Medicine and Science in Sports and Exercise

Medicine and Science in Sports and Exercise

Physiological Evaluation for Endurance Exercise Prescription in Sickle Cell Disease

01-09-2019 – MESSONNIER, LAURENT A.; GELLEN, BARNABAS; LACROIX, ROXANE; PEYROT, SANDRINE; RUPP, THOMAS; MIRA, JOSÉ; PEYRARD, ARTHUR; BERKENOU, JUGURTHA; GALACTÉROS, FRÉDÉRIC; BARTOLUCCI, PABLO; FÉASSON, LÉONARD

Journal Article

Purpose Although strenuous exercise may expose sickle cell disease (SCD) patients to risks of vaso-occlusive crisis, evidence suggests that regular endurance exercise may be beneficial. This study aimed to test (i) the safety and usefulness of a submaximal incremental exercise in evaluating physical ability of SCD patients and identify a marker for the management of endurance exercise and (ii) the feasibility of endurance exercise sessions in SCD patients.
Methods Twenty adults with SCD (12 men and 8 women) performed a submaximal incremental exercise used to determine the first lactate threshold (LT1) and stopped as soon as blood lactate concentration (lactateb) reached ≥4 mmol·L−1. Fifteen of those patients (8 men and 7 women) also performed three 30-min endurance exercise sessions at ~2.5 mmol·L−1 of lactateb on separate occasions.
Results LT1 occurred at 47 ± 3 and 33 ± 3 W for men and women, respectively, demonstrating the extreme deconditioning and, thus, low physical ability of adult SCD patients. During endurance exercise, peripheral oxygen saturation and lactateb most often remained stable and within acceptable ranges.
Conclusions The proposed strategy of submaximal incremental exercise allowed safe determination of LT1, an important parameter of patients’ physical ability. The study also demonstrated the feasibility and safety of individually tailored endurance exercises at ~2.5 mmol·L−1 of lactateb. These latter results suggest that endurance training programs may be considered for adult SCD patients and that the method proposed here may be helpful in that regard.

Cardiopulmonary Profile of Individuals with Intellectual Disability

01-09-2019 – BOONMAN, ANNE J. N.; SCHROEDER, ELIZABETH C.; HOPMAN, MARIA T. E.; FERNHALL, BO; Hilgenkamp, THESSA I. M.

Journal Article

Introduction Individuals with intellectual disabilities (ID) are often sedentary and have low fitness levels. Current knowledge supports the existence of physiological barriers resulting in low fitness and exercise intolerance in individuals with Down syndrome, which might be applicable to other ID etiologies. If physiological barriers exist in ID, this would require adaptation of the physical activity guidelines.
Purpose The aim of this study was to assess differences in cardiopulmonary profiles, including maximal oxygen uptake, during a cardiopulmonary exercise test in individuals with ID without Down syndrome and healthy controls.
Methods Participants performed an incremental cardiopulmonary exercise test on a treadmill until exhaustion. Outcomes were peak heart rate (HRpeak), absolute peak oxygen uptake (V˙O2peak), relative V˙O2peak, peak minute ventilation, peak CO2 expenditure, oxygen uptake efficiency slope, V˙E/V˙CO2 slope, absolute O2 pulse, relative O2 pulse, difference from predicted HRpeak, HR reserve, RERpeak, ventilatory threshold (VT), and VT as a percentage of V˙O2peak. Differences between groups were analyzed with Student’s t-tests and multiple linear regression after adjusting for potential confounders (sex, age, body mass index, and activity level).
Results Individuals with ID had worse outcomes on all of the cardiopulmonary outcomes, except for VT expressed as a percentage of V˙O2peak and V˙E/V˙CO2 slope (P < 0.05). Having ID was an independent predictor of reduced physiologic function during exercise (P < 0.05).
Conclusion These results demonstrate that individuals with ID present exercise intolerance potentially related to lower HRpeak and impairments in ventilatory function, and these results also suggest the possibility of peripheral muscle hypoperfusion. Existing physical activity guidelines likely underestimate the actual intensity of activity performed by individuals with ID and need to be adapted.

Diverse Exercises Similarly Reduce Older Adults’ Mobility Limitations

01-09-2019 – TOLLÁR, JÓZSEF; NAGY, FERENC; MOIZS, MARIANN; TÓTH, BÉLA E.; SANDERS, LIANNE M. J.; HORTOBÁGYI, TIBOR

Journal Article

Introduction/Purpose Little is known about the comparative effectiveness of exercise programs, especially when delivered at a high intensity, in mobility-limited older adults. We compared the effects of 25 sessions of high-intensity agility exergaming (EXE) and stationary cycling (CYC) at the same cardiovascular load on measured and perceived mobility limitations, balance, and health-related quality of life in mobility-limited older adults.
Methods Randomized to EXE (n = 28) and CYC (n = 27), mobility-impaired older adults (age 70 yr) exercised five times per week for 5 wk at 80% of age-predicted maximal heart rate. Waitlisted controls did not exercise (n = 28).
Results Groups did not differ at baseline in any outcomes (P > 0.05). The primary outcomes (The Short Form-36-Health Survey: EXE, 6.9%; effect size, 2.2; CYC, 5.5%, 1.94; Western Ontario and Mc
Master Universities Osteoarthritis Index: EXE, −27.2%, −3.83; CYC, −17.2, −2.90) improved similarly (P > 0.05). Secondary outcomes, including body mass (−3.7%), depression (−18%), and walking capacity (13.5%) also improved (P 0.05).
Conclusions When matched for cardiovascular and perceived effort, two diverse high-intensity exercise programs improved health-related quality of life, perceived mobility limitation, and walking capacity similarly and balance outcomes more in mobility-limited older adults, expanding these older adults’ evidence-based exercise options to reduce mobility limitations.

Blood Flow–restricted Exercise Does Not Induce a Cross-Transfer of Effect: A Randomized Controlled Trial

01-09-2019 – AMPOMAH, KWASI; AMANO, SHINICHI; WAGES, NATHAN P.; VOLZ, LAUREN; CLIFT, RACHEL; LUDIN, ARIMI FITRI MAT; NAKAZAWA, MASATO; LAW, TIMOTHY D.; MANINI, TODD M.; THOMAS, JAMES S.; RUSS, DAVID W.; CLARK, BRIAN C.

Journal Article

Purpose The goal of this trial was to determine whether low-load blood flow–restricted (BFR) exercise of appendicular muscles induces a cross-transfer of effect to the trunk extensor (TE) muscles, such that low-load TE exercise would enhance TE size and function to a greater extent than standard low-load exercise in people with recurrent low back pain (LBP). We also investigated the direct effects of BFR exercise in the appendicular muscles.
Methods Thirty-two adults with recurrent, nonspecific LBP were randomized into two groups: Appendicular BFR exercise (BFR exercise) or control exercise (CON exercise). All participants trained (two times per week) for 10 wk, with a 12-wk follow-up. Participants performed three sets of leg extension (LE), plantar flexion (PF), and elbow flexion (EF) exercises followed by low-load TE exercise without BFR. Outcome measures included magnetic resonance imaging–derived muscle size (quadriceps and TE), strength (LE, PF, EF, and TE), and endurance (LE and TE).
Results There was no evidence for a cross-transfer of effect to the TE. There was also no statistically significant enhancement of limb skeletal muscle size or function of BFR relative to CON exercise at any time point; though, moderate effect sizes for BFR exercise were observed for enhanced muscle size and strength in the leg extensors.
Conclusions Low-load BFR exercise of the appendicular muscles did not result in a cross-transfer of effect to the TE musculature. There was also no significant benefit of low-load BFR exercise on the appendicular muscle size and function, suggesting no benefit from low-load BFR exercise in adults with recurrent, nonspecific LBP.

High-Frequency Stimulation on Skeletal Muscle Maintenance in Female Cachectic Mice

01-09-2019 – SATO, SHUICHI; GAO, SONG; PUPPA, MELISSA J.; KOSTEK, MATTHEW C.; WILSON, L. BRITT; CARSON, JAMES A.

Journal Article

Cancer cachexia, an unintentional body weight loss due to cancer, affects patients’ survival, quality of life, and response to chemotherapy. Although exercise training is a promising intervention to prevent and treat cancer cachexia, our mechanistic understanding of cachexia’s effect on contraction-induced muscle adaptation has been limited to the examination of male mice. Because sex can affect muscle regeneration and response to contraction in humans and mice, the effect of cachexia on the female response to eccentric contraction warrants further investigation.
Purpose The purpose of this study was to determine whether high-frequency electric stimulation (HFES) could attenuate muscle mass loss during the progression of cancer cachexia in female tumor-bearing mice.
Methods Female wild-type (WT) and Apc
Min/+ (Min) mice (16–18 wk old) performed either repeated bouts or a single bout of HFES (10 sets of 6 repetitions, ~22 min), which eccentrically contracts the tibialis anterior (TA) muscle. TA myofiber size, oxidative capacity, anabolic signaling, and catabolic signaling were examined.
Results Min had reduced TA muscle mass and type IIa and type IIb fiber sizes compared with WT. HFES increased the muscle weight and the mean cross-sectional area of type IIa and type IIb fibers in WT and Min mice. HFES increased m
TOR signaling and myofibrillar protein synthesis and attenuated cachexia-induced AMPK activity. HFES attenuated the cachexia-associated decrease in skeletal muscle oxidative capacity.
Conclusion HFES in female mice can activate muscle protein synthesis through m
TOR signaling and repeated bouts of contraction can attenuate cancer-induced muscle mass loss.

Kinetics of Left Ventricular Mechanics during Transition from Rest to Exercise

01-09-2019 – IZEM, OMAR; MAUFRAIS, CLAIRE; OBERT, PHILIPPE; RUPP, THOMAS; SCHUSTER, IRIS; NOTTIN, STÉPHANE

Journal Article

Purpose At the onset of physical exercise, oxygen (O2) transport adapts to meet the working muscle O2 demands. Cardiac output abruptly increases through the concomitant changes of HR and stroke volume (SV), which is conditioned by the left ventricular (LV) function. The purpose of this study was to investigate the contribution of many LV diastolic and systolic function parameters, including twist–untwist mechanics, to SV adaptation during the first minutes after exercise onset.
Methods Diastolic and systolic myocardial strains and twist were monitored by two-dimensional speckle-tracking echocardiography with high temporal resolution in 28 young men (mean age, 23 ± 4 yr) who performed five similar constant work-load exercises on a cycloergometer (target HR: 125 bpm). Two-dimensional cine-loops were recorded every 15 s during the first minute of exercise, and then every 30 s for the next 3 min.
Results During the first 60 s of exercise, SV (from 104 ± 15 m
L to 126 ± 21 m
L, P < 0.001) increased concomitantly with LV strain and strain rates. Early filling was the main SV determinant during this phase, probably linked to the increase of venous return (at the very beginning of exercise), LV relaxation (from 1.5 ± 0.3 s to 2.5 ± 0.4 s, P < 0.001) and untwisting (from −78 ± 34°·s−1 to −165 ± 61°·s−1, P < 0.001). After the first minute, SV remained constant, whereas LV untwisting continued to increase (from −165 ± 61°·s−1 to −187 ± 60°·s−1, P < 0.001) and the other systolic and diastolic parameters reached a plateau.
Conclusions This study gives new mechanical insights into LV kinetics to address the challenge of SV response at the onset of exercise.

Weight Training and Risk of 10 Common Types of Cancer

01-09-2019 – MAZZILLI, KAITLYN M.; MATTHEWS, CHARLES E.; SALERNO, ELIZABETH A.; MOORE, STEVEN C.

Journal Article

Introduction Ample data support that leisure time aerobic moderate to vigorous physical activity (MVPA) is associated with lower risk of at least seven types of cancer. However, the link between muscle-strengthening activities and cancer etiology is not well understood. Our objective was to determine the association of weight lifting with incidence of 10 common cancer types.
Methods We used multivariable Cox regression to estimate hazard ratios (HR) and 95% confidence intervals (CI) for association of weight lifting with incidence of 10 cancer types in the National Institutes of Health-American Association of Retired Persons Diet and Health Study follow-up. Weight lifting was modeled continuously and categorically. Dose–response relationships were evaluated using cubic restricted spline models. We explored whether associations varied by subgroups defined by sex, age, and body mass index using the Wald test for homogeneity. We examined joint categories of MVPA and weight lifting in relation to cancer risk for significant associations.
Results After adjusting for all covariates including MVPA, we observed a statistically significant lower risk of colon cancer (Ptrend = 0.003) in individuals who weight lifted; the HR and 95% CI associated with low and high weight lifting as compared with no weight lifting were 0.75 (95% CI, 0.66–0.87) and 0.78 (95% CI, 0.61–0.98), respectively. The weight lifting-colon cancer relationship differed between men and women (any weight lifting vs no weight lifting: HRmen = 0.91; 95% CI, 0.84–0.98; HRwomen = 1.00; 95% CI, 0.93–1.08; Pinteraction = 0.008). A lower risk of kidney cancer among weight lifters was observed but became nonsignificant after adjusting for MVPA (Ptrend = 0.06), resulting in an HR of 0.94 (95% CI, 0.78–1.12) for low weight lifting and 0.80 (95% CI, 0.59–1.11) for high weight lifting.
Conclusions Participants who engaged in weight lifting had a significantly lower risk of colon cancer and a trend toward a lower risk of kidney cancer than participants who did not weight lift.

Trends in Step-determined Physical Activity among Japanese Adults from 1995 to 2016

01-09-2019 – TAKAMIYA, TOMOKO; INOUE, SHIGERU

Journal Article

Purpose We tried to clarify the trends in step-determined physical activity (PA) among Japanese adults from 1995 to 2016.
Methods Raw data from the National Health and Nutrition Surveys Japan (NHNS-J) performed between 1995 and 2016 were used, in compliance with the Statistics Act of Japan. NHNS-J was conducted annually by the Japanese government (the Ministry of Health, Labour, and Welfare) using a representative Japanese sample, with the same sampling method every year except in 2012 and 2016. A 1-d pedometer survey was conducted each year as a part of the NHNS-J, on a weekday in November specified by each individual. Because of the difference in age distribution of the samples, age-adjusted mean steps per day were calculated from 1995 to 2016 by sex. The time trends of step-determined PA levels among Japanese adults were described and examined using Joinpoint regression.
Results The highest age-adjusted mean number of steps for men was 8235 steps per day in 2000, whereas it was 7667 steps per day in 2015. The highest age-adjusted mean numbers of steps for women were 7474 steps per day in 1998 and 6691 steps per day in 2015. The age-adjusted step-determined PA trend showed significantly decreasing trend from 1997 to 2008 in men (annual percentage change, −0.74; P < 0.001) and from 1998 to 2008 (annual percentage change, −1.30; P < 0.001) in women, by Joinpoint regression.
Conclusion The age-adjusted step-determined PA among Japanese adults between 1995 and 2016 decreased from around 1997 to 1998 until around 2008, but since then, the decreasing trend became unclear both in men and in women. Continuous monitoring of PA trends is essential to assess the effectiveness of policies.

Obesity Prevalence and Musculoskeletal Injury History in Probation Officers

01-09-2019 – MOTA, JACOB A.; KERR, ZACHARY Y.; GERSTNER, GENA R.; GIULIANI, HAYDEN K.; RYAN, ERIC D.

Journal Article

Purpose The purpose of the present investigation was to identify 1) the prevalence of overweight and obesity and 2) factors associated with previous work-related musculoskeletal injury, and physical activity (PA) levels in North Carolina probation officers.
Methods North Carolina probation officers (N = 1866) were sent a questionnaire on demographics, work history, injury history, and PA. A multivariable logistic regression model estimated the odds of reporting work-related musculoskeletal injury history within the past year, and multivariable ordinal logistic regression estimated the odds of reporting lower PA levels in the previous month. Odds ratios (OR) with 95% confidence intervals (CI) excluding 1.00 were deemed significant.
Results Complete data were available for 1323 probation officers (70.9% completion rate; 46.5% female; mean ± SD age, 39.9 ± 10.0 yr). Officers that were classified as overweight and obese were 80.8% (body mass index BMI ≥ 25 kg·m−2), with 49.9% and 9.5% categorized as obese (BMI ≥ 30 kg·m−2) and severely obese (BMI ≥ 40 kg·m−2), respectively. Being older (1-yr increase; OR, 1.06; 95% CI, 1.04–1.09) and severely obese (compared to normally weighted; OR, 2.56; 95% CI, 1.19–5.51) was associated with a greater odds of sustaining a work-related musculoskeletal injury in the past year. A higher number of years of employment (1-yr increase; OR, 1.03; 95% CI, 1.01–1.04), being overweight or obese (compared to normal weight; OR, 1.57–3.22) and being female (compared with male: OR, 0.38; 95% CI, 0.31–0.47) was associated with the greater odds of lower PA levels in the previous month.
Conclusions The prevalence of obesity is alarmingly high in probation officers, and is associated with a greater likelihood of sustaining previous work-related musculoskeletal injury and engaging in lower amounts of PA. Public safety administrators may consider worksite exercise/diet interventions and annual physical employment standards to combat obesity.

Resistance Training Induces Antiatherogenic Effects on Metabolomic Pathways

01-09-2019 – SARIN, HEIKKI V.; AHTIAINEN, JUHA P.; HULMI, JUHA J.; IHALAINEN, JOHANNA K.; WALKER, SIMON; KÜÜSMAA-SCHILDT, MARIA; PEROLA, MARKUS; PELTONEN, HEIKKI

Journal Article

Introduction Arising evidence suggests that resistance training has the potential to induce beneficial modulation of biomarker profile. To date, however, only immediate responses to resistance training have been investigated using high-throughput metabolomics whereas the effects of chronic resistance training on biomarker profile have not been studied in detail.
Methods A total of 86 recreationally active healthy men without previous systematic resistance training background were allocated into (i) a resistance training (RT) group (n = 68; age, 33 ± 7 yr; body mass index, 28 ± 3 kg·m−2) and (ii) a non-RT group (n = 18; age, 31 ± 4 yr; body mass index, 27 ± 3 kg·m−2). Blood samples were collected at baseline (PRE), after 4 wk (POST-4wk), and after 16 wk of resistance training intervention (POST-16wk), as well as baseline and after the non-RT period (20–24 wk). Nuclear magnetic resonance–metabolome platform was used to determine metabolomic responses to chronic resistance training.
Results Overall, the resistance training intervention resulted in favorable alterations (P < 0.05) in body composition with increased levels of lean mass (~2.8%), decreased levels of android (~9.6%), and total fat mass (~7.5%). These changes in body composition were accompanied by antiatherogenic alterations in serum metabolome profile (false discovery rate < 0.05) as reductions in non–high-density lipoprotein cholesterol (e.g., free cholesterol, remnant cholesterol, intermediate-density lipoprotein cholesterols, low-density lipoprotein cholesterols) and related apolipoprotein B, and increments in conjugated linoleic fatty acids levels were observed. Individuals with the poorest baseline status (i.e., body composition, metabolome profile) benefitted the most from the resistance training intervention.
Conclusions In conclusion, resistance training improves cardiometabolic risk factors and serum metabolome even in previously healthy young men. Thus, suggesting attenuated risk for future cardiovascular disease.

Effectiveness of Aerobic Exercise Programs for Health Promotion in Metabolic Syndrome

01-09-2019 – MORALES-PALOMO, FELIX; RAMIREZ-JIMENEZ, MIGUEL; ORTEGA, JUAN FERNANDO; MORA-RODRIGUEZ, RICARDO

Purpose Continuous and interval are the two types of aerobic exercise training commonly used for health promotion. We sought to determine which aerobic exercise training program results in larger health improvements in metabolic syndrome (Met
S) individuals.
Methods One hundred twenty-one Met
S patients (age, 57 ± 8 yr; weight, 92 ± 15 kg; and Met
S factors, 3.8 ± 0.8 components) with low initial cardiorespiratory fitness (CRF) (V˙O2peak, 24.0 ± 5.5 m
L·kg−1·min−1) were randomized to undergo one of the following 16-wk exercise program: (a) 4 × 4-min high-intensity interval training at 90% of HRMAX (4HIIT group; n = 32), (b) 50-min moderate-intensity continuous training at 70% of HRMAX (MICT group; n = 35), (c) 10 × 1-min HIIT at 100% of HRMAX (1HIIT group; n = 32), or (d) no exercise control group (CONT; n = 22). We measured the evolution of all five Met
S components (i.e., Met
S Z Score) and CRF (assessed by V˙O2peak) before and after intervention.
Results Met
S Z score decreased 41% after 4HIIT (95% confidence interval CI, 0.25–0.06; P < 0.01) and 52% in MICT (95% CI, 0.24–0.06; P < 0.01), whereas it did not change in 1HIIT (decreased 24%; 95% CI, −0.16 to 0.03; P = 0.21) and CONT (increased 20%; 95% CI, −0.19 to 0.04; P = 0.22). However, the three exercise groups improved similarly their V˙O2peak (4HIIT, 11%; 95% CI, 0.14–0.33; MICT, 12%; 95% CI, 0.18–0.36; and 1HIIT, 14%; 95% CI, 0.21–0.40 L·min−1; all P < 0.001).
Conclusions Our findings suggest that in sedentary individuals with Met
S and low initial CRF level any aerobic training program of 16 wk with a frequency of three times per week is sufficient stimulus to raise CRF. However, the more intense but shorter 1HIIT training program is not effective on improving Met
S Z score, and thus we caution its recommendation for health promotion purposes in this population.

Match Play–induced Changes in Landing Biomechanics with Special Focus on Fatigability

01-09-2019 – SMEETS, ANNEMIE; VANRENTERGHEM, JOS; STAES, FILIP; VERSCHUEREN, SABINE

Journal Article

Introduction Growing evidence exists that match-related fatigue induces biomechanical alterations that might increase lower extremity injury risk. Fatigue studies often use match simulation protocols that expose all subjects to a standardized demand (e.g., a fixed distance/time). In those studies, the induced level of fatigue depends then on subjects’ fatigability. If between-subject variability in fatigability is high, this might confound overall fatigue effects. Therefore, the first aim was to investigate whether a fatigue protocol with fixed demand causes alterations in landing patterns. Second, we assessed the relationship between fatigability and landing patterns as we hypothesized that athletes with high fatigability would show movement patterns that involve greater injury risk.
Methods Eighteen athletes performed three different unilateral landing tasks before and after a match simulation protocol while muscle activation (vastus medialis, vastus lateralis, hamstrings medialis, hamstrings lateralis, gastrocnemius medialis, gastrocnemius lateralis, and gluteus medius) and landing kinematics and kinetics of the hip, knee, and ankle joint were recorded. Furthermore, RPE was administered to measure fatigability. ANOVA analyses were conducted to investigate fatigue effects on landing patterns. Correlation analyses assessed the relationship between fatigability (postfatigue RPE) and landing patterns.
Results The ANOVA analyses did not show any overall postfatigue alterations in landing patterns. However, correlation analyses showed an association between fatigability and landing patterns. Athletes who had higher RPE scores showed smaller postfatigue knee flexion angles and smaller pre- and postfatigue knee abduction angles across different landing tasks.
Conclusion The fixed demand protocol did not cause overall alterations in landing patterns. When fatigability was taken into account, high fatigability was related with less optimal landing patterns.

Effect of Shoe and Surface Stiffness on Lower Limb Tendon Strain in Jumping

01-09-2019 – FIRMINGER, COLIN R.; BRUCE, OLIVIA L.; WANNOP, JOHN W.; STEFANYSHYN, DARREN J.; EDWARDS, W. BRENT

Journal Article

Background Tendinopathies are painful overuse injuries observed in athletes participating in jumping sports. These injuries are heavily dependent on the resulting strain from the applied mechanical load. Therefore, mechanisms to reduce tendon strain may represent a primary prevention strategy to reduce the incidence of tendinopathy.
Purpose The purpose of this study was to examine the effect of shoe and surface stiffness on Achilles and patellar tendon strains during jumping. We hypothesized that less stiff shoes and surfaces would reduce Achilles and patellar tendon strains during jumping.
Methods Thirty healthy male basketball players performed countermovement jumps in three shoes and on three surfaces with different stiffness properties while motion capture, force platform, and jump height data were collected. Magnetic resonance imaging was used to obtain participant-specific tendon morphology, and a combined dynamometry/ultrasound/electromyography session was used to obtain tendon material properties. Finally, a musculoskeletal model was used to estimate tendon strains in each surface and shoe combination.
Results Achilles tendon strains during landing were reduced by 5.3% in the least stiff shoe compared with the stiffest shoe (P = 0.021) likely due to in bending stiffness altering the center of pressure location. Furthermore, Achilles tendon strains during landing were 5.7% and 8.1% lower on the stiffest surface compared with the least stiff and middle stiffness surfaces, respectively (P ≤ 0.047), because of changes in ground reaction force magnitude and center of pressure location. No effects of shoe stiffness or surface construction were observed for jump height (P > 0.243) or peak patellar tendon strains (P > 0.259).
Conclusions Changes to shoe stiffness and surface construction can alter Achilles tendon strains without affecting jump performance in athletes.

Transfer Learning Effects of Biofeedback Running Retraining in Untrained Conditions

01-09-2019 – ZHANG, JANET HANWEN; CHAN, ZOE YAU-SHAN; AU, IVAN PUI-HUNG; AN, WINKO WENKANG; SHULL, PETER BRADLEY; CHEUNG, ROY TSZ-HEI

Journal Article

Purpose Running gait retraining via peak tibial shock biofeedback has been previously shown to reduce impact loading and mitigate running-related symptoms. In previous research, peak tibial shock is typically measured and trained for one limb at a single constant training speed during all training sessions. The goal of this study was to determine how runners transfer learning in the trained limb to the untrained limb at different unconstrained speeds.
Methods Thirteen runners (3 females, age = 41.1 ± 6.9 yr, running experience = 6.8 ± 4.4 yr, weekly running distance = 30.7 ± 22.2 km) underwent running gait biofeedback retraining via continuous tibial acceleration measured at the right distal tibia. Before and after the training, participants were asked to run at their self-selected constrained training speeds (2.8 ± 0.2 m·s−1) and at 110% and 90% of the training speed. Pretraining and posttraining peak tibial shock values for each limb were compared.
Results Participants reduced peak tibial shock in the trained limb by 35% to 37% (P < 0.05, Cohen’s d = 0.78–0.85), and in the untrained limb by 20% to 23% (P < 0.05, Cohen’s d = 0.51–0.71) across the three testing speeds. The reduction was not significantly different between the trained and untrained limbs (P = 0.31–0.79, Cohen’s d = 0.18–0.45). Similarly, there was no difference in peak tibial shock reduction among the three running speeds (P = 0.48–0.61, Cohen’s d = 0.06–0.45).
Conclusion Participants demonstrated transfer learning effects evidenced by concomitant reduced peak tibial shock in the untrained limb, and the learning effects were retrained when running at a 10% variance of the training speed.

Serum Endocannabinoid and Mood Changes after Exercise in Major Depressive Disorder

01-09-2019 – MEYER, JACOB D.; CROMBIE, KEVIN M.; COOK, DANE B.; HILLARD, CECILIA J.; KOLTYN, KELLI F.

Journal Article

The endocannabinoid (e
CB) system is implicated in the pathophysiology of depression and is responsive to acute exercise in healthy adults.
Purpose We aimed to describe acute changes in serum e
CB across a prescribed moderate (MOD) and a self-selected/preferred (PREF) intensity exercise session in women with major depressive disorder (MDD) and determine relationships between changes in e
CB and mood states.
Methods Women with MDD (n = 17) exercised in separate sessions for 20 min on a cycle ergometer at both MOD or PREF in a within-subjects design. Blood was drawn before and within 10 min after exercise. Serum concentrations of e
CB (anandamide AEA, 2-arachidonoylglycerol) and related lipids (palmitoylethanolamine, oleoylethanolamine, 2-oleoylglycerol) were quantified using stable isotope-dilution, liquid chromatography/mass spectrometry/mass spectrometry. The profile of mood states and state-trait anxiety inventory (state only) were completed before, 10 min and 30 min postexercise.
Results Significant elevations in AEA (P = 0.013) and oleoylethanolamine (P = 0.024) occurred for MOD (moderate effect sizes: Cohen’s d = 0.58 and 0.41, respectively). Significant (P < 0.05) moderate negative associations existed between changes in AEA and mood states for MOD at 10 min (depression, confusion, fatigue, total mood disturbance TMD and state anxiety) and 30 min postexercise (confusion, TMD and state anxiety). Significant (P < 0.05) moderate negative associations existed between 2-arachidonoylglycerol and mood states at 10 min (depression and confusion) and 30 min postexercise (confusion and TMD). Changes in e
CB or related lipids or e
CB–mood relationships were not found for PREF.
Conclusion Given the broad, moderate–strength relationships between improvements in mood states and e
CB increases after MOD, it is plausible that the e
CB system contributes to the mood-enhancing effects of prescribed acute exercise in MDD. Alternative mechanisms are likely involved in the positive mood state effects of preferred exercise.

Overactivation of the Reward System and Deficient Inhibition in Exercise Addiction

01-09-2019 – HUANG, QIN; HUANG, JIAAI; CHEN, YANXIA; LIN, DENG; XU, SHUN; WEI, JINGPING; QI, CHANGZHU; XU, XIA

Journal Article

Purpose Behavior studies have found that exercise addiction is associated with high impulsivity. In other addictions, neural mechanisms of impulsivity reflect abnormalities in the reward and inhibition systems. In this study, we determined whether abnormalities existed in the reward and inhibition systems of exercise addicts.
Methods Three groups of male participants (15 exercise addicts, 18 regular exercisers, and 16 exercise avoiders) completed the Mini International Personality Item Pool (Mini-IPIP), the classic go/no-go task, and the exercise-related go/no-go task. Event-related potentials (ERP) were recorded during the go/no-go tasks, and correctly performed trials were analyzed.
Results Exercise addicts scored lower for extraversion and higher for neuroticism, reflecting a poor capacity for emotional regulation and impulse control, and had larger N2 and P3d amplitudes during the exercise-related go/no-go task. Exercise addicts and exercise avoiders demonstrated impaired accuracy in the exercise-related go/no-go task and had larger N2 amplitudes compared with regular exercisers during the letter–digit go/no-go task. Exercise addicts and regular exercisers showed larger Go-N1 and Go-P2 amplitudes compared with exercise avoiders during the exercise-related go/no-go task. Exercisers (exercise addicts and regular exercisers) demonstrated higher activation in response to exercise-related stimuli as reflected by larger N1 and P2, and addicts (exercise addicts) demonstrated poorer inhibition as reflected by larger N2 and P3d amplitudes. Go-N1 and Go-P2 were significantly correlated with no-go accuracy in exercise-related task.
Conclusions Exercise addicts scored higher for the neuroticism personality trait and exhibited overactivation of the reward system and underactivation of the inhibition system. Overactivation of the reward system may be related to long-term exposure to exercise. Underactivation of the inhibition system may be a crucial factor in exercise addiction.

Beep Test Performance Is Influenced by 30 Minutes of Cognitive Work

01-09-2019 – MACMAHON, CLARE; HAWKINS, ZACKARY; SCHÜCKER, LINDA

Journal Article

Purpose This study explored conflicting findings in the literature on the influence of perceived cognitive fatigue on physical performance by testing the effect of the Stroop task (high cognitive load) on an intermittent running test (beep test).
Methods In a within-subjects repeated-measures experiment, 13 active athletes performed the beep test on two occasions, in a randomized, counterbalanced order. In each session, a preceding cognitive task was completed for 30 min, with the incongruent Stroop task in the high load condition, and the congruent Stroop task in the low load condition. Perceived cognitive fatigue was measured before testing (baseline) and at 10, 20, and 30 min of the cognitive load manipulation. Perceived effort on the cognitive task and general motivation for the physical task (beep test) were measured before the beep test, and motivation-related perception of the beep test and ratings of perceived exertion were measured after completion of the test. Heart rate and beep test performance (completion stage and time) were also recorded.
Results The incongruent Stroop task was perceived as more fatiguing and effortful. Participants also withdrew from the beep test significantly earlier in the high load condition (M = 8:48 min, SD = 2:32 min) compared to the low load condition (M = 9:20 min, SD = 2:28 min), F (1,11) = 21.76, P < 0.01, ŋ2 = 0.67. There were no differences in heart rate or general motivation between the two conditions.
Conclusions Whereas previous research shows that active athletes can maintain performance on the beep test after 10 min of the incongruent Stroop task, this study shows that performance is impaired after 30 min. Variables in need of exploration in future investigations include experience with both the physical and cognitive task.

Microparticle Responses to Aerobic Exercise and Meal Consumption in Healthy Men

01-09-2019 – HIGHTON, PATRICK J.; GOLTZ, FERNANDA R.; MARTIN, NAOMI; STENSEL, DAVID J.; THACKRAY, ALICE E.; BISHOP, NICOLETTE C.

Journal Article

Purpose Microparticles (MP) are shed extracellular vesicles that express the prothrombotic tissue factor (TF). Aerobic exercise may reduce MP count and TF expression. This study investigated the impact of acute running or rest followed by standardized meal consumption on MP phenotypes and TF expression.
Methods Fifteen males (age, 22.9 ± 3.3 yr; body mass, 81.9 ± 11.4 kg; V˙O2max, 54.9 ± 6.5 m
L·kg−1·min−1; mean ± SD) completed 1 h of running (70% V˙O2max) or rest at 9:00 AM and consumed a standardized meal (1170 kcal, 43% CHO, 17% PRO, 40% fat) at 10:45 AM. Venous blood samples were taken at 9:00 AM, 10:00 AM, and 11:30 AM. The MP concentration, diameter, phenotypes, and TF expression were assessed using nanoparticle tracking analysis and flow cytometry.
Results Nanoparticle tracking analysis identified no changes in MP concentration or diameter in response to time or trial. Flow cytometry revealed total MP count increased from 9:00 AM to 10:00 AM (1.62 ± 2.28 to 1.74 ± 2.61 × 1010 L−1, P = 0.016, effect size (η2) = 0.105), but was unaffected by trial. TF+ platelet-derived MP % reduced from 9:00 AM to 10:00 AM (44.0% ± 21.2% to 21.5% ± 9.3%, P = 0.001, η2 = 0.582) after exercise only (control, 36.8% ± 18.2% to 34.9% ± 11.9%; P = 0.972). TF+ neutrophil-derived MP percentage reduced from 9:00 AM to 11:30 AM (42.3% ± 17.2% to 25.1% ± 14.9%; P = 0.048, η2 = 0.801) in the exercise trial only (control, 28.5% ± 15.7% to 32.2% ± 9.6%; P = 0.508).
Conclusions Running induced a significant reduction in %TF+ platelet and neutrophil MP, suggesting a transient reduction in cardiovascular risk via reduced TF-stimulated thrombosis. This requires further investigation over longer periods in cardiovascular disease populations.

Impact of Eccentric or Concentric Training on Body Composition and Energy Expenditure

01-09-2019 – TOURON, JULIANNE; PERRAULT, HÉLÈNE; JULIAN, VALÉRIE; MAISONNAVE, LAURA; DEAT, PHILIPPE; AUCLAIR-RONZAUD, JULIETTE; SALLES, JÉRÔME; WALRAND, STÉPHANE; HERMET, JULIEN; RIGAUDIERE, JEAN-PAUL; LEBECQUE, PATRICE; MALPUECH-BRUGERE, CORINNE; MONTAURIER, CHRISTOPHE; PEREIRA, BRUNO; COXAM, VÉRONIQUE; COSTES, FRÉDÉRIC; RICHARD, RUDDY

Journal Article

Purpose To compare the effects of 8-wk eccentric (ECC) versus concentric (CON) training using downhill and uphill running in rats on whole body composition, bone mineral density (BMD), and energy expenditure.
Methods Animals were randomly assigned to one of the following groups: 1) control (CTRL), 2) +15% uphill-running slope (CON), 3) −15% downhill-running slope (ECC15), and 4) −30% downhill-running slope (ECC30). Those programs enabled to achieve conditions of isopower output for CON and ECC15 and of iso-oxygen uptake (V˙O2) for CON and ECC30. Trained rats ran 45 min at 15 m·min−1 five times per week. Total body mass, fat body mass, and lean body mass (LBM) measured through Echo
MRI™, and 24-h energy expenditure including basal metabolic rate (BMR) assessed using Pheno
Master/Lab
Master™ cage system were obtained before and after training. At sacrifice, the right femur was collected for bone parameters analysis.
Results Although total body mass increased in all groups over the 8-wk period, almost no change occurred for fat body mass in exercised groups (CON, −4.8 ± 6.18 g; ECC15, 0.6 ± 3.32 g; ECC30, 2.6 ± 6.01 g). The gain in LBM was mainly seen for ECC15 (88.9 ± 6.85 g) and ECC30 (101.6 ± 11.07 g). ECC was also seen to positively affect BMD. An increase in BMR from baseline was seen in exercise groups (CON, 13.9 ± 4.13 k
J·d−1; ECC15, 11.6 ± 5.10 k
J·d−1; ECC30, 18.3 ± 4.33 k
J·d−1) but not in CTRL one. This difference disappeared when BMR was normalized for LBM.
Conclusions Results indicate that for iso-V˙O2 training, the impact on LBM and BMD is enhanced with ECC as compared with CON, and that for isopower but lower V˙O2 ECC, an important stimulus for adaptation is still observed. This provides further insights for the use of ECC in populations with cardiorespiratory exercise limitations.

Estimating Energy Expenditure during Level, Uphill, and Downhill Walking

01-09-2019 – LOONEY, DAVID P.; SANTEE, WILLIAM R.; HANSEN, ERIC O.; BONVENTRE, PETER J.; CHALMERS, CHRISTOPHER R.; POTTER, ADAM W.

Journal Article

Introduction The load carriage decision aid (LCDA) walking equation was developed from literature-aggregated group mean data to calculate standing and level walking energy expenditures in healthy, military-age adults. The LCDA walking equation has not been validated for use in individuals or graded walking.
Purpose We aimed to validate the LCDA walking equation as a predictor of standing and level walking energy expenditure in individuals and expand to a new graded walking equation for uphill and downhill walking.
Methods We compiled standing, level walking, and graded walking energy expenditures measured in 95 participants from 11 studies. Walking speeds reached up to 1.96 m·s−1 with grades ranging between −40% and 45%. The LCDA walking equation was validated against the aggregated standing and level walking data. The new LCDA graded walking equation was developed and cross-validated on the graded walking trials. We compared each equation against four reference predictive equations with the standard error of estimation (SEE) as the primary criterion.
Results The LCDA walking equation accurately estimated standing and level walking energy expenditure (bias, −0.02 ± 0.20 W·kg−1; SEE, 0.20 W·kg−1). Addition of the novel grade term resulted in precise estimates of uphill and downhill walking energy expenditure (bias, 0.09 ± 0.40 W·kg−1; SEE, 0.42 W·kg−1).
Conclusions The LCDA walking equation is a valid predictor of standing and walking energy expenditure in healthy, military-age individuals. We developed a novel grade term for estimating both uphill and downhill walking energy expenditure with a single equation. Practitioners can use the new LCDA graded walking equation to calculate energy expenditure during standing as well as walking on level, uphill, and downhill slopes.

Effect of Muscle–Tendon Unit Length on Child–Adult Difference in Neuromuscular Fatigue

01-09-2019 – PIPONNIER, ENZO; MARTIN, VINCENT; CHALCHAT, EMERIC; BONTEMPS, BASTIEN; JULIAN, VALÉRIE; BOCOCK, OLIVIA; DUCLOS, MARTINE; RATEL, SÉBASTIEN

Purpose The purpose of this study was to compare the development and etiology of neuromuscular fatigue of the knee extensor muscles at different muscle–tendon unit (MTU) lengths during repeated maximal voluntary isometric contractions (MVIC) between boys and men.
Methods Twenty-two prepubertal boys (9–11 yr) and 22 men (18–30 yr) performed three knee extensor fatigue protocols at short (SHORT), optimal (OPT), and long (LONG) MTU lengths, consisting of repeating 5-s MVIC interspersed with 5-s passive recovery periods until torque reached 60% of the initial MVIC torque. The etiology of neuromuscular fatigue was identified using noninvasive methods such as surface electromyography, near-infrared spectroscopy, magnetic nerve stimulation and twitch interpolation technique.
Results The number of repetitions was significantly lower in men at OPT (14.8 ± 3.2) and LONG (15.8 ± 5.8) than boys (39.7 ± 18.4 and 29.5 ± 10.2, respectively; P < 0.001), whereas no difference was found at SHORT between both age groups (boys, 33.7 ± 15.4; men, 40.9 ± 14.2). At OPT and LONG boys showed a lower reduction in the single potentiated twitch (Qtwpot) and a greater decrease in the voluntary activation level than men. At SHORT, both populations displayed a moderate Qtwpot decrement and a significant voluntary activation reduction (P < 0.001). The differences in maximal torque between boys and men were almost twice greater at OPT (223.9 N·m) than at SHORT (123.3 N·m) and LONG (136.5 N·m).
Conclusions The differences in neuromuscular fatigue between children and adults are dependent on MTU length. Differences in maximal torque could underpin differences in neuromuscular fatigue between children and adults at OPT and SHORT. However, at LONG these differences do not seem to be explained by differences in maximal torque. The origins of this specific effect of MTU length remain to be determined.

Statistical Power in a Recent Study by Schoenfeld et al.

01-09-2019 – Mizelman, Eliran

No abstract available

Response

01-09-2019 – Schoenfeld, Brad J.; Contreras, Bret; Krieger, James; Grgic, Jozo; Delcastillo, Kenneth; Belliard, Ramon; Alto, Andrew

No abstract available

Potential Confounding Effects of Intensity on Training Response

01-09-2019 – Boullosa, Daniel; Esteve-Lanao, Jonathan; Seiler, Stephen

No abstract available

Response

01-09-2019 – Zinner, Christoph; Schäfer Olstad, Daniela; Sperlich, Billy

No abstract available

Advances in Sport and Exercise Psychology, 4th Edition

01-09-2019 –

No abstract available

Cardiology: An Integrated Approach

01-09-2019 –

No abstract available