Medicine and Science in Sports and Exercise

Medicine and Science in Sports and Exercise

High-Intensity Physical Exercise in a Glioblastoma Patient under Multimodal Treatment

01-12-2019 – TROSCHEL, FABIAN M.; BRANDT, RALF; WIEWRODT, RAINER; STUMMER, WALTER; WIEWRODT, DOROTHEE

Introduction Glioblastoma multiforme (GBM) carries a strongly unfavorable prognosis despite intensive multidisciplinary therapy. Physical exercise is rarely offered to patients for fear of adverse events such as falls, epileptic seizures, or bleeding, despite little supporting evidence. Here, we report a study of high-level and long-term exercise in a GBM patient.
Methods A 33-yr-old male, diagnosed with a large cystic GBM, was included in our institution’s Personal Training Program after initial tumor resection and adjuvant radiochemotherapy. The program was designed to facilitate individual long-term high-intensity exercise. Supervised by a certified personal trainer, it consisted of at least four weekly training sessions and intermittent performance diagnostics. An activity tracker quantified training intensity.
Results In this setting, the patient exercised at high intensity without adverse events for 87 continuous weeks (21 months). He averaged 43.7 metabolic equivalent of task hours per week (MET·h·wk−1), well above the 75th percentile of healthy males the same age, while undergoing multiple surgeries, chemotherapy, and radiation therapy regimens. The patient completed two marathons averaging less than 5 min·km−1 both times, despite tumor progression. Performance diagnostics indicated a gain of fitness even during continuous GBM treatment. Due to multiple intraventricular lesions and increasing intracranial pressure, training was stopped 6 wk before the patient passed away 2 yr after initial diagnosis.
Conclusions This study demonstrates that high-intensity, long-term physical training regimens are feasible in GBM patients during full multidisciplinary therapy. In this patient, the exercise was pursued without adverse events and led to a gain of fitness despite tumor progression and intensive multiple therapies. We conclude that, in GBM patients, exercise regimens require further study instead of general discouragement.

Exercise Intensity Matters in Chronic Nonspecific Low Back Pain Rehabilitation

01-12-2019 – VERBRUGGHE, JONAS; AGTEN, ANOUK; STEVENS, SJOERD; HANSEN, DOMINIQUE; DEMOULIN, CHRISTOPHE; O. EIJNDE, BERT; VANDENABEELE, FRANK; TIMMERMANS, ANNICK

Journal Article

Introduction Exercise therapy (ET) is advocated as a treatment for chronic nonspecific low back pain (CNSLBP). However, therapy effect sizes remain low. In other chronic disorders, training at higher intensity has resulted in greater improvements on both general health related and disease specific outcomes compared to lower-intensity ET. Possibly, high-intensity training also improves effect sizes in CNSLBP.
Objective To compare the effects of a high-intensity ET program with a similar moderate-intensity ET program on disability, pain, function, exercise capacity, and abdominal/back muscle strength in persons with CNSLBP.
Methods In a randomized controlled trial, persons with CNSLBP performed a 12-wk ET program (24 sessions, 1.5 h per session, twice per week) at high-intensity training (HIT) or moderate-intensity training (MIT). Questionnaires to assess disability (Modified Oswestry Index MODI), pain intensity (Numeric Pain Rating Scale), and function (Patient Specific Functioning Scale), a cardiopulmonary exercise test to assess exercise capacity (V˙O2max, cycling time), and a maximum isometric muscle strength test to assess abdominal/back muscle strength (maximum muscle torque) were administered at baseline and after the training program.
Results Thirty-eight participants (HIT: n = 19, MIT: n = 19) were included (mean age, 44.1 yr, SD = 9.8, 12 males). Groups did not differ at baseline. Between group differences (P < 0.01) in favor of HIT were found for MODI, V˙O2max, and cycling time. Within group improvements (P < 0.01) were found in both groups on MODI (HIT:−64%, MIT:−33%), Numeric Pain Rating Scale (HIT, −56%; MIT, −39%), Patient-Specific Functioning Scale (HIT:+37%, MIT:+39%), V˙O2max (HIT:+14, MIT:+4%), cycling time (HIT:+18%, MIT:+13%), and back muscle strength (HIT:+10%, MIT:+14%).
Conclusions High-intensity training proved to be a feasible, well tolerated, and effective therapy modality in CNSLBP. Moreover, it shows greater improvements on disability and exercise capacity than a similar ET performed at moderate intensity.

Feasibility of Two High-Intensity Interval Training Protocols in Cancer Survivors

01-12-2019 – SCHLÜTER, KATHRIN; SCHNEIDER, JUSTINE; SPRAVE, TANJA; WISKEMANN, JOACHIM; ROSENBERGER, FRIEDERIKE

Purpose High-intensity interval training (HIIT) is a time-efficient and promising tool for enhancing physical fitness. However, there is lack of research concerning safety and feasibility of HIIT in cancer survivors. Therefore, two different HIIT protocols were investigated in terms of safety, feasibility, and acute exercise responses.
Methods Forty cancer survivors (20 breast and 20 prostate cancer survivors, 62.9 ± 9.2 yr, BMI 27.4 ± 3.9 kg·m−2, 6 to 52 wk after the end of primary therapy) completed a maximal cardiopulmonary exercise test and two HIIT protocols on a cycle ergometer: 10 × 1 min at peak power output (10 × 1) and 4 × 4 min at 85%–95% peak HR (4 × 4). Safety (adverse events), acute physiological responses (HR, blood lactate concentration) and acute psychological responses (RPE, enjoyment) were recorded.
Results No major but three minor adverse events occurred. Ninety-five percent of participants were able to complete each HIIT protocol. Estimated energy expenditure (159 ± 15 vs 223 ± 45 kcal, P < 0.001), HR (128 ± 20 vs 139 ± 18 bpm; P < 0.001), blood lactate concentration (5.4 ± 1.0 vs 5.9 ± 1.9 mmol·L−1; P = 0.035), and RPE legs/breathing (13.8 ± 2.0/13.1 ± 2.0 vs 14.6 ± 2.1/14.3 ± 2.0; P = 0.038/0.003) were significantly higher in the 4 × 4. Enjoyment did not differ between protocols (P = 0.301).
Conclusions The two HIIT protocols as single sessions appear safe and in the vast majority of breast and prostate cancer survivors after the end of primary therapy also feasible and enjoyable. The 4 × 4 elicited higher energy expenditure and higher cardio-circulatory and metabolic strain and might therefore be preferred if a high training stimulus is intended.

Medical Tent Utilization at 10-km Road Races: Injury, Illness, and Influencing Factors

01-12-2019 – BRESLOW, REBECCA G.; SHRESTHA, SWASTINA; FEROE, ALIYA G.; KATZ, JEFFREY N.; TROYANOS, CHRIS; COLLINS, JAMIE E.

Purpose To increase awareness of the need for coordinated medical care at 10-km races and to help direct future medical planning for these events.
Methods We related medical encounter data from nineteen 10-km road races to runner, race, and environmental characteristics. We quantified the most commonly used resources and described the disposition of runners in these encounters.
Results Across the 19 races and 90,265 finishers, there were 562 medical events for a cumulative incidence of 6.2 events per 1000 finishers (95% confidence interval, 5.7–6.8). Race size was associated with an increased incidence of medical events. Overall, the most common diagnosis was heat-related illness (1.6 per 1000 finishers), followed by musculoskeletal complaints (1.3 per 1000 finishers) and fluid–electrolyte imbalances (1.2 per 1000 finishers). For all diagnoses, runners with finishing times in the first performance quintile and in the fifth performance quintile had greater representation in the medical tent than mid-pack runners. Most runners were treated with supportive care, basic first aid, and oral rehydration. Ninety-four runners (1.0 per 1000 finishers) required ice water immersion for exertional heat stroke. There were low rates of hospital transport (0.2 per 1000 finishers), and no fatalities.
Conclusions In 10-km road races, injury rates are low compared with longer races in similar weather conditions. Common medical issues can be managed with basic resources in the on-site medical tent. Green flag start race conditions may not predict race safety with regard to exertional heat stroke risk. There were no deaths in nearly 100,000 finishers.

Cytokine and Sclerostin Response to High-Intensity Interval Running versus Cycling

01-12-2019 – KOUVELIOTI, ROZALIA; KURGAN, NIGEL; FALK, BAREKET; WARD, WENDY E.; JOSSE, ANDREA R.; KLENTROU, PANAGIOTA

Journal Article

Purpose This study examined whether the exercise-induced changes in inflammatory cytokines differ between impact and no-impact high-intensity interval exercise, and whether they are associated with postexercise changes in sclerostin.
Methods Thirty-eight females (n = 19, 22.6 ± 2.7 yr) and males (n = 19, 22.3 ± 2.4 yr) performed two high-intensity interval exercise trials in random order (crossover design): running on a treadmill and cycling on a cycle ergometer. Trials consisted of eight repetitions of 1 min running or cycling at ≥90% maximal heart rate, separated by 1 min passive recovery intervals. Blood was collected preexercise and 5 min, 1 h, 24 h, and 48 h postexercise, and it was analyzed for serum levels of interleukins (IL-1β, IL-6, and IL-10), tumor necrosis factor alpha (TNF-α), and sclerostin.
Results Inflammatory cytokines significantly increased over time in both sexes with some differences between trials. Specifically, IL-1β significantly increased from pre- to 5 min after both trials (23%, P < 0.05), IL-6 increased 1 h after both trials (39%, P < 0.05), IL-10 was elevated 5 min after running (20%, P < 0.05) and 1 h after both running and cycling (41% and 64%, respectively, P < 0.05), and TNF-α increased 5 min after running (10%, P < 0.05). Sclerostin increased 5 min after both trials, with a greater increase in males than that in females (62 vs 32 pg·m
L−1 in running, P = 0.018; 63 vs 30 pg·m
L−1 in cycling, P = 0.004). In addition, sclerostin was significantly correlated with the corresponding changes in inflammatory cytokines, and 34% of the variance in its postexercise gain score (Δ) was explained by sex and the corresponding gain scores in TNF-α, which was the strongest predictor.
Conclusion A single bout of either impact or no-impact high-intensity exercise induces changes in inflammatory cytokines, which are associated with the postexercise increase in sclerostin.

Impact of Exercise and Activity on Weight Regain and Musculoskeletal Health Post-Ovariectomy

01-12-2019 – SHERK, VANESSA D.; JACKMAN, MATTHEW R.; HIGGINS, JANINE A.; GILES, ERIN D.; FORIGHT, REBECCA M.; PRESBY, DAVID M.; CARPENTER, R. DANA; JOHNSON, GINGER C.; OLJIRA, ROBERA; HOUCK, JULIE A.; MACLEAN, PAUL S.

Journal Article

The purpose of this study was to determine whether obesity and/or exercise training alters weight regain and musculoskeletal health after ovariectomy (OVX). Female rats were fed high-fat diet (HFD) to reveal obesity-prone (OP) and obesity-resistant (OR) phenotypes. The OP and OR exercising (EX) and sedentary (SED) rats were calorically restricted to lose 15% of body weight using medium-fat diet. Rats were then maintained in energy balance for 8 wk before OVX. After OVX and a brief calorically limited phase, rats were allowed to eat ad libitum until body weight plateaued. Starting at weight loss, EX ran 1 h·d−1, 6 d·wk−1, 15 m·min−1. Energy intake, spontaneous physical activity (SPA), and total energy expenditure were evaluated at the end of weight maintenance pre-OVX, and at three time points post-OVX: before weight regain, during early regain, and after regain. Data are presented as mean ± SE. Exercise attenuated weight regain after OVX in OP only (OP-EX, 123 ± 10 g; OP-SED, 165 ± 12 g; OR-EX, 121 ± 6 g; OR-SED, 116 ± 6 g), which was primarily an attenuation of fat gain. The early post-OVX increase in energy intake explained much of the weight regain, and was similar across groups. Exercising improved bone strength, as did maintaining SPA. Group differences in muscle mitochondrial respiration were not significant. The large decrease in SPA due to OVX was persistent, but early weight regain was dependent on decreased SPA. In conclusion, leanness and exercise do not necessarily protect from OVX-induced weight gain. Exercise prevented weight gain in obese rats, but loss of SPA was the greatest contributor to post-OVX weight gain. Thus, understanding the mechanisms resulting in reduction in SPA after ovarian hormone loss is critical in the prevention of menopause-associated metabolic dysfunction.

Area-level Socioeconomic Environment and Cardiorespiratory Fitness in Youth

01-12-2019 – CLENNIN, MORGAN N.; DOWDA, MARSHA; SUI, XUEMEI; PATE, RUSSELL R.

Introduction Cardiorespiratory fitness is one of the most important markers of cardiometabolic health and is a strong predictor of cardiovascular disease and all-cause mortality across the lifespan. However, little is known regarding the relationship of area-level socioeconomic environment on cardiorespiratory fitness during childhood and adolescence.
Purpose To examine the relationship between area-level socioeconomic environment and cardiorespiratory fitness in a diverse sample of school-age youth; and to determine the extent to which grade level, sex, race/ethnicity, and student poverty status moderate this relationship.
Methods South Carolina Fitness
Gram data for school year 2015 to 2016 were obtained for 44,078 youth. Cardiorespiratory fitness was determined using Progressive Aerobic Cardiovascular Endurance Run or 1-mile run/walk test. Area-level socioeconomic environment was expressed as a composite index score at the census tract level using data from the American Community Survey. Multilevel logistic regression analyses were conducted, controlling for individual-level characteristics and nesting within schools and districts. Interaction terms were then introduced to the model to examine their effect of multiple sociodemographic moderators.
Results Approximately half of the sample had inadequate cardiorespiratory fitness for health. The odds of achieving the Healthy Fitness Zone for cardiorespiratory fitness decreased by approximately 25% to 34% with increasing deprivation of the area-level socioeconomic environment, after controlling for covariates. The association between area-level socioeconomic environment and cardiorespiratory fitness also varied significantly by sex, grade level, and race/ethnicity subgroups.
Conclusions Cardiorespiratory fitness was positively associated with area-level socioeconomic environment; however, the relationship varied by demographic characteristics. These results highlight the importance of examining the influence of area-level socioeconomic environment on health across the life span. Additional research is needed to explore how area-level socioeconomic environment may impact evidence-based efforts to improve youth cardiorespiratory fitness levels.

Correlates of Children’s Physical Activity: A Canadian Multisite Study

01-12-2019 – LAROUCHE, RICHARD; BLANCHETTE, SÉBASTIEN; FAULKNER, GUY; RIAZI, NEGIN; TRUDEAU, FRANÇOIS; TREMBLAY, MARK S.

Journal Article

Purpose To inform future physical activity (PA) interventions among children, we investigated the correlates of PA among 8- to 12-yr-olds in three regions of Canada: Ottawa, Trois-Rivières, and Vancouver.
Methods We recruited 1699 children (55.0% girls) in 37 schools located in urban, suburban, and rural areas that differed in socioeconomic status. Children wore a sealed SC-Step
Rx pedometer capable of measuring moderate- to vigorous-intensity physical activity (MVPA) for seven consecutive days. Children and one of their parents/guardians completed a questionnaire that captured multiple potential PA correlates. Publicly available data on weather and neighborhood walkability were obtained. Multiply-imputed gender-stratified linear mixed models were used to examine the correlates of daily step counts and MVPA while controlling for age, site, type of urbanization, and area-level socioeconomic status.
Results Each additional hour spent outdoors was associated with higher PA in boys (+769 steps per day; +3.7 min MVPA per day) and girls (+596 steps per day; +3.5 min·d−1). Boys’ PA declined with age (−500 steps per day; −3.7 min·d−1). Boys were less active if they had a long-standing injury/illness (−1862 steps per day; −3.7 min·d−1) or their parents reported driving to work (−835 steps per day; −4.4 min·d−1), were worried about traffic (−982 steps per day; −6.4 min·d−1), or about other people in their neighborhood (−1250 steps per day). Girls speaking neither English nor French at home were less active (−620 steps per day; −3.7 min·d−1). In girls, each degree Celsius increase in morning temperature was associated with 77 additional steps per day, and each kilometer increase in active school travel distance was associated with 0.5 more MVPA minutes per day.
Conclusion Consistent with previous studies, our results suggest that PA interventions should aim to increase outdoor time. The observed gender differences in PA correlates suggest the need for a gender-sensitized approach to PA promotion.

Estimated Cardiorespiratory Fitness and Risk of Atrial Fibrillation: The Nord-Trøndelag Health Study

01-12-2019 – GARNVIK, LARS E.; MALMO, VEGARD; JANSZKY, IMRE; WISLØFF, ULRIK; LOENNECHEN, JAN P.; NES, BJARNE M.

Journal Article

Purpose To investigate the association between estimated cardiorespiratory fitness (e
CRF) and risk of atrial fibrillation (AF), and examine how long-term changes in e
CRF affects the AF risk.
Methods This prospective cohort study includes data of 39,844 men and women from the HUNT2 (August 15, 1995 to June 18, 1997) and the HUNT3 study (October 3, 2006 to June 25, 2008). The follow-up period was from HUNT3 until AF diagnosis or November 30, 2015. The AF diagnoses were retrieved from hospital registers and validated by medical doctors. A nonexercise test based on age, waist circumference, resting heart rate and self-reported physical activity was used to estimate CRF. Cox regression was performed to assess the association between e
CRF and AF.
Results The mean age was 50.6 ± 14.6 yr for men and 50.2 ± 15.2 yr for women. Mean follow-up time was 8.1 yr. One thousand fifty-seven cases of AF were documented. For men, the highest risk reduction of AF was 31% in the fourth quintile of e
CRF when compared with the first quintile (hazard ratio HR, 0.69; 95% confidence interval CI, 0.53–0.89). For women, the highest risk reduction was 47% in the fifth quintile when compared with the first quintile (HR, 0.53; 95% CI, 0.38–0.74). One metabolic equivalent increase in e
CRF over a 10-yr period was associated with 7% lower risk of AF (HR, 0.93; 95% CI, 0.86–1.00). Participants with improved e
CRF had 44% lower AF risk compared with those with decreased e
CRF (HR, 0.56; 95% CI, 0.36–0.87).
Conclusions The e
CRF was inversely associated with AF, and participants with improved e
CRF over a 10-yr period had less risk of AF. These findings support the hypothesis that fitness may prevent AF.

Risk Estimates for Diabetes and Hypertension with Different Physical Activity Methods

01-12-2019 – STERNFELD, BARBARA; GABRIEL, KELLEY PETTEE; JIANG, SHENG-FANG; WHITAKER, KARA M.; JACOBS, DAVID R. JR; QUESENBERRY, CHARLES P. JR; CARNETHON, MERCEDES; SIDNEY, STEPHEN

Journal Article

Purpose To estimate risks of incident type 2 diabetes (T2D) and stage 2 and greater hypertension associated with self-reported and accelerometer-determined moderate-vigorous physical activity (MVPA) separately and adjusted for each other.
Methods The sample included 2291 black and white men and women, ages 38–50 yr, in the Coronary Artery Risk Development in Young Adults (CARDIA) fitness study, conducted during the year 20 core CARDIA examination. Accelerometer-determined (Actigraph, LLC. model 7164) MVPA (MVPA-Acc), assessed at year 20, was defined as minutes per day of counts ≥2020 min−1. Self-reported MVPA (MVPA-SR) was assessed at year 20 using the CARDIA Physical Activity History. Incident T2D was ascertained at years 25 and 30 from fasting glucose, 2 h glucose tolerance test, Hb
A1c, or diabetes medication; incident hypertension was ascertained at those same times from measured blood pressure or use of antihypertensive medications. Modified Poisson regression models estimated relative risk (RR) of incident (years 25 and 30) T2D or hypertension, associated with middle and high tertiles of year 20 MVPA-Acc alone, year 20 MVPA-SR alone, and both, adjusted for each other, relative to bottom tertile.
Results In men, MVPA-Acc, but not MVPA-SR, was associated with a 37% to 67% decreased risk of incident T2D in a dose–response relation that persisted with adjustment for BMI, Similar associations were observed in women, although the risk reduction was similar in the second and third tertiles, relative to the bottom tertile. In both men and women, MVPA-Acc was marginally associated with reduced risk of incident stage 2 and greater hypertension, but only after adjustment for BMI, whereas MVPA-SR was not associated in either sex.
Conclusions Accelerometer-determined MVPA may provide more consistent risk estimates for incident diabetes than self-reported MVPA.

No Benefit of Ingestion of a Ketone Monoester Supplement on 10-km Running Performance

01-12-2019 – EVANS, MARK; MCSWINEY, FIONN T.; BRADY, AIDAN J.; EGAN, BRENDAN

Purpose Preexercise ingestion of exogenous ketones alters the metabolic response to exercise, but effects on exercise performance have been equivocal.
Methods On two occasions in a double-blind, randomized crossover design, eight endurance-trained runners performed 1 h of submaximal exercise at approximately 65% V˙O2max immediately followed by a 10-km self-paced time trial (TT) on a motorized treadmill. An 8% carbohydrate-electrolyte solution was consumed before and during exercise, either alone (CHO + PLA), or with 573 mg·kg−1 of a ketone monoester supplement (CHO + KME). Expired air, HR, and RPE were monitored during submaximal exercise. Serial venous blood samples were assayed for plasma glucose, lactate, and β-hydroxybutyrate concentrations.
Results CHO + KME produced plasma β-hydroxybutyrate concentrations of approximately 1.0 to 1.3 m
M during exercise (P < 0.001), but plasma glucose and lactate concentrations were similar during exercise in both trials. V˙O2, running economy, respiratory exchange ratio, HR, and RPE were also similar between trials. Performance in the 10-km TT was not different (P = 0.483) between CHO + KME (mean, 2402 s; 95% confidence interval, 2204–2600 s) and CHO + PLA (mean, 2422 s; 95% confidence interval, 2217–2628 s). Cognitive performance, measured by reaction time and a multitasking test, did not differ between trials.
Conclusions Compared with carbohydrate alone, coingestion of KME by endurance-trained athletes elevated plasma β-hydroxybutyrate concentrations, but did not improve 10-km running TT or cognitive performance.

Extended Sleep Maintains Endurance Performance Better than Normal or Restricted Sleep

01-12-2019 – ROBERTS, SPENCER S. H.; TEO, WEI-PENG; AISBETT, BRAD; WARMINGTON, STUART A.

Journal Article

Purpose The cumulative influence of sleep time on endurance performance remains unclear. This study examined the effects of three consecutive nights of both sleep extension (SE) and sleep restriction (SR) on endurance cycling performance.
Methods Endurance cyclists/triathletes (n = 9) completed a counterbalanced crossover experiment with three conditions: SR, normal sleep (NS), and SE. Each condition comprised seven days/nights of data collection (−2, −1, D1, D2, D3, D4, and +1). Sleep was monitored using actigraphy throughout. Participants completed testing sessions on days D1–D4 that included an endurance time-trial (TT), mood, and psychomotor vigilance assessment. Perceived exertion (RPE) was monitored throughout each TT. Participants slept habitually before D1; however, time in bed was reduced by 30% (SR), remained normal (NS), or extended by 30% (SE) on nights D1, D2, and D3. Data were analyzed using generalized estimating equations.
Results On nights D1, D2, and D3, total sleep time was longer (P 8 h per night to optimize performance.

Improving the Diagnosis of Nonfunctional Overreaching and Overtraining Syndrome

01-12-2019 – BUYSE, LUK; DECROIX, LIESELOT; TIMMERMANS, NIELS; BARBÉ, KURT; VERRELST, RUTH; MEEUSEN, ROMAIN

Journal Article

Introduction This study aimed to simplify and optimize the distinction between nonfunctional overreaching (NFO) and overtraining syndrome (OTS) by developing a multivariate approach (discriminant analysis DA) including hormonal and psychological changes measured during the Training Optimization (TOP) test.
Methods Sensitivity of previously defined cutoff values for hypothalamic–pituitary–adrenal axis hormonal changes were recalculated on a larger database (n = 100). Discriminant analysis including hormonal and psychological variables measured during the TOP test was used to discriminate between NFO and OTS and predict the diagnosis of new cases.
Results Adrenocorticotrophic hormone (ACTH) and prolactin (PRL) responses to the second exercise test were most sensitive to NFO and OTS. Cutoff values for ACTH and PRL response to the second test (NFO > cutoff value (200%) > OTS), showed a sensitivity of 67% for ACTH and 93% for PRL in case of OTS and 74% for both ACTH and PRL in case of NFO. A DA including hormonal and psychological changes measured during the TOP test, resulted in the accurate diagnosis of NFO and OTS with 98% sensitivity. The ACTH and PRL responses to the first and second exercise tests and feeling of fatigue were the most discriminating variables.
Conclusions The ACTH and PRL responses during the TOP test are the most sensitive markers to discriminate between NFO and OTS. Discriminant analysis including hormonal and psychological responses during the TOP test, can be used to optimize the diagnosis of NFO and OTS.

Lower Trapezius Weakness and Shoulder Complex Biomechanics during the Tennis Serve

01-12-2019 – GILLET, BENOIT; ROGOWSKI, ISABELLE; MONGA-DUBREUIL, ELODIE; BEGON, MICKAËL

Journal Article

Purpose This study aimed to assess the effect of lower trapezius (LT) weakness on humeral and scapular kinematics and shoulder muscle activity during the tennis serve.
Methods Fifteen competitive male tennis players (age, 23.8 ± 3.4 yr; height, 182.8 ± 6.7 cm; mass: 76.6 ± 8.7 kg; tennis experience: 15.6 ± 4.9 yr) performed two tennis serves before and after selective fatigue of the LT (25-min electric muscle stimulation). During each tennis serve, racket, humeral and scapular kinematics and the activity of 13 shoulder muscles were recorded using an optoelectronic system synchronized with indwelling and surface electromyography. The serve was split into five phases, that is, early and late cocking, acceleration, early and late follow-through.
Results Selective fatigue led to a 22.5% ± 10.4% strength decrease but did not alter maximum racket speed and humerothoracic joint kinematics. However, increased scapular upward rotation was observed in the acceleration (P = 0.02) and early follow-through (P = 0.01) phases. Decreased muscular activity was observed during the early cocking phase for the LT (P = 0.01), during the acceleration phase for the LT (P = 0.01), anterior deltoid (P = 0.03), pectoralis major (P = 0.04), and subscapularis (P = 0.03), and during the early follow-through phase for the anterior deltoid (P = 0.03) and LT (P = 0.04).
Conclusions The LT weakness altered neither serve velocity nor humerothoracic joint kinematics, but impaired scapulothoracic kinematics and anterior shoulder muscle activation. Such alterations may reduce the subacromial space and jeopardize humeral head stability. These findings shed new light on the consequences of LT weakness, highlighting the importance of monitoring and strengthening this muscle in overhead athletes.

Load Carriage and Physical Exertion Influence Cognitive Control in Military Scenarios

01-12-2019 – GILES, GRACE E.; HASSELQUIST, LEIF; CARUSO, CHRISTINA M.; EDDY, MARIANNA D.

Journal Article

Introduction Physical exertion has both beneficial and detrimental effects on cognitive performance, particularly cognitive control. Research into physical exertion under conditions of load carriage is particularly important given that military personnel and first responders must perform optimally under such combinatorial physical stressors. The present work sought to characterize cognitive control as a function of physical exertion and load carriage in a military operational scenario.
Methods Thirty-one active-duty soldiers underwent a 4-h operationally relevant and fatiguing scenario that included two 1-h foot marches under load carriage conditions of 8.8, 47.2, 50.7 kg on each of three separate days. During each foot march, they completed five 5-min blocks of an auditory go/no-go task of response inhibition.
Results Results showed that response inhibition declined with increasing load carriage and physical exertion, as evidenced by lower proportion of correct responses, higher proportion of false alarms, and lower response sensitivity between all three load conditions, particularly upon successive foot marches and time blocks within each foot march.
Conclusions The results support previous laboratory-based work on load carriage and physical exertion and suggest that deteriorations in cognitive control witnessed in laboratory settings are more pronounced within realistic operational scenarios akin to those encountered by military personnel and first responders.

Commentary on Motorsport and Driver-Athlete Research

01-12-2019 – POTKANOWICZ, EDWARD S.

No abstract available

The Physiology of Auto Racing

01-12-2019 – REID, MICHAEL B.; LIGHTFOOT, J. TIMOTHY

Journal Article

Introduction Auto racing poses a unique set of physiologic challenges for athletes who compete in this sport. These challenges are not widely recognized due to the limited amount of original research in this field and the diffuse nature of this literature. The purpose of this article is to review the major physiologic challenges of auto racing and summarize what is currently known about athletes in this sport.
Conclusions The physical stressors of either driving or servicing the race car are overlaid with particular environmental challenges associated with racing (e.g., thermal, noise, carbon monoxide exposure) that increase the physiological stress on motorsport athletes. Physical stress reflects the muscular work required for car control and control of posture during high gravitational (g) loads: factors that predispose athletes to fatigue. The physiologic effects of these stressors include cardiovascular stress as reflected by prolonged elevation of heart rate, cardiac output, and oxygen consumption in both driver and pit athletes during competition. Psychological stress is evident in autonomic and endocrine responses of athletes during competition. The thermal stress of having to compete wearing multilayer fire suits and closed helmets in ambient temperatures of 50°C to 60°C results in the ubiquitous risk of dehydration. Published data show that both drivers and pit crew members are accomplished athletes with distinct challenges and abilities. There are gaps in the literature, especially in regard to female, older adult, and child participants. Additionally, minimal literature is available on appropriate training programs to offset the physiological challenges of auto racing.

V˙O2peak, Body Composition, and Neck Strength of Elite Motor Racing Drivers

01-12-2019 – MCKNIGHT, PETER J.; BENNETT, LUKE A.; MALVERN, JON J.; FERGUSON, DAVID P.

Journal Article

Purpose Automobile racing is widely known to be physically demanding; however, there is no published information comparing the physical fitness variables of elite-level race car drivers across various competitive championships.
Methods We documented the body composition, peak oxygen consumption (V˙O2peak), and isometric neck strength in a sample of elite race car drivers currently competing in Formula 1, Indy
Car, NASCAR, and International Motor Sports Association sports car racing (IMSA GTD), to determine current human performance benchmarks and establish goals for drivers wishing to compete in these series.
Results Percent body fat was significantly (P < 0.001) lower in Formula 1 drivers (8.1% ± 1.7%) as compared with the other series, with Indy
Car (17.4% ± 1.7%) and NASCAR (17.3% ± 4.6%) being less than IMSA GTD (24.9% ± 1.8%). Percent lean mass followed the same trend as percent body fat. IMSA GTD had not only the highest percent body fat but also the lowest (P = 0.001) V˙O2peak (45.2 ± 2.1 m
L·kg−1·m
L−1) compared with Formula 1 (62.0 ± 6.0 m
L·kg−1·m
L−1), Indy
Car (58.05 ± 6.40 m
L·kg−1·m
L−1), and NASCAR (53.2 ± 4.1 m
L·kg−1·m
L−1). Isometric neck strength was the highest in Formula 1 and Indy
Car drivers as compared with IMSA GTD and NASCAR drivers.
Conclusion These results support the hypothesis that the varying physical demands of each competition series require different physical fitness levels of drivers. These benchmarks can be used by exercise professionals to better prepare athletes for competition.

Physiological Responses of Male and Female Race Car Drivers during Competition

01-12-2019 – FERGUSON, DAVID P.; BARTHEL, SAMUEL C.; PRUETT, MONTANA L.; BUCKINGHAM, TODD M.; WAASO, PEYTON R.

Journal Article

Automobile racing is one of the largest spectator sports in the world with male and female drivers competing together. Popular media has speculated on the relative capabilities of males and females in automobile racing, yet there are no scientific investigations examining physiological responses to racing among males and females.
Purpose 1) To evaluate the physiological responses of male and female drivers in open and closed cockpit race cars, 2) to examine the moderating influence of menstrual cycle phase on physiological responses to racing among female drivers.
Methods HR, breathing rate, skin temperature, core temperature, and Physiological Strain Index (PSI) were measured using the Equivital Life Monitor in male (n = 6) and female (n = 6) drivers at three races in open or closed cockpit cars. Among females, menstrual cycle phase for each race was recorded.
Results During racing conditions there was no difference (P > 0.05) between male and female drivers for HR, skin temperature, core temperature, or PSI. The female drivers had a higher (P < 0.001) breathing rate compared with the male drivers. Compared with the follicular phase, the luteal phase had an increased (P < 0.001) HR, breathing rate, skin temperature, core temperature, and PSI. The closed cockpit cars elicited (P < 0.001) a higher skin temperature, core temperature and PSI as compared with the open cockpit cars.
Conclusions There were no differences in the physiological responses to automobile racing between male and female drivers. The luteal phase elicited higher physiological responses than the follicular phase, but was not different from the male drivers. Thereby, practitioners should focus on reducing stresses induced by a closed cockpit race car as opposed to the menstrual cycle.

Resistance Exercise–induced Changes in Muscle Phenotype Are Load Dependent

01-12-2019 – LIM, CHANGHYUN; KIM, HYO JEONG; MORTON, ROBERT W.; HARRIS, ROGER; PHILLIPS, STUART M.; JEONG, TAE SEOK; KIM, CHANG KEUN

Journal Article

Introduction Lower-load (LL), higher-repetition resistance exercise training (RET) can increase muscle mass in a similar degree as higher-load (HL), lower-repetition RET. However, little is known about how LL and HL RET modulate other aspects of the RET phenotype such as satellite cells, myonuclei, and mitochondrial proteins. We aimed to investigate changes in muscle mass, muscle strength, satellite cell activity, myonuclear addition, and mitochondrial protein content after prolonged RET with LL and HL RET.
Methods We recruited 21 young men and randomly assigned them to perform 10 wk RET (leg press, leg extension, and leg curl) three times per week with the following conditions: 80FAIL (80% one-repetition maximum 1RM performed to volitional fatigue), 30WM (30%1RM with volume matched to 80FAIL), and 30FAIL (30%1RM to volitional fatigue). Skeletal muscle biopsies were taken from the vastus lateralis pre- and post-RET intervention.
Results After 10 wk of RET, only 30FAIL and 80FAIL showed an increase in peak torque and type I fiber cross-sectional area (P < 0.05). Moreover, only 30FAIL resulted in a significant decrease in the myonuclear domain of type II muscle fibers and an increase in mitochondrial proteins related to autophagy, fission, and fusion (all P < 0.05).
Conclusion We discovered that LL RET was effective at increasing the content of several mitochondrial proteins. Similar to previous research, we found that changes in muscle mass and strength were independent of load when repetitions were performed to volitional fatigue.

Fuel Use during Exercise at Altitude in Women with Glucose–Fructose Ingestion

01-12-2019 – O’HARA, JOHN P.; DUCKWORTH, LAUREN; BLACK, ALISTAIR; WOODS, DAVID R.; MELLOR, ADRIAN; BOOS, CHRISTOPHER; GALLAGHER, LIAM; TSAKIRIDES, COSTAS; ARJOMANDKHAH, NICOLA C.; MORRISON, DOUGLAS J.; PRESTON, THOMAS; KING, RODERICK F. G. J.

Journal Article

Purpose This study compared the coingestion of glucose and fructose on exogenous and endogenous substrate oxidation during prolonged exercise at terrestrial high altitude (HA) versus sea level, in women.
Method Five women completed two bouts of cycling at the same relative workload (55% Wmax) for 120 min on acute exposure to HA (3375 m) and at sea level (~113 m). In each trial, participants ingested 1.2 g·min−1 of glucose (enriched with 13C glucose) and 0.6 g·min−1 of fructose (enriched with 13C fructose) before and every 15 min during exercise. Indirect calorimetry and isotope ratio mass spectrometry were used to calculate fat oxidation, total and exogenous carbohydrate oxidation, plasma glucose oxidation, and endogenous glucose oxidation derived from liver and muscle glycogen.
Results The rates and absolute contribution of exogenous carbohydrate oxidation was significantly lower at HA compared with sea level (effect size ES > 0.99, P < 0.024), with the relative exogenous carbohydrate contribution approaching significance (32.6% ± 6.1% vs 36.0% ± 6.1%, ES = 0.56, P = 0.059) during the second hour of exercise. In comparison, no significant differences were observed between HA and sea level for the relative and absolute contributions of liver glucose (3.2% ± 1.2% vs 3.1% ± 0.8%, ES = 0.09, P = 0.635 and 5.1 ± 1.8 vs 5.4 ± 1.7 g, ES = 0.19, P = 0.217), and muscle glycogen (14.4% ± 12.2% vs 15.8% ± 9.3%, ES = 0.11, P = 0.934 and 23.1 ± 19.0 vs 28.7 ± 17.8 g, ES = 0.30, P = 0.367). Furthermore, there was no significant difference in total fat oxidation between HA and sea level (66.3 ± 21.4 vs 59.6 ± 7.7 g, ES = 0.32, P = 0.557).
Conclusions In women, acute exposure to HA reduces the reliance on exogenous carbohydrate oxidation during cycling at the same relative exercise intensity.

New On-Water Test for the Assessment of Blood Lactate Response to Exercise in Elite Kayakers

01-12-2019 – PILOTTO, ANDREA M.; RASICA, LETIZIA; SCALISE, GABRIELE; ANNONI, STEFANO; LA TORRE, ANTONIO; MARZORATI, MAURO; PORCELLI, SIMONE

Journal Article

Purpose Lactate thresholds are physiological parameters used to train athletes and monitor performance or training. Currently, the assessment of lactate thresholds in kayakers is performed in a laboratory setting utilizing specific ergometers; however, laboratory tests differ from on-water evaluation for several reasons. The aim of this study was to assess reliability and validity of a new on-water incremental test for the assessment of blood lactate response to exercise in flat-water kayakers. Maximal lactate steady state test (MLSS) was used as criterion measurement.
Methods Eleven junior (16.5 ± 1.9 yr) élite flat-water kayakers performed: i) an incremental cardiopulmonary test up to voluntary exhaustion on a stationary kayak ergometer to determine peak oxygen uptake; ii) an on-water 1000‐m distance trial (T1000) to record best performance time and average speed (S1000); iii) two repetitions of on-water incremental kayaking test (WIK test); iv) several repetitions of on-water constant speed tests to determine MLSS. Speed, HR, and blood lactate concentrations were determined during on-water tests.
Results The best performance time in T1000 was 262 ± 13 s, corresponding to an S1000 of 3.82 ± 0.19 m·s−1. Lactate threshold determined by modified Dmax method (LTDmod) during WIK test was 2.78 ± 1.02 mmol·L−1 and the corresponding speed (SLT) was 3.34 ± 0.16 m·s−1. Test–retest reliability, calculated on SLT, was strong (ICC = 0.95 and r = 0.93). MLSS test corresponded to 3.06 ± 0.68 mmol·L−1 and was reached at a speed (SMLSS) of 3.36 ± 0.14 m·s−1. Correlation coefficient between SLT and SMLSS was 0.90 (P = 0.0001). Interestingly, a significant correlation (r = 0.96, P < 0.0001) was observed between SLT and S1000.
Conclusions The WIK test showed good reliability and validity for the assessment of speed corresponding to LTDmod in flat-water kayakers and it could be a useful tool to monitor athletic performance. The speed value at LTDmod nicely predicted performance on 1000 m.

Reduced Active Muscle Stiffness after Intermittent Submaximal Isometric Contractions

01-12-2019 – MOREL, BAPTISTE; HUG, FRANÇOIS; NORDEZ, ANTOINE; POURNOT, HERVÉ; BESSON, THIBAULT; MATHEVON, LAURE; LAPOLE, THOMAS

Journal Article

Purpose Whether muscle stiffness is influenced by fatigue remains unclear. Classical methods used to assess muscle stiffness provide a global measure at the joint level. As fatigue may selectively affect specific muscles, a joint-level approach may not be sensitive enough to detect potential changes in muscle stiffness. Taking advantage of ultrasound shear wave elastography, this study aimed to determine the influence of a fatiguing protocol involving intermittent submaximal isometric contractions on muscle shear modulus (an index of stiffness).
Methods Shear modulus was measured on either the vastus lateralis (n = 9) or the abductor digiti minimi (n = 10) before and after 15 min of intermittent submaximal isometric contractions at 60% of maximal voluntary contraction (MVC) (4 s ON, 4 s OFF). An index of active muscle stiffness was estimated PRE- and POST-fatigue as the slope of the linear regression established between shear modulus and absolute joint force up to 60% MVC.
Results After the fatiguing exercise, MVC was significantly decreased by 22% ± 7% and 32% ± 15% for knee extension and little finger abduction, respectively (P < 0.001). When compared to PRE-fatigue, the index of active muscle stiffness was 12% ± 15% lower for the vastus lateralis (P < 0.031) and 44% ± 19% lower for the abductor digiti minimi (P < 0.001) POST-fatigue.
Conclusions Although the present results cannot clearly determine the involved mechanisms, they demonstrate a decreased active muscle stiffness after a fatiguing task involving intermittent submaximal isometric contractions. Further studies should now determine whether this change in stiffness affects performance and risk of injury.

Methodological Recommendations for Menstrual Cycle Research in Sports and Exercise

01-12-2019 – JANSE DE JONGE, XANNE; THOMPSON, BELINDA; HAN, AHREUM

Journal Article

Introduction The aim of this review is to provide methodological recommendations for menstrual cycle research in exercise science and sports medicine based on a review of recent literature. Research in this area is growing but often reports conflicting results, and it is proposed that some of this may be explained by methodological issues.
Methods This review examined the menstrual cycle verification methods used in recent literature on exercise performance over the menstrual cycle identified through a literature search of PubMed and Sport
Discus from 2008 until 2018.
Results Potential changes over the menstrual cycle are likely related to hormone fluctuations; however, only 44% of the selected studies measured the actual concentrations of the female steroid hormones estrogen and progesterone. It was shown that the likely inclusion of participants with anovulatory or luteal phase–deficient cycles in combination with small participant numbers has affected results in recent menstrual cycle research and, consequently, our understanding of this area.
Conclusion To improve the quality of future menstrual cycle research, it is recommended that a combination of three methods is used to verify menstrual cycle phase: the calendar-based counting method combined with urinary luteinizing hormone surge testing and the measurement of serum estrogen and progesterone concentrations at the time of testing. A strict luteal phase verification limit of >16 nmol·L−1 for progesterone should be set. It is also recommended that future research should focus on the inclusion of the late follicular estrogen peak. It is envisaged that these methodological recommendations will assist in clarifying some of the disagreement around the effects of the menstrual cycle on exercise performance and other aspects of exercise science and sports medicine.

The Way Things Stand

01-12-2019 – Stoner, Lee; Barone Gibbs, Bethany

No abstract available

Response

01-12-2019 – Betts, James A.; Thompson, Dylan; Gonzalez, Javier T.; Afman, Gregg H.

No abstract available

Reconstructive Foot and Ankle Surgery: Management of Complications, 3rd Edition

01-12-2019 –

No abstract available

Physical Activity Instruction of Older Adults, 2nd Edition

01-12-2019 –

No abstract available