Purpose: To quantify the acute effects of a spectrum of eccentric load reductions on neuromechanical adjustments during the performance of weighted jump squats (WJSs). Methods: On separate days, 16 well-trained participants performed WJS trials with various eccentric load reductions (0% [body mass only], 25%, 50%, 75%, and 100% [standard WJS] of concentric load) with a mechanical braking unit, while concentric load was set at 30% of peak isometric squat force in all trials. A force platform and a motion-capture system were used to assess neuromuscular performance. Results: Peak power output was 6.2% (4.7%) higher when load was reduced by 50% versus 0% (55.4 [7.8] vs 51.9 [7.6] W/kg; P = .001). Compared with no braking (0.326 [0.059] m), jump height was ∼13% to 17% higher for all eccentric load reduction conditions (all P < .001). Vertical ground reaction forces were progressively lower for 25%, 50%, 75%, and 100% loading conditions (–22.1% [14.6%], –32.3% [10.8%], –42.0% [13.2%], and –46.1% [14.7%]; all P ≤ .001) in reference to body mass only. Conclusion: Eccentric load reduction is advantageous compared with traditional isoinertial loading for improving both jump height and peak power output during the concentric portion of maximal-effort WJS. This practice also decreases mechanical constraints in the lower extremities, which may become beneficial for load-compromised individuals.
Qian Zhang, Liang Zhang, Bing Yan, and Olivier Girard
Sarah de Jager, Stefaan Van Damme, Siegrid De Baere, Siska Croubels, Ralf Jäger, Martin Purpura, Eline Lievens, Jan G. Bourgois, and Wim Derave
Carnosine (β-alanyl-L-histidine) and its methylated analogues anserine and balenine are highly concentrated endogenous dipeptides in mammalian skeletal muscle that are implicated in exercise performance. Balenine has a much better bioavailability and stability in human circulation upon acute ingestion, compared to carnosine and anserine. Therefore, ergogenic effects observed with acute carnosine and anserine supplementation may be even more pronounced with balenine. This study investigated whether acute balenine supplementation improves physical performance in four maximal and submaximal exercise modalities. A total of 20 healthy, active volunteers (14 males; six females) performed cycling sprints, maximal isometric contractions, a 4-km TT and 20-km TT following either preexercise placebo or 10 mg/kg of balenine ingestion. Physical, as well as mental performance, along with acid–base balance and glucose concentration were assessed. Balenine was unable to augment peak power (p = .3553), peak torque (p = .3169), time to complete the 4 km (p = .8566), nor 20 km time trial (p = .2660). None of the performances were correlated with plasma balenine or CN1 enzyme activity. In addition, no effect on pH, bicarbonate, and lactate was observed. Also, the supplement did not affect mental performance. In contrast, glucose remained higher during and after the 20 km time trial following balenine ingestion. In conclusion, these results overall indicate that the functionality of balenine does not fully resemble that of carnosine and anserine, since it was unable to elicit performance improvements with similar and even higher plasma concentrations.
Zachary L. Mannes, Erin G. Ferguson, Nicole Ennis, Deborah S. Hasin, and Linda B. Cottler
Over 80% of National Football League (NFL) retirees experience daily pain. Pain acceptance is an important psychological construct implicated in the intensity of chronic pain, though these findings have not been extended to NFL retirees. Therefore, the current study examined the association between pain acceptance and pain intensity among former NFL athletes. NFL retirees (N = 90) recruited from 2018 to 2019 completed questionnaires that assessed pain, substance use, and NFL career information. Multiple linear regression examined the association between current pain acceptance and pain intensity while adjusting for other risk factors of pain. NFL retirees reported average scores of 33.31 (SD = 10.00), and 2.18 (SD = 2.40) on measures of pain acceptance and pain intensity, respectively. After covariate adjustment, greater pain acceptance (β = −0.538, p < .001) was associated with lower pain intensity. These findings can further inform the behavioral and mental health care of retired NFL athletes.
Eleftherios Paraskevopoulos, Georgios Gioftsos, Georgios Georgoudis, and Maria Papandreou
Adherence to exercise rehabilitation has been shown to be an important factor that may influence successful treatment. In professional athletes, a significant reduction in exercise adherence delays recovery. The aim of this study was to explore barriers to and facilitators of exercise rehabilitation adherence in injured volleyball athletes. Eight professional volleyball athletes were recruited, and qualitative data were collected using semistructured interviews. All athletes had completed their rehabilitation program after they had suffered a musculoskeletal injury. All data were analyzed using thematic analysis after the investigators ensured that saturation had been reached. Pain was identified as a significant barrier to exercise adherence by all athletes. The provision of social support, including mental, practical, and task related, also had a significant positive impact. The athletes’ ability to develop the necessary coping strategies and confidence on performing exercises at home was also mentioned as a factor that affected exercise adherence, although less often.
Dean R. Watson, Andrew P. Hill, and Daniel J. Madigan
Attitudes toward help-seeking will contribute to whether athletes ask for support for performance and mental health issues when needed. While research outside of sport has found perfectionism is related to negative attitudes toward help-seeking, no studies have examined the relationship in sport. The authors provided the first test of whether perfectionism predicted attitudes toward both sport psychology support and mental health support. One hundred and sixty-six collegiate athletes completed measures of perfectionism and attitudes toward sport psychology support and mental health support. Multiple regression analyses revealed that perfectionistic concerns positively predicted closedness and stigma toward sport psychology support and mental health support, and negatively predicted help-seeking toward mental health support. However, perfectionistic strivings negatively predicted stigma toward sport psychology support and mental health support, and positively predicted confidence in sport psychology support and help-seeking toward mental health support. Athletes higher in perfectionistic concerns are less likely to seek support when required.
Janet Hauck and Isabella Felzer-Kim
Background: This study investigated the effect of an adapted physical activity (APA) course on knowledge and perceptions of preservice trainees regarding physical activity (PA) and autism spectrum disorder in 3 areas: knowledge/perspectives, importance and ease of improving developmental domains, and importance and ease of improving motor skills. Methods: Four hundred upper-level undergraduate students were recruited to participate in this survey-based study (251 APA students and 149 non-APA students participated). Survey data were analyzed using multivariate analyses of variance. Results: Participants estimated that the moderate to vigorous PA recommendations are 39.34 minutes per day, that 46.65% of moderate to vigorous PA occurs during school, and that 61.03% of children have motor difficulties. Participants perceived activities of daily living, sleep habits, and heart health as the easiest domains to improve, and problem behaviors, social skills, and self-esteem as the most difficult domains to improve. Knowledge/perspectives regarding autism spectrum disorder and PA were different by APA exposure (F 12,324 = 3.11, P < .001). Differences included self-efficacy in providing PA advice, knowledge of PA guidelines, and willingness to provide motor assessment referrals. Students differed by APA exposure in the importance of developmental domains (F 8,381 = 4.37, P < .001) but not ease of improving those domains. Conclusion: Results suggest that APA education and contact with children with disabilities improves self-efficacy, perspectives, and knowledge of PA and motor concerns in children with autism spectrum disorder.
Harry Pope, Max Davis, M. Begona Delgado-Charro, Oliver J. Peacock, Javier Gonzalez, and James A. Betts
Phosphate is integral to numerous metabolic processes, several of which strongly predict exercise performance (i.e., cardiac function, oxygen transport, and oxidative metabolism). Evidence regarding phosphate loading is limited and equivocal, at least partly because studies have examined sodium phosphate supplements of varied molar mass (e.g., mono/di/tribasic, dodecahydrate), thus delivering highly variable absolute quantities of phosphate. Within a randomized cross-over design and in a single-blind manner, 16 well-trained cyclists (age 38 ± 16 years, mass 74.3 ± 10.8 kg, training 340 ± 171 min/week; mean ± SD) ingested either 3.5 g/day of dibasic sodium phosphate (Na2HPO4: 24.7 mmol/day phosphate; 49.4 mmol/day sodium) or a sodium chloride placebo (NaCl: 49.4 mmol/day sodium and chloride) for 4 days prior to each of two 30-km time trials, separated by a washout interval of 14 days. There was no evidence of any ergogenic benefit associated with phosphate loading. Time to complete the 30-km time trial did not differ following ingestion of sodium phosphate and sodium chloride (3,059 ± 531 s vs. 2,995 ± 467 s). Accordingly, neither absolute mean power output (221 ± 48 W vs. 226 ± 48 W) nor relative mean power output (3.02 ± 0.78 W/kg vs. 3.08 ± 0.71 W/kg) differed meaningfully between the respective intervention and placebo conditions. Measures of cardiovascular strain and ratings of perceived exertion were very closely matched between treatments (i.e., average heart rate 161 ± 11 beats per minute vs. 159 ± 12 beats per minute; Δ2 beats per minute; and ratings of perceived exertion 18 [14–20] units vs. 17 [14–20] units). In conclusion, supplementing with relatively high absolute doses of phosphate (i.e., >10 mmol daily for 4 days) exerted no ergogenic effects on trained cyclists completing 30-km time trials.
Monica Muti, Lisa J. Ware, Lisa K. Micklesfield, Michele Ramsay, Godfred Agongo, Palwende R. Boua, Isaac Kisiangani, Ian Cook, Francesc Xavier Gómez-Olivé, Nigel J. Crowther, Chodziwadziwa Kabudula, Shane A. Norris, and Tinashe Chikowore
Background: This study aimed to explore association of self-reported physical activity domains of work, leisure, and transport-related physical activity and body mass index (BMI) in 9388 adult men and women from the Africa-Wits-INDEPTH partnership for Genomic (AWI-Gen) study in Africa. Africa-Wits-INDEPTH partnership for Genomic is a large, population-based cross-sectional cohort with participants from 6 sites from rural and urban areas in 4 sub-Saharan African countries. Methods: A sex-stratified meta-analysis of cross-sectional data from men and women aged 29–82 years was used to assess the association of physical activity with BMI. Results: Overall, meeting physical activity guidelines of at least 150 minutes per week was associated with 0.82 kg/m2 lower BMI in men (β = −0.80 kg/m2; 95% confidence interval [CI], −1.14 to −0.47) and 0.68 kg/m2 lower BMI in women (β = −0.68 kg/m2; 95% CI, −1.03 to −0.33). Sex and site-specific differences were observed in the associations between physical activity domains and BMI. Among those who met physical activity guidelines, there was an inverse association between transport-related physical activity and BMI in men from Nanoro (Burkina Faso) (β = −0.79 kg/m2; 95% CI, −1.25 to −0.33) as well as work-related physical activity and BMI in Navrongo men (Ghana) (β = −0.76 kg/m2; 95% CI, −1.25 to −0.27) and Nanoro women (β = −0.90 kg/m2; 95% CI, −1.44 to −0.36). Conclusions: Physical activity may be an effective strategy to curb rising obesity in Africa. More studies are needed to assess the impact of sex and geographic location-specific physical activity interventions on obesity.
Martin Buchheit, Maxime Settembre, Karim Hader, and Derek McHugh
Purpose: To examine the association between the programming of days off (ie, no pitch training, days off feet) within turnarounds of varying length and injury rate in elite soccer. Methods: Retrospective data from 56 team seasons of players belonging to 18 elite teams performing in top leagues including the English Premier League, Italian Serie A, Bundesliga, Scottish Premiership, Major League Soccer, and the Dutch Eredivisie from January 2018 to December 2021 were analyzed (total of 1578 players, 2865 injuries, 2859 noninternational matches, and 12,939 training-session days). The turnarounds examined lasted from 3 to 8 days. Only injuries with ≥3-day time loss were retained for analysis. The authors then looked at the injury rate within each microcycle in relation to the presence of a day off or not and its programming sequences in relation to the previous match (ie, day off at D + 1 vs D + 2 for the day after the match or the following, respectively). Results: During 3- and 7-day turnarounds, the sequences including the day off feet at D + 2 were associated with 2 to 3 times lower overall noncontact injury rates than the other programming sequences (Cohen d: 0.9–2.7). For the other turnarounds, the differences between the sequences were unclear. Conclusion: The programming of a day off (or at least “off feet”) at D + 2 may be associated with moderately to largely lower incidence of noncontact injuries, especially during 3- and 7-day turnarounds.
Wei Guo, Andrew Leroux, Haochang Shou, Lihong Cui, Sun Jung Kang, Marie-Pierre Françoise Strippoli, Martin Preisig, Vadim Zipunnikov, and Kathleen Ries Merikangas
The Mobile Motor Activity Research Consortium for Health (mMARCH) is a collaborative network of clinical and community studies that employ common digital mobile protocols and collect common clinical and biological measures across participating studies. At a high level, a key scientific goal which spans mMARCH studies is to develop a better understanding of the interrelationships between physical activity (PA), sleep (SL), and circadian rhythmicity (CR) and mental and physical health in children, adolescents, and adults. mMARCH studies employ wrist-worn accelerometry to obtain objective measures of PA/SL/CR. However, there is currently no consensus on a standard data processing pipeline for raw accelerometry data and few open-source tools which facilitate their development. The R package GGIR is the most prominent open-source software package for processing raw accelerometry data, offering great functionality and substantial user flexibility. However, even with GGIR, processing done in a harmonized and reproducible fashion across multiple analytical centers requires a nontrivial amount of expertise combined with a careful implementation. In addition, there are many statistical methods useful for analyzing PA/SL/CR patterns using accelerometry data which are implemented in non-GGIR R packages, including methods from multivariate statistics, functional data analysis, distributional data analysis, and time series analyses. To address the issues of multisite harmonization and additional feature creation, mMARCH developed a streamlined harmonized and reproducible pipeline for loading and cleaning raw accelerometry data via GGIR, merging GGIR, and non-GGIR features of PA/SL/CR together, implementing several additional data and feature quality checks, and performing multiple analyses including Joint and Individual Variation Explained, an unsupervised machine learning dimension reduction technique that identifies latent factors capturing joint across and individual to each of three domains of PA/SL/CR. The pipeline is easily modified to calculate additional features of interest, and allows for studies not affiliated with mMARCH to apply a pipeline which facilitates direct comparisons of scientific results in published work by mMARCH studies. This manuscript describes the pipeline and illustrates the use of combined GGIR and non-GGIR features by applying Joint and Individual Variation Explained to the accelerometry component of CoLaus|PsyCoLaus, one of mMARCH sites. The pipeline is publicly available via open-source R package mMARCH.AC.