or a single supervised instruction session by a physiotherapist, followed by an 8-wk unsupervised daily program of progressive isometric exercise (n = 21). Primary outcomes were Patient-Rated Tennis Elbow Evaluation, global rating of change on a six-point scale (dichotomized to success and no success) and pain-free grip strength at 8 wk. Secondary outcomes were resting and worst pain on an 11-point numerical rating scale, and thermal and pressure pain thresholds as a measure of pain sensitivity.
Results Thirty-nine (98%) participants completed 8-wk measurements. The exercise group had lower Patient-Rated Tennis Elbow Evaluation scores compared with wait-and-see at 8 wk (standardized mean difference SMD, −0.92; 95% confidence interval CI, −1.58 to −0.26). No group differences were found for success on global rating of change (29% exercise vs 26% wait-and-see (risk difference, 2.3%; 95% CI, −24.5 to 29.1)), or pain-free grip strength (SMD, −0.33; 95% CI, −0.97 to 0.30). No differences were observed for all secondary outcomes except for worst pain, which was moderately lower in the exercise group (SMD, −0.80; 95% CI, −1.45 to −0.14).
Conclusions Unsupervised isometric exercise was effective in improving pain and disability, but not perceived rating of change and pain-free grip strength when compared with wait-and-see at 8 wk. With only one of the three primary outcomes being significantly different after isometric exercises, it is doubtful if this form of exercise is efficacious as a sole treatment.
Aerobic Recovery after Radical Prostatectomy: A Case Study
01-02-2020 – SWAIN, DAVID P.; WYNNE, JAISON L.; WILSON, PATRICK B.
Purpose This case study examined the recovery after radical prostatectomy (RP) of an endurance-trained 65-yr-old man.
Methods A maximal incremental exercise test and a 1-h steady-state test were performed just before and 3 months after robotic RP to determine maximal oxygen consumption (V˙O2max) and other cardiorespiratory variables. The patient recorded his training as he prepared for an endurance event that was to occur 3 months after RP, the Norwegian Foot March, a 30-km road march carrying 11.4 kg.
Results In the month before RP, the patient performed 2 to 3 h of vigorous-intensity aerobic exercise per week, fast walking carrying an 11.4-kg pack, with the longest individual session being a 16-km road march. Just before surgery, V˙O2max was 36.7 m
L·min−1·kg−1, HR during 30 min at 7.2 km·h−1 and 0% grade was 77% of HR reserve (HRR), and during 30 min at 5.3 km·h−1 and 10% grade was 92% HRR. On postsurgery day 44, he did a 19-km road march carrying 11.4 kg, exceeding the training level of the month presurgery. Three months postsurgery, V˙O2max was 42.7 m
L·min−1·kg−1, and HR during the flat and uphill 30-min sessions at the same absolute intensity as presurgery were 70% and 83% HRR, respectively. He completed the Norwegian Foot March 93 d postsurgery in 4:24:37, with an average HR of 72% HRR.
Conclusions This case study demonstrates that an aerobically trained prostate cancer patient can return to high-level aerobic training in as little as 7 wk post-RP, and even exceed presurgery fitness. This finding has implications for prognosis given the beneficial effect of vigorous-intensity exercise on prostate cancer progression.
Moderators of Exercise Effects on Cancer-related Fatigue: A Meta-analysis of Individual Patient Data
01-02-2020 – VAN VULPEN, JONNA K.; SWEEGERS, MAIKE G.; PEETERS, PETRA H. M.; COURNEYA, KERRY S.; NEWTON, ROBERT U.; AARONSON, NEIL K.; JACOBSEN, PAUL B.; GALVÃO, DANIEL A.; CHINAPAW, MAI J.; STEINDORF, KAREN; IRWIN, MELINDA L.; STUIVER, MARTIJN M.; HAYES, SANDI; GRIFFITH, KATHLEEN A.; MESTERS, ILSE; KNOOP, HANS; GOEDENDORP, MARTINE M.; MUTRIE, NANETTE; DALEY, AMANDA J.; MCCONNACHIE, ALEX; BOHUS, MARTIN; THORSEN, LENE; SCHULZ, KARL-HEINZ; SHORT, CAMILLE E.; JAMES, ERICA L.; PLOTNIKOFF, RONALD C.; SCHMIDT, MARTINA E.; ULRICH, CORNELIA M.; VAN BEURDEN, MARC; OLDENBURG, HESTER S.; SONKE, GABE S.; VAN HARTEN, WIM H.; SCHMITZ, KATHRYN H.; WINTERS-STONE, KERRI M.; VELTHUIS, MIRANDA J.; TAAFFE, DENNIS R.; VAN MECHELEN, WILLEM; KERSTEN, MARIE JOSÉ; NOLLET, FRANS; WENZEL, JENNIFER; WISKEMANN, JOACHIM; VERDONCK-DE LEEUW, IRMA M.; BRUG, JOHANNES; MAY, ANNE M.; BUFFART, LAURIEN M.
Purpose Fatigue is a common and potentially disabling symptom in patients with cancer. It can often be effectively reduced by exercise. Yet, effects of exercise interventions might differ across subgroups. We conducted a meta-analysis using individual patient data of randomized controlled trials (RCT) to investigate moderators of exercise intervention effects on cancer-related fatigue.
Methods We used individual patient data from 31 exercise RCT worldwide, representing 4366 patients, of whom 3846 had complete fatigue data. We performed a one-step individual patient data meta-analysis, using linear mixed-effect models to analyze the effects of exercise interventions on fatigue (z score) and to identify demographic, clinical, intervention- and exercise-related moderators. Models were adjusted for baseline fatigue and included a random intercept on study level to account for clustering of patients within studies. We identified potential moderators by testing their interaction with group allocation, using a likelihood ratio test.
Results Exercise interventions had statistically significant beneficial effects on fatigue (β = −0.17; 95% confidence interval CI, −0.22 to −0.12). There was no evidence of moderation by demographic or clinical characteristics. Supervised exercise interventions had significantly larger effects on fatigue than unsupervised exercise interventions (βdifference = −0.18; 95% CI −0.28 to −0.08). Supervised interventions with a duration ≤12 wk showed larger effects on fatigue (β = −0.29; 95% CI, −0.39 to −0.20) than supervised interventions with a longer duration.
Conclusions In this individual patient data meta-analysis, we found statistically significant beneficial effects of exercise interventions on fatigue, irrespective of demographic and clinical characteristics. These findings support a role for exercise, preferably supervised exercise interventions, in clinical practice. Reasons for differential effects in duration require further exploration.
Reporting of Resistance Training Dose, Adherence, and Tolerance in Exercise Oncology
01-02-2020 – FAIRMAN, CIARAN M.; NILSEN, TORMOD S.; NEWTON, ROBERT U.; TAAFFE, DENNIS R.; SPRY, NIGEL; JOSEPH, DAVID; CHAMBERS, SUZANNE K.; ROBINSON, ZAC P.; HART, NICOLAS H.; ZOURDOS, MICHAEL C.; FOCHT, BRIAN C.; PEDDLE-MCINTYRE, CAROLYN J.; GALVÃO, DANIEL A.
Purpose While general guidelines (such as CONSORT or Consensus on Exercise Reporting Template) exist to enhance the reporting of exercise interventions in the field of exercise science, there is inadequate detail facilitating the standardized reporting of resistance training adherence in the oncology setting. The purpose of this study was to apply a novel method to report resistance training dose, adherence, and tolerance in patients with cancer.
Methods A total of 47 prostate cancer patients (70.1 ± 8.9 yr, body mass index, 28.6 ± 4.0) with bone metastatic disease completed an exercise program for 12 wk. We assessed traditional metrics of adherence (attendance and loss to follow-up), in addition to novel proposed metrics (exercise-relative dose intensity, dose modification, and exercise interruption). Total training volume in kilograms (repetitions × sets × training load (weight)) was calculated for each patient.
Results Attendance assessed from traditional metrics was 79.5% ± 17.0% and four patients (9%) were lost to follow-up. The prescribed and actual cumulative total dose of resistance training was 139,886 ± 69,150 kg and 112,835 ± 83,499 kg, respectively, with a mean exercise-relative dose intensity of 77.4% ± 16.6% (range: 19.4% –99.4%). Resistance training was missed (1–2 consecutive sessions) or interrupted (missed ≥3 consecutive sessions) in 41 (87%) and 24 (51%) participants, respectively. Training dose was modified (reduction in sets, repetitions, or weight) in 40 (85%) of patients. Importantly, using attendance as a traditional metric of adherence, these sessions would have all counted as adherence to the protocol.
Conclusions Traditional reporting metrics of resistance training in exercise oncology may overestimate exercise adherence. Our proposed metrics to capture resistance training dose, adherence, and tolerance may have important applications for future studies and clinical practice.
The Effect of Exercise Timing on Glycemic Control: A Randomized Clinical Trial
01-02-2020 – TEO, SHAUN Y. M.; KANALEY, JILL A.; GUELFI, KYM J.; MARSTON, KIERAN J.; FAIRCHILD, TIMOTHY J.
Despite the acknowledgment of exercise as a cornerstone in the management of type 2 diabetes (T2D), the importance of exercise timing has only recently been considered.
Purpose This study sought to determine the effect of diurnal exercise timing on glycemic control in individuals enrolled in a 12-wk supervised multimodal exercise training program. A secondary aim was to determine the effect of diurnal exercise timing on the circadian rhythm of wrist skin temperature.
Methods Forty sedentary, overweight adults (mean ± SD, age = 51 ± 13 yr; body mass index = 30.9 ± 4.2 kg·m−2; women, n = 23) with and without (n = 20) T2D diagnosis were randomly allocated to either a morning (am
EX) or an evening (pm
EX) exercise training group. The supervised 12-wk (3 d·wk−1) program, comprised 30 min of moderate-intensity walking and 4 resistance-based exercises (3 sets, 12–18 repetitions each). Glycemic outcomes (glycated hemoglobin, fasting glucose, postprandial glucose) and wrist skin temperature were assessed at baseline and postintervention.
Results Exercise training improved (main effect of time, all P < 0.01) all glycemic outcomes; however, this was independent of allocation to either the am
EX (Hedge’s g, 0.23–0.90) or the pm
EX (Hedge’s g, 0.16–0.90) group. Accordingly, the adopted exercise training program did not alter the circadian rhythm of skin temperature. When only T2D individuals were compared, am
EX demonstrated greater effects (all Hedge’s g) on glycated hemoglobin (am
EX, 0.57; pm
EX, 0.32), fasting glucose (am
EX, 0.91; pm
EX, 0.53), and postprandial glucose (am
EX, 1.12; pm
EX, 0.71) but was not statistically different.
Conclusions Twelve weeks of multimodal exercise training improved glycemic control and postprandial glycemic responses in overweight non-T2D and T2D individuals. However, no distinct glycemic benefits or alterations in circadian rhythm were associated with morning versus evening exercise, when performed three times per week in this cohort.
The Effects of Transcranial Direct Current Stimulation on Chronic Ankle Instability
01-02-2020 – BRUCE, AMELIA S.; HOWARD, JENNIFER S.; VAN WERKHOVEN, HERMAN; MCBRIDE, JEFFREY M.; NEEDLE, ALAN R.
Purpose Given maladaptive neuroplasticity after musculoskeletal injury, interventions capable of restoring corticospinal excitability should be considered. We therefore aimed to determine if a 4-wk intervention of anodal transcranial direct current stimulation (a
TDCS) with eccentric exercise would improve neural excitability, functional performance, and patient-reported function in individuals with chronic ankle instability (CAI).
Methods Twenty-six individuals with CAI were recruited to undergo 4 wk of eccentric evertor strengthening. Subjects were randomized into a
TDCS (n = 13) and sham (n = 13) groups, where the a
TDCS group received 18 min of a
TDCS (1.5 m
A) over the primary motor cortex. Participants were assessed for cortical excitability, dynamic balance, muscle activation, functional performance, strength, and patient-reported function at baseline, week 2, week 4, and week 6.
Results Twenty-two subjects completed the training and test sessions. Cortical excitability (resting motor threshold) to peroneus longus in a
TDCS increased from baseline (36.92 ± 11.53) to week 6 (32.91 ± 12.33, P = 0.024), whereas sham increased excitability from baseline (36.67 ± 12.74) to week 2 (27.86 ± 14.69, P = 0.007), but decreased at week 4 (35.63 ± 13.10, P = 0.022) and week 6 (35.99 ± 13.52, P = 0.006). Dynamic balance and muscle activation also improved in the a
TDCS group from baseline to week 6 (P = 0.034). Functional performance on a side-hop test increased in all participants from baseline to week 2 (P = 0.003). The a
TDCS group had decreased perceived disablement from week 2 (18.09 ± 6.41) to week 4 (15.55 ± 4.82, P = 0.046), whereas the sham group reported increased disablement from baseline (17.91 ± 4.59) to week 2 (21.00 ± 8.52, P = 0.047).
Conclusions Our results provide preliminary evidence that 4 wk of eccentric training with a
TDCS improves cortical excitability, functional performance, and patient-reported function in individuals with CAI. These data are the first to show the efficacy of noninvasive brain stimulation therapies in patients with musculoskeletal injury, and demonstrate the link between improved neural excitability and functional outcomes.
Are Anterior Cruciate Ligament–reconstructed Athletes More Vulnerable to Fatigue than Uninjured Athletes?
01-02-2020 – SMEETS, ANNEMIE; VANRENTERGHEM, JOS; STAES, FILIP; VANDENNEUCKER, HILDE; CLAES, STEVEN; VERSCHUEREN, SABINE
Introduction Fatigue has a negative impact on lower extremity neuromuscular and biomechanical control. Because anterior cruciate ligament reconstruction (ACLR) athletes show already neuromuscular/biomechanical deficits in an unfatigued state, the negative impact of fatigue may magnify these deficits or help expose other deficits. So far, this has only scarcely been assessed warranting further research.
Methods Twenty-one athletes who had an ACLR and 21 uninjured controls performed five unilateral landing tasks before and after a match simulation protocol, whereas muscle activation (vastus medialis, vastus lateralis, hamstrings medialis, hamstrings lateralis, gastrocnemius medialis, gastrocnemius lateralis, gluteus medius) and landing kinematics and kinetics of the hip, knee, and ankle joint were recorded. A two-way ANOVA with a mixed-model design (main effects for group and fatigue) was used to compare landing kinematics, kinetics, and muscle activation between groups, and prefatigue and postfatigue. To avoid unjustified reduction of the data to discrete values, we used one-dimensional Statistical Parametric Mapping.
Results Only two interaction effects were found: an increased postfatigue knee abduction moment and an increased postfatigue thorax flexion angle was found in the ACL injured legs but not in the uninjured legs of the ACL group or in the control group, during the lateral hop and the vertical hop with 90° medial rotation, respectively.
Conclusions This study showed that overall ACLR athletes and uninjured athletes have similar biomechanical and neuromuscular responses to fatigue. For two biomechanical parameters, however, we did find an interaction effect, suggesting that landing deficits in ACLR athletes may become clearer in certain tasks when fatigued.
Plasmalemma Function Is Rapidly Restored in Mdx Muscle after Eccentric Contractions
01-02-2020 – BAUMANN, CORY W.; WARREN, GORDON L.; LOWE, DAWN A.
Purpose Muscle that lacks dystrophin, as in the mdx mouse, has a heightened sensitivity to eccentric (ECC) contraction-induced strength loss but an enhanced rate of recovery. However, the timeline and mechanisms underlying why mdx muscle recovers quicker have yet to be determined. We used an EMG approach to analyze plasmalemma electrophysiological function during and after ECC contraction-induced injury to test the hypothesis that loss of plasmalemmal excitability is a transient event in mdx muscle.
Methods Mice were implanted with stimulating electrodes on the common peroneal nerve and EMG electrodes on the tibialis anterior muscle. Anterior crural muscles of anesthetized mice performed one or two bouts of 50 injurious ECC contractions, and recovery of maximal isometric torque and M-wave root mean square (RMS) were assessed after each bout.
Results Maximal isometric torque and M-wave RMS were equally reduced 62% (P < 0.001) in mdx mice immediately after the initial ECC injury. For these mdx mice, M-wave RMS was still reduced at 2 d postinjury (P = 0.034) but was not different from preinjury values by 6 d (P = 0.106), whereas torque took up to 9 d to recover (P = 0.333). M-wave RMS did not change (P = 0.390) in wild-type mice in response to ECC injury, whereas torque decreased 35% (P < 0.001) and recovered by day 2 (P = 0.311). Results from the second bout of ECC contractions were similar to those observed during and after the initial injury.
Conclusion Functional dystrophin is necessary for excitation to occur at the plasmalemma during ECC contractions but is not essential for the complete recovery of plasmalemma electrophysiological function or maximal isometric strength.
Fluid Loss during Exercise-Heat Stress Reduces Cardiac Vagal Autonomic Modulation
01-02-2020 – MACARTNEY, MICHAEL J.; MEADE, ROBERT D.; NOTLEY, SEAN R.; HERRY, CHRISTOPHE L.; SEELY, ANDREW J. E.; KENNY, GLEN P.
Purpose Sweat-induced fluid loss during prolonged exercise-heat stress can compromise cardiovascular and thermoregulatory function, although its effects on cardiac autonomic modulation remain unclear. We therefore examined heart rate variability (HRV) and recovery (HRRec), as surrogates of cardiac autonomic modulation, during and after prolonged exercise in the heat with and without fluid replacement.
Methods Eleven young and healthy men performed 90 min of semi-recumbent cycling in dry heat (40°C; 20% relative humidity) at a fixed rate of metabolic heat production (600 W; ~46% V˙O2peak) followed by 40-min resting recovery without fluid replacement (No-FR; ~3.4% reduction in body mass). On a separate day, participants completed the same protocol with fluid replacement (FR; 500–700 m
L timed boluses) to offset sweat losses. Esophageal temperature and ECG were recorded throughout, with measurements analyzed over 10-min averaged epochs during baseline, each 30-min interval during exercise and 20-min interval during recovery.
Results Esophageal temperature and heart rate were elevated in No-FR relative to FR throughout exercise (all P ≤ 0.02). The HRV indices reflecting vagal influence of heart rate including the cardiac vagal index (CVI = log1016 × SD1 × SD2) and root-mean-square of successive differences were attenuated throughout exercise relative to baseline in both conditions (all P < 0.05), with the magnitude of the reduction greater in the No-FR condition (all P < 0.05). Further, sample entropy was reduced throughout all time points measured during exercise in the No-FR relative to FR condition (all P ≤ 0.03).
Conclusions Our unique observations indicate that while prolonged exercise heat stress attenuates the vagal influence and complexity of cardiac rhythms, that reduction is further exacerbated by fluid loss, highlighting the importance of fluid replacement in such conditions.
Fibroblast Growth Factor 21 Mediates the Associations between Exercise, Aging, and Glucose Regulation
01-02-2020 – LEE, SHUEN YEE; BURNS, STEPHEN F.; NG, KENNETH K. C.; STENSEL, DAVID J.; ZHONG, LIANG; TAN, FRANKIE H. Y.; CHIA, KAR LING; FAM, KAI DENG; YAP, MARGARET M. C.; YEO, KWEE POO; YAP, ERIC P. H.; LIM, CHIN LEONG
Introduction Aging increases the prevalence of glucose intolerance, but exercise improves glucose homeostasis. The fibroblast growth factor 21 (FGF21)–adiponectin axis helps regulate glucose metabolism. However, the role of FGF21 in mediating glucose metabolism with aging and exercise remains unknown.
Purpose This study examined whether FGF21 responses to a glucose challenge are associated with habitual exercise, aging and glucose regulation.
Methods Eighty age- and sex-matched healthy individuals were assigned to young sedentary and active (≤36 yr, n = 20 each group) and older sedentary and active (≥45 yr, n = 20 each group) groups. Fasted and postprandial blood glucose concentration and plasma concentration of insulin, FGF21, and adiponectin were determined during an oral glucose tolerance test (OGTT).
Results During the OGTT, glucose concentrations were 9% higher (P = 0.008) and FGF21 concentrations were 58% higher (P = 0.014) in the older than the younger group, independent of activity status. Active participants had 40% lower insulin concentration and 53% lower FGF21 concentration than sedentary participants, independent of age (all P < 0.001). Adiponectin concentration during the OGTT did not differ by age (P = 0.448) or activity status (P = 0.611). Within the younger group, postprandial glucose, insulin and FGF21 concentrations during the OGTT were lower in active than in sedentary participants. In the older group, only postprandial insulin and FGF21 concentrations were lower in active participants.
Conclusions FGF21, but not adiponectin, response during the OGTT is higher in older than younger adults and lower in active than sedentary individuals. Exercise-associated reduction in OGTT glucose concentrations was observed in younger but not older adults.
Physical Activity and Academic Performance: Genetic and Environmental Associations
01-02-2020 – AALTONEN, SARI; LATVALA, ANTTI; JELENKOVIC, ALINE; ROSE, RICHARD J.; KUJALA, URHO M.; KAPRIO, JAAKKO; SILVENTOINEN, KARRI
Introduction Physical activity and academic performance are believed to be associated. Though both traits are partially heritable, it remains unclear whether these traits also share a genetic and/or environmental background in common. We aimed to examine to what extent leisure time physical activity and academic performance share genetic and environmental effects from early adolescence to young adulthood.
Methods Participants were Finnish twins (2543–2693 individuals/study wave) who reported their leisure-time physical activity at ages 12, 14, 17, and 24 yr. Academic performance was assessed with teacher-reported grade point averages at ages 12 and 14 yr and by self-reported educational levels at ages 17 and 24 yr. Bivariate quantitative genetic modeling at each age and between different ages was performed to decompose the trait correlation between academic performance and physical activity into genetic and environmental components.
Results The trait correlations between leisure-time physical activity and academic performance were positive, but modest at most (rtrait = 0.08–0.22 in males, and 0.07–0.18 in females). The genetic correlations between leisure-time physical activity and academic performance were higher than the trait correlations (r
A = 0.17–0.43 in males, and 0.15–0.25 in females). Common genetic influences explained 43% to 100% of the trait correlations. Environmental influences shared by cotwins between leisure-time physical activity and academic performance were also correlated (r
C = 0.27–0.54 in males, and 0.21–0.69 in females) explaining 41% to 100% of the trait correlations. Unique environmental influences were correlated only in females (r
E = 0.10–0.15).
Conclusions Both common genetic background and shared family environment (i.e., familial background) partially account for the associations observed between leisure-time physical activity and academic performance. However, the estimates vary in magnitude by age.
activPAL and ActiGraph Assessed Sedentary Behavior and Cardiometabolic Health Markers
01-02-2020 – EDWARDSON, CHARLOTTE L.; HENSON, JOSEPH; BIDDLE, STUART J. H.; DAVIES, MELANIE J.; KHUNTI, KAMLESH; MAYLOR, BENJAMIN; YATES, THOMAS
Purpose To establish whether associations between sedentary behavior and cardiometabolic health differ when assessed by thigh-worn and waist-worn accelerometry.
Methods Participants were recruited from several areas in the United Kingdom. Sedentary behavior was assessed using the activ
PAL worn on the thigh and Acti
Graph worn on the waist. Average total (TST), prolonged (bouts ≥30 min; PST) and breaks (BST) in sedentary time were calculated. Cardiometabolic health markers included: adiposity (body fat) and surrogate markers of adiposity ((waist circumference, body mass index BMI), lipids (total, low density lipoprotein, and high-density lipoprotein HDL cholesterol, triglycerides), blood pressure, and glucose (fasting, 2 h and glycated hemoglobin A1c). A clustered cardiometabolic risk score was calculated. Linear regression analysis examined the associations with cardiometabolic health.
Results There were 1457 participants (mean age ± standard deviation, 59.38 ± 11.85 yr; 51.7% male; mean BMI, 30.19 ± 5.59 kg·m−2) included in the analyses. Activ
PAL and Acti
Graph sedentary variables were moderately correlated (0.416–0.511, P < 0.01); however, all variables were significantly different from each other (P < 0.05). Consistency was observed across devices in the direction and magnitude of associations of TST and PST with adiposity, surrogate markers of adiposity, HDL, triglycerides, and cardiometabolic risk score and for BST with adiposity, surrogate markers of adiposity, and cardiometabolic risk. Differences across devices were observed in associations of TST and PST with diastolic blood pressure, for TST with 2-h glucose and for BST with HDL. No other associations were observed for any other health marker for either device.
Conclusions Results suggest that associations with cardiometabolic health are largely comparable across the two common assessments of sedentary behavior but some small differences may exist for certain health markers.
Individualized Relative-Intensity Physical Activity Accelerometer Cut Points
01-02-2020 – SIDDIQUE, JUNED; AABY, DAVID; MONTAG, SAMANTHA E.; SIDNEY, STEPHEN; STERNFELD, BARBARA; WELCH, WHITNEY A.; CARNETHON, MERCEDES R.; LIU, KIANG; CRAFT, LYNETTE L.; PETTEE GABRIEL, KELLEY; BARONE GIBBS, BETHANY; REIS, JARED P.; FREEDSON, PATTY
Purpose Physical activity (PA) intensity is expressed as either absolute or relative intensity. Absolute intensity refers to the energy required to perform an activity. Relative intensity refers to a level of effort that takes into account how hard an individual is working relative to their maximum capacity. We sought to develop methods for obtaining individualized relative-intensity accelerometer cut points using data from a maximal graded exercise treadmill test (GXT) so that each individual has their own cut point.
Methods A total of 2363 men and women 38 to 50 yr old from the CARDIA fitness study wore Acti
Graph 7164 accelerometers during a maximal GXT and for seven consecutive days in 2005–2006. Using mixed-effects regression models, we regressed accelerometer counts on heart rate as a percentage of maximum (%HRmax) and on RPE. Based on these two models, we obtained a moderate-intensity (%HRmax = 64% or RPE = 12) count cut point that is specific to each participant. We applied these subject-specific cut points to the available CARDIA accelerometer data.
Results Using RPE, the mean moderate-intensity accelerometer cut point was 4004 (SD = 1120) counts per minute. On average, cut points were higher for men (4189 counts per minute) versus women (3865 counts per minute) and were higher for Whites (4088 counts per minute) versus African Americans (3896 counts per minute). Cut points were correlated with body mass index (rho = −0.11) and GXT duration (rho = 0.33). Mean daily minutes of absolute- and relative-intensity moderate to vigorous PA were 34.1 (SD = 31.1) min·d−1 and 9.1 (SD = 18.2) min·d−1, respectively. RPE cut points were higher than those based on %HRmax. This is likely due to some participants ending the GXT before achieving their HRmax.
Conclusions Accelerometer-based relative-intensity PA may be a useful measure of intensity relative to maximal capacity.
A Randomized Community-based Exercise Training Trial in African American Men: Aerobic Plus Resistance Training and Insulin Sensitivity in African American Men
01-02-2020 – NEWTON, ROBERT L. Jr; JOHNSON, WILLIAM D.; LARRIVEE, SANDRA; HENDRICK, CHELSEA; HARRIS, MELISSA; JOHANNSEN, NEIL M.; SWIFT, DAMON L.; HSIA, DANIEL S.; CHURCH, TIMOTHY S.
Purpose To examine the impact of a community-based exercise training intervention on cardiometabolic outcomes in African American men who have a family history of type 2 diabetes.
Methods The Aerobic Plus Resistance Training and Insulin Sensitivity in African American Men (ARTIIS) study randomized participants into either an exercise training intervention or an information only control group for 5 months. The exercise training intervention consisted of 150 min of moderate intensity aerobic activity and 2 d of resistance training per week, consistent with the current federal physical activity guidelines. Participants in the control group received monthly newsletters featuring topics focused heavily on type 2 diabetes education and prevention. Outcome data were analyzed using repeated-measures ANCOVA models and incorporating both intention-to-treat and per-protocol principles.
Results Adherence to the aerobic and resistance training prescriptions were between 77% and 79%. Despite significant within group improvements in glucose and insulin levels (fasting, 2 h, 2 h minus baseline) and Homeostatic Model 2-Insulin Resistance, there were not significant between group differences. There was a marginally significant between group difference for Homeostatic Model 2-Beta (P < 0.06), and significant between group differences in peak cardiorespiratory fitness (P < 0.001) and waist circumference (P = 0.03).
Conclusions These findings suggest that exercise training in accordance with the current national recommendations is effective in improving some health parameters in middle-age African American men who have a family history of type 2 diabetes, but did not have a significant impact on glycemic status.
The Effects of Water-based Exercise Training in People with Type 2 Diabetes
01-02-2020 – SCHEER, ANNA S.; NAYLOR, LOUISE H.; GAN, SENG K.; CHARLESWORTH, JONATHON; BENJANUVATRA, NAT; GREEN, DANIEL J.; MAIORANA, ANDREW J.
Purpose To investigate the effects of 8 wk of upright water-based exercise training in people with type 2 diabetes.
Methods Thirteen participants with type 2 diabetes (54% male; 60.9 ± 9.6 yr, mean ± standard deviation) completed 8 wk of upright water-based exercise training at a moderate intensity (60%–80% of exercise test-derived maximum HR), for 1 h, three times a week (TG). Fourteen participants (64% male; 63.9 ± 9.8 yr) acted as a control group (CG) who maintained their usual activities. Preintervention and postintervention, participants performed cardiopulmonary exercise testing to determine V˙O2peak and one-repetition maximum testing to assess muscular strength. Blood profiles were assessed with standard assays. Body mass index and waist/hip ratio were employed as measures of anthropometry. Endothelium-dependent (brachial artery flow-mediated dilation) and independent (glyceryl trinitrate-mediated) function were assessed using vascular ultrasound.
Results Water-based training increased V˙O2peak (18.5 ± 4.3 m
L·kg−1·min−1 to 21.5 ± 5.4 m
L·kg−1·min−1) (P = 0.002), overall muscle strength (123 ± 44 kg to 139 ± 43 kg) and leg strength (92 ± 28 kg to 104 ± 29 kg), compared with the CG (P = 0.001). The effect on pectoral strength (31 ± 17 kg to 35 ± 16 kg) was not significantly different to the CG (24 ± 12 kg to 26 ± 14 kg) (P = 0.08). No change was observed in anthropometry, blood profiles, or glyceryl trinitrate-mediated vascular function. Flow-mediated dilation was increased after training (6.1% ± 2.4% to 6.5% ± 3.0%), compared with controls who demonstrated a slight decrease (6.2% ± 1.6% to 5.4% ± 1.6%) (P = 0.002).
Conclusions Water-based circuit training was well tolerated and appears to be an effective exercise modality for improving aerobic fitness, strength, and vascular function in people with type 2 diabetes.
A Mobile Application for Exercise Intervention in People Living with HIV
01-02-2020 – BONATO, MATTEO; TURRINI, FILIPPO; DE ZAN, VALENTINA; MELONI, ANDREA; PLEBANI, MARTA; BRAMBILLA, ELENA; GIORDANI, ALESSANDRA; VITOBELLO, CHIARA; CACCIA, ROBERTA; PIACENTINI, MARIA FRANCESCA; LA TORRE, ANTONIO; LAZZARIN, ADRIANO; MERATI, GIAMPIERO; GALLI, LAURA; CINQUE, PAOLA
Purpose This study aimed to assess 16-wk improvements of physical fitness, metabolic, and psychological parameters in people living with HIV (PLWH) exercising with the support of a smartphone application, as compared with a control group exercising without application.
Methods This was a randomized, open-label, pilot study enrolling PLWH in a 16-wk protocol consisting of moderate physical activity three times per week, which included an initial coach-supervised period of 4 wk, followed by 12 wk where participants trained independently. Participants were allocated to either an experimental group that trained using a smartphone application (APP) or a control group that practiced following a hard copy training program (No-APP). At baseline (BL) and after 16 wk (W16), patients were assessed for cardiorespiratory fitness, body composition, blood lipid profile, and POMS.
Results Forty-eight PLWH were screened and 38 were eligible: 20 were allocated to the APP group and 18 to the No-APP group. Two APP and two No-APP participants were lost to follow-up. Intention-to-treat analysis showed a W16 improvement from BL of ≥15% V˙ O2peak in 13 (72%) of 18 in APP, but only in 3 (19%) of 16 in No-APP participants (P = 0.025). Significant W16 improvements were observed in APP, but not in No-APP participants, in V˙O2peak; fat mass and fat-free mass percent; total cholesterol, LDL cholesterol, and triglycerides; vigor; and total mood by POMS. Accordingly, significant percent change differences between the APP and the No-APP groups were observed in V˙O2peak; fat and fat-free mass percent; total cholesterol, LDL cholesterol, and triglycerides; and depression, vigor, anger, and total mood by POMS.
Conclusions Exercising using a smartphone application improved cardiorespiratory fitness, body composition, cholesterol profiles, and psychological outcomes in PLWH.
Skeletal Effects of Nine Months of Physical Activity in Obese and Healthy Weight Children
01-02-2020 – KONDIBOYINA, VINEEL; RAINE, LAUREN B.; KRAMER, ARTHUR F.; KHAN, NAIMAN A.; HILLMAN, CHARLES H.; SHEFELBINE, SANDRA J.
Purpose Obesity during adolescence has multisystem health consequences. The objective of this work was to determine whether preadolescent overweight/obese children’s bones respond to a 9-month physical activity intervention by increasing bone density similar to healthy weight children.
Methods Participants included overweight/obese (BMI > 85%) and healthy weight (15% < BMI < 85%) preadolescents (8–9 yr old). Participants in the physical activity group participated in a 9-month physical activity curriculum every day after school. The wait list control group received no intervention. Both groups had overweight/obese children and healthy weight controls. Whole-body bone mineral content, area, and bone mineral apparent density (BMAD) were assessed using dual x-ray absorptiometry) at the beginning and end of the 9-month trial in the physical activity and control group.
Results Overweight/obese preadolescent children had higher BMAD than healthy weight children (P < 0.001 for spine, leg, and whole body). However, the density/weight (BMAD/lean mass) was lower in overweight/obese children than that in healthy weight children, indicating that the density of bones in overweight/obese children may not compensate sufficiently for the excessive load due to weight. The change in BMAD over 9 months was greater in healthy weight children than overweight/obese children in the whole body and leg, but not the lumbar spine. Physical activity caused a site-specific increase in bone density, affecting the legs more than the lumbar spine, but there was no significant difference in the effect of exercise between the healthy weight and the overweight/obese group.
Conclusions The smaller change in BMAD over the 9 months and lower BMAD per unit lean mass in overweight/obese compared with healthy weight children may indicate a slower rate of bone mass accrual, which may have implications for bone health during skeletal growth in obese/overweight children.
Feasibility and Effects on Muscle Function of an Exercise Program for Older Adults
01-02-2020 – MINETT, MAGGIE M.; BINKLEY, TERESA L.; HOLM, RICHARD P.; RUNGE, MARTIN; SPECKER, BONNY L.
Introduction Study objective was to determine feasibility and compliance with a 3-month exercise intervention in older adults, and if peripheral quantitative computed tomography muscle measures and jumping mechanography could detect changes in muscle mass and function.
Methods A parallel group, nonblinded, pilot trial with individuals 70 yr or older randomized to control group of walking-only (WALK) or an intervention group of walking combined with exercises to improve balance and strength (W + EX). Both groups attended similar weekly nutrition education sessions. Body composition, muscle density, intramuscular adipose tissue area, and muscle function were assessed before and after the intervention using dual-energy x-ray, peripheral quantitative computed tomography, functional tests, and mechanography.
Results Eighty-five (90%) of 94 individuals enrolled completed (41WALK, 44W + EX). Eighty-six percent of participants attended seven or more nutrition sessions, and log sheets, used to assess exercise compliance, were returned by 66% of participants, and of those, 88% logged activity on 50%+ days. Sixty-seven percent of participants stated that they increased activity levels, and 82% stated that they felt better overall. Both groups increased lean and lost fat mass, resulting in decreases in fat percentage (all, P < 0.05). Intramuscular adipose tissue area decreased and muscle density increased among WALK (P < 0.05 and P = 0.056, respectively) but were not different between groups. Improvement in force efficiency and chair-rise power were greater among W + EX group than WALK (5.9% ± 1.8% vs −1.2% ± 2.0% P = 0.01 and 0.25 ± 0.19 W·kg−1 and −0.37 ± 0.23 W·kg−1 P = 0.04, respectively). Differences in mechanography results became greater in a per-protocol analysis.
Conclusions A larger trial is feasible, and the program was well accepted. Both groups showed improvements, the program that included strength and balance lead to greater jump force efficiency and power than walking only. Whether these differences lead to differences in fall rates need to be determined in a larger trial.
Physical Performance Measures Correlate with Head Impact Exposure in Youth Football
01-02-2020 – KELLEY, MIREILLE E.; JONES, DEREK A.; ESPELAND, MARK A.; ROSENBERG, MEAGAN L.; MILES, CHRISTOPHER M.; WHITLOW, CHRISTOPHER T.; MALDJIAN, JOSEPH A.; STITZEL, JOEL D.; URBAN, JILLIAN E.
Purpose Head impact exposure (HIE) (i.e., magnitude and frequency of impacts) can vary considerably among individuals within a single football team. To better understand individual-specific factors that may explain variation in head impact biomechanics, this study aimed to evaluate the relationship between physical performance measures and HIE metrics in youth football players.
Methods Head impact data were collected from youth football players using the Head Impact Telemetry System. Head impact exposure was quantified in terms of impact frequency, linear and rotational head acceleration, and risk-weighted cumulative exposure metrics (RWELinear, RWERotational, and RWECP). Study participants completed four physical performance tests: vertical jump, shuttle run, three-cone, and 40-yard sprint. The relationships between performance measures, and HIE metrics were evaluated using linear regression analyses.
Results A total of 51 youth football athletes (ages, 9–13 yr) completed performance testing and received combined 13,770 head impacts measured with the Head Impact Telemetry System for a full season. All performance measures were significantly correlated with total number of impacts in a season, RWELinear-Season, and all RWE-Game metrics. The strongest relationships were between 40-yard sprint speed and all RWE-Game metrics (all P ≤ 0.0001 and partial R2 > 0.3). The only significant relationships among HIE metrics in practice were between shuttle run speed and total practice impacts and RWELinear-Practices, 40 yard sprint speed and total number of practice impacts, and three-cone speed and 95th percentile number of impacts/practice.
Conclusions Generally, higher vertical jump height and faster times in speed and agility drills were associated with higher HIE, especially in games. Physical performance explained less variation in HIE in practices, where drills and other factors, such as coaching style, may have a larger influence on HIE.
Breaking Up Sedentary Behavior Optimally to Enhance Mood
01-02-2020 – GIURGIU, MARCO; KOCH, ELENA D.; PLOTNIKOFF, RONALD C.; EBNER-PRIEMER, ULRICH W.; REICHERT, MARKUS
Introduction Experimental evidence shows that breaking-up sedentary behavior is positively associated with positive mental health outcomes. However, whether sedentary breaks influence mood in everyday life is largely unknown. Moreover, it is unclear which break patterns are most beneficial to enhance mood.
Methods To investigate the degree to which sedentary break patterns influence mood dimensions in everyday life, we conducted an Ecological Momentary Assessment study in 92 university employees over 5 d. We continuously measured physical behavior (physical activity and sedentary behavior) objectively via accelerometers and assessed mood 10 times a day on smartphone diaries. We defined distinct break patterns, such as variations in frequency (number of breaks), duration (length of breaks), intensity (metabolic equivalent), and context (home or work) and used multilevel modeling to analyze the within-subject effects of sedentary break patterns on mood.
Results Break intensity was positively associated with subsequent valence (P < 0.01), energetic arousal (P < 0.01), and calmness (P < 0.05). Break frequency was positively associated with subsequent valence and energetic arousal (all P’s < 0.01), but break duration was not associated with mood. Exploratory analyses indicated that breaking-up sedentary behavior was more beneficial at home than at work.
Conclusions These ecologically valid findings suggest breaking-up sedentary behavior as a promising strategy to enhance mood in everyday life. In particular, breaking-up sedentary behavior frequently and intensively, for example, by walking instead of standing, may be most beneficial. We call for future studies to substantiate these accounts and to identify both practical and optimal break patterns among different samples. This evidence informs official public health recommendations aiming to “minimize sedentary time in everyday life.”
A Critical Evaluation of Current Methods for Exercise Prescription in Women and Men
01-02-2020 – IANNETTA, DANILO; INGLIS, ERIN CALAINE; MATTU, ANMOL T.; FONTANA, FEDERICO Y.; POGLIAGHI, SILVIA; KEIR, DANIEL A.; MURIAS, JUAN M.
Common methods to prescribe exercise intensity are based on fixed percentages of maximum rate of oxygen uptake (V˙O2max), peak work rate (WRpeak), maximal HR (HRmax). However, it is unknown how these methods compare to the current models to partition the exercise intensity spectrum.
Purpose Thus, the aim of this study was to compare contemporary gold-standard approaches for exercise prescription based on fixed percentages of maximum values to the well-established, but underutilized, “domain” schema of exercise intensity.
Methods One hundred individuals participated in the study (women, 46; men, 54). A cardiopulmonary ramp-incremental test was performed to assess V˙O2max, WRpeak, HRmax, and the lactate threshold (LT), and submaximal constant-work rate trials of 30-min duration to determine the maximal lactate steady-state (MLSS). The LT and MLSS were used to partition the intensity spectrum for each individual in three domains of intensity: moderate, heavy, and severe.
Results V˙O2max in women and men was 3.06 ± 0.41 L·min−1 and 4.10 ± 0.56 L·min−1, respectively. Lactate threshold and MLSS occurred at a greater %V˙O2max and %HRmax in women compared with men (P < 0.05). The large ranges in both sexes at which LT and MLSS occurred on the basis of %V˙O2max (LT, 45%–74%; MLSS, 69%–96%), %WRpeak (LT, 23%–57%; MLSS, 44%–71%), and %HRmax (LT, 60%–90%; MLSS, 75%–97%) elicited large variability in the number of individuals distributed in each domain at the fixed-percentages examined.
Conclusions Contemporary gold-standard methods for exercise prescription based on fixed-percentages of maximum values conform poorly to exercise intensity domains and thus do not adequately control the metabolic stimulus.
Contralateral Effects by Unilateral Eccentric versus Concentric Resistance Training
01-02-2020 – TSENG, WEI-CHIN; NOSAKA, KAZUNORI; TSENG, KUO-WEI; CHOU, TAI-YING; CHEN, TREVOR C.
Purpose Unilateral resistance training increases muscle strength of the contralateral homologous muscle by the cross-education effect. Muscle damage induced by second eccentric exercise bout is attenuated, even when it is performed by the contralateral limb. The present study compared the effects of unilateral eccentric training (ET) and concentric training (CT) of the elbow flexors (EF) on maximal voluntary isometric contraction (MVC) strength and muscle damage of the contralateral untrained EF.
Methods Young men were placed into ET, CT, ipsilateral repeated bout (IL-RB), and contralateral repeated bout (CL-RB) groups (n = 12 per group). The ET and CT groups performed unilateral EF training consisting of five sets of six eccentric and concentric contractions, respectively, once a week for 5 wk by increasing the intensity from 10% to 100% of MVC, followed by 30 maximal eccentric contractions (30Max
EC) of the opposite EF 1 wk later. The IL-RB group performed two bouts of 30Max
EC separated by 2 wk using the nondominant arm, and CL-RB group performed two bouts of 30Max
EC with a different arm for each bout in 1-wk apart.
Results The MVC increased (P < 0.05) greater for the trained (19% ± 8%) and untrained (11% ± 5%) arms in ET when compared with those in CT (10% ± 6%, 5% ± 2%). The magnitude of changes in muscle damage markers was reduced by 71% ± 19% after the second than the first bout for IL-RB group, and by 48% ± 21% for CL-RB group. Eccentric training and CT attenuated the magnitude by 58% ± 25% and 13% ± 13%, respectively, and the protective effect of ET was greater (P < 0.05) than CL-RB, but smaller (P < 0.05) than IL-RB.
Conclusions These results showed that cross-education effect was stronger for ET than CT, and progressive ET produced greater contralateral muscle damage protective effect than a single eccentric exercise bout.
Does Eccentric-only and Concentric-only Activation Increase Power Output?
01-02-2020 – KRZYSZTOFIK, MICHAL; WILK, MICHAL; GOLAS, ARTUR; LOCKIE, ROBERT GEORGE; MASZCZYK, ADAM; ZAJAC, ADAM
Purpose The aim of study was to evaluate changes in power output and bar velocity in the bench press throw (BPT) following the bench press (BP) exercise as a conditioning activity (CA) with concentric only (CONONLY) and eccentric only (ECCONLY) contractions.
Methods Thirty-two (n = 32) healthy strength-trained men participated in this study (age, 28.4 ± 4.5 yr; height, 177 ± 7.6 cm; body mass, 93.5 ± 9.3 kg; BP one-repetition maximum (1RM), 143.6 ± 17.5 kg). The experiment was performed following a randomized crossover design, where each participant performed 2 sets of 2 repetitions using the BP exercise as the CA at 90% 1RM ECCONLY, 90% 1RM CONONLY, 110% 1RM ECCONLY, or 130% 1RM ECCONLY contraction. The BPT was performed to assess changes in peak power (PP), mean power (MP), and peak velocity (PV), mean velocity (MV) before and after CA. The differences between analyzed variables before and after the CA were verified using ANOVA with repeated measures. Statistical significance was set at P < 0.05.
Results There were statistically significant differences between baseline and postactivation value of PP and PV in the BPT (P < 0.05) after the CA with ECCONLY contraction at 110% 1RM and at 130% 1RM as well between baseline and postactivation value of MV in the BPT (P < 0.05) after CA with contraction at 110% 1RM. There were no significant differences between baseline and postactivation values of PP, MP, PV, and MV in the BPT after the CA with CONONLY contraction at 90% 1RM and CA with ECCONLY contraction at 90% 1RM.
Conclusions Partial movement with ECCONLY contraction is effective in short-term power output development, but only when the load used in the CA exceeds 100% 1RM.
Individual Response to Standardized Exercise: Total and Abdominal Adipose Tissue
01-02-2020 – BRENNAN, ANDREA M.; DAY, ANDREW G.; COWAN, THERESA E.; CLARKE, GREGORY J.; LAMARCHE, BENOIT; ROSS, ROBERT
Purpose (1) Determine the effect of exercise amount and intensity on the proportion of individuals for whom the adipose tissue (AT) response is above the minimal clinically important difference (MCID); and (2) Examine whether clinically meaningful anthropometric changes reflect individual AT responses above the MCID.
Methods Men (n = 41) and women (n = 62) (52.7 ± 7.6 yr) were randomized to control (n = 20); low amount low intensity (n = 24); high amount low intensity (n = 30); and high amount high intensity (n = 29) treadmill exercise for 24 wk. The AT changes were measured by MRI. 90% confidence intervals for each individual’s observed response were calculated as the observed score ±1.64 × TE (technical error of measurement).
Results For visceral AT, HAHI and HALI had a greater proportion of individuals whose AT change and 90% confidence interval were beyond the MCID compared to controls (P < 0.006). For all other AT depots, all exercise groups had significantly more individuals whose changes were beyond the MCID compared with controls. Of those who achieved a waist circumference or body weight reduction ≥ the MCID, 76% to 93% achieved abdominal, abdominal subcutaneous, and visceral AT changes ≥ the MCID.
Conclusions Increasing exercise amount and/or intensity may increase the proportion of individuals who achieve clinically meaningful visceral AT reductions. Waist circumference or body weight changes beyond a clinically meaningful threshold are predictive of clinically meaningful abdominal adiposity changes.
Body Composition as a Mediator between Cardiorespiratory Fitness and Bone Mass during Growth
01-02-2020 – RODRÍGUEZ-GÓMEZ, IRENE; MARTÍN-GARCÍA, MARÍA; GARCÍA-CUARTERO, BEATRIZ; GONZÁLEZ-VERGAZ, AMPARO; CARCAVILLA, ATILANO; ARAGONÉS, ÁNGEL; ALEGRE, LUIS M.; ARA, IGNACIO
Introduction and Purpose To examine the effect of cardiorespiratory fitness (CRF) and muscle power output (MPO) on bone mass of prepubertal and pubertal children using lean mass (LM) and percentage of fat mass (%FM) as mediator variables. The hypothesis was that both LM and %FM would be independent mediators of the relationships during the sexual maturation period.
Methods We analyzed 200 children (88 boys and 112 girls 11.5 ± 2.0 yr). Body composition was analyzed by bone densitometry, and indirect calorimetry and cycle ergometer were used to calculate V˙O2peak (m
L·kg−1·min−1) and MPO (W) during an incremental exercise test. Sample was divided by pubertal status.
Results In the prepubertal group, LM and %FM acted independently as mediators in the relationship between bone mass and CRF or MPO (22%–25% for LM and 37%–50% for %FM, respectively). In pubertal children, LM acted as mediator at 37%.
Conclusions Although the independent mediator role of LM and %FM in the associations between CRF or MPO and bone mass was present during the prepubertal stage, only LM remain its mediator role in these associations during the postpubertal period. Therefore, with growth and sexual maturation, the full effect of LM seems to increase, whereas the influence of %FM seems to disappear.
Effects of Sleep Deprivation on Acute Skeletal Muscle Recovery after Exercise
01-02-2020 – DÁTTILO, MURILO; ANTUNES, HANNA KAREN MOREIRA; GALBES, NADINE MARQUES NUNES; MÔNICO-NETO, MARCOS; DE SÁ SOUZA, HELTON; DOS SANTOS QUARESMA, MARCUS VINÍCIUS LÚCIO; LEE, KIL SUN; UGRINOWITSCH, CARLOS; TUFIK, SERGIO; DE MELLO, MARCO TÚLIO
Purpose Sleep is considered essential for muscle recovery, mainly due to its effect on hormone secretion. Total sleep deprivation or restriction is known to alter not only blood hormones but also cytokines that might be related to skeletal muscle recovery. This study aimed to evaluate whether total sleep deprivation after eccentric exercise-induced muscle damage (EEIMD) modifies the profiles of blood hormones and cytokines.
Methods In two separate conditions, with a crossover and randomized model, 10 men (age, 24.5 ± 2.9 yr; body mass index, 22.7 ± 2.3 kg·m−2) performed a unilateral EEIMD protocol that comprised 240 eccentric contractions of the knee extensor muscles using an isokinetic dynamometer. In one condition, a “muscle damage” protocol was followed by 48 h of total sleep deprivation and 12 h of normal sleep (DEPRIVATION). In the other condition, the same muscle damage protocol was conducted, followed by three nights of regular sleep (SLEEP). Isometric muscle voluntary contraction tests and blood samples were collected serially throughout the protocol and analyzed for creatine kinase, free and total testosterone, IGF-1, cortisol, tumor necrosis factor-alpha, interleukin (IL)-1beta, IL-6, receptor antagonist of IL-1 and IL-10.
Results Muscle voluntary contraction and serum creatine kinase increased equally over the study period in both conditions. From the cytokines evaluated, only IL-6 increased in DEPRIVATION. No differences were detected in testosterone levels between conditions, but IGF-1, cortisol, and cortisol/total testosterone ratio were higher in DEPRIVATION.
Conclusions Total sleep deprivation after EEIMD does not delay muscle strength recovery but modifies inflammatory and hormonal responses.
Hypoxic Training Is Beneficial in Elite Athletes
01-02-2020 – MILLET, GRÉGOIRE P.; BROCHERIE, FRANCK
No abstract available
Hypoxic Training Is Not Beneficial in Elite Athletes
01-02-2020 – SIEBENMANN, CHRISTOPH; DEMPSEY, JEROME A.
No abstract available
Epidemiology and Biostatistics: An Introduction to Clinical Research, 2nd Edition
No abstract available
Epidemiology: Beyond the Basics, 4th Edition
No abstract available
Effects of Instrument-assisted Soft Tissue Mobilization on Musculoskeletal Properties—Corrigendum
No abstract available