The impact of resistance exercise frequency on muscle protein synthesis rates remains unknown. The aim of this study was to compare daily myofibrillar protein synthesis rates over a 7-day period of low-frequency (LF) versus high-frequency (HF) resistance exercise training. Nine young men (21 ± 2 years) completed a 7-day period of habitual physical activity (BASAL). This was followed by a 7-day exercise period of volume-matched, LF (10 × 10 repetitions at 70% one-repetition maximum, once per week) or HF (2 × 10 repetitions at ∼70% one-repetition maximum, five times per week) resistance exercise training. The participants had one leg randomly allocated to LF and the other to HF. Skeletal muscle biopsies and daily saliva samples were collected to determine myofibrillar protein synthesis rates using 2H2O, with intracellular signaling determined using Western blotting. The myofibrillar protein synthesis rates did not differ between the LF (1.46 ± 0.26%/day) and HF (1.48 ± 0.33%/day) conditions over the 7-day exercise training period (p > .05). There were no significant differences between the LF and HF conditions over the first 2 days (1.45 ± 0.41%/day vs. 1.25 ± 0.46%/day) or last 5 days (1.47 ± 0.30%/day vs. 1.50 ± 0.41%/day) of the exercise training period (p > .05). Daily myofibrillar protein synthesis rates were not different from BASAL at any time point during LF or HF (p > .05). The phosphorylation status and total protein content of selected proteins implicated in skeletal muscle ribosomal biogenesis were not different between conditions (p > .05). Under the conditions of the present study, resistance exercise training frequency did not modulate daily myofibrillar protein synthesis rates in young men.
Brandon J. Shad, Janice L. Thompson, James Mckendry, Andrew M. Holwerda, Yasir S. Elhassan, Leigh Breen, Luc J.C. van Loon, and Gareth A. Wallis
Stephanie G. Kerrigan, Evan M. Forman, Dave Williams, Mitesh Patel, Caitlin Loyka, Fengqing Zhang, Ross D. Crosby, and Meghan L. Butryn
Background: Financial incentives and feedback on behavior offer promise for promoting physical activity. However, evidence for the effect of each of these techniques is inadequate. The present study evaluated the effects of daily versus weekly feedback and incentives contingent on reaching a daily walking goal versus noncontingent incentives in a 2 × 2 trial. Methods: Participants (N = 57) had a body mass index >25 kg/m2 and were insufficiently active. Participants received a daily walking goal that adapted weekly. Results: Participants receiving daily feedback increased daily steps (P = .03) more than those receiving weekly feedback. Participants receiving contingent incentives did not significantly increase steps (P = .12) more than those receiving noncontingent incentives. A trend-level effect (P = .09) suggested that there may be an interaction such that the combination of daily feedback and contingent incentives is most effective. Conclusions: Results indicate that feedback is an important component of remotely delivered PA interventions and that evaluating each component of low-intensity interventions may help to improve efficacy. Moreover, results indicate that possible synergistic effects of feedback and rewards should be investigated further to help optimize interventions.
Kristopher White, Kathryn Wilson, Theresa A. Walton-Fisette, Brian H. Yim, and Michele K. Donnelly
This work built upon previous research examining meritocracy in elite sport by examining the socioeconomic and racial composition of the high schools of 1,881 players on National Football League (NFL) rosters in 2016. The NFL player data from pro-football-reference.com and perceived race data coded from player pictures are matched to school data for 23,785 public high schools in the Common Core of Data and 3,333 private high schools in the Private School Universe Survey. Using t tests of differences in group averages and General Linear Model analysis of variance, the authors found large statistically significant racial disparities within the NFL with Black NFL players attending high schools with an average of twice as many students in poverty and five times as many Black students than the high schools attended by White NFL players. Overall, NFL players attended high schools with lower socioeconomic status student bodies than the general student population, suggesting more meritocracy. However, analysis by player race shows the difference driven by the racial composition of the NFL compared with the general student population, suggesting this meritocracy is more complex; Black NFL players attended higher socioeconomic status schools with more White students than the general Black student population, and White NFL players attended higher socioeconomic status schools with fewer Black students than the general White student population.
Matías Henríquez, Aitor Iturricastillo, Arturo González-Olguín, Felipe Herrera, Sonny Riquelme, and Raul Reina
This study compared physical performance in a group of international cerebral palsy football players during two formats of small-sided games (SSGs) and performance in a simulated game (SG) according to players’ sport classes (FT1, FT2, and FT3). Internal load (heart rate and rating of perceived exertion) and external load (total distance, distance covered at different velocities, maximum speed reached, acceleration, and deceleration) were obtained with global positioning system devices during two formats of SSGs (2-a-side/SSG2 and 4-a-side/SSG4) and an SG (7-a-side). SSG2 demands faster actions compared with SSG4/SG, and significant differences and large effect sizes were found in the distance covered in Speed Zones 5 (16.0−17.9 km/hr) and 6 (>18.0 km/hr; p < .05;
John Bellettiere, Fatima Tuz-Zahra, Jordan A. Carlson, Nicola D. Ridgers, Sandy Liles, Mikael Anne Greenwood-Hickman, Rod L. Walker, Andrea Z. LaCroix, Marta M. Jankowska, Dori E. Rosenberg, and Loki Natarajan
Little is known about how sedentary behavior (SB) metrics derived from hip- and thigh-worn accelerometers agree for older adults. Thigh-worn activPAL (AP) micro monitors were concurrently worn with hip-worn ActiGraph (AG) GT3X+ accelerometers (with SB measured using the 100 counts per minute [cpm] cut point; AG100cpm) by 953 older adults (age 77 ± 6.6, 54% women) for 4–7 days. Device agreement for sedentary time and five SB pattern metrics was assessed using mean error and correlations. Logistic regression tested associations with four health outcomes using standardized (i.e., z scores) and unstandardized SB metrics. Mean errors (AP − AG100cpm) and 95% limits of agreement were: sedentary time −54.7 [−223.4, 113.9] min/day; time in 30+ min bouts 77.6 [−74.8, 230.1] min/day; mean bout duration 5.9 [0.5, 11.4] min; usual bout duration 15.2 [0.4, 30] min; breaks in sedentary time −35.4 [−63.1, −7.6] breaks/day; and alpha −.5 [−.6, −.4]. Respective Pearson correlations were: .66, .78, .73, .79, .51, and .40. Concordance correlations were: .57, .67, .40, .50, .14, and .02. The statistical significance and direction of associations were identical for AG100cpm and AP metrics in 46 of 48 tests, though significant differences in the magnitude of odds ratios were observed among 13 of 24 tests for unstandardized and five of 24 for standardized SB metrics. Caution is needed when interpreting SB metrics and associations with health from AG100cpm due to the tendency for it to overestimate breaks in sedentary time relative to AP. However, high correlations between AP and AG100cpm measures and similar standardized associations with health outcomes suggest that studies using AG100cpm are useful, though not ideal, for studying SB in older adults.
Dhinu J. Jayaseelan, Cesar Fernandez-de-las-Penas, Taylor Blattenberger, and Dean Bonneau
Clinical Scenario: Plantar heel pain is a common condition frequently associated with persistent symptoms and functional limitations affecting both the athletic and nonathletic populations. Common interventions target impairments at the foot and ankle and local drivers of symptoms. If symptoms are predominantly perpetuated by alterations in central pain processing, addressing peripheral impairments alone may not be sufficient. Clinical Question: Do individuals with chronic plantar heel pain demonstrate signs potentially associated with altered central pain processing? Summary of Key Findings: After searching 6 electronic databases (PubMed, CINAHL, Scopus, SportDiscus, Cochrane, and PEDro) and filtering titles based on predetermined inclusion and exclusion criteria, 4 case-control studies were included. All studies scored highly on the Newcastle-Ottawa Scale for quality assessment. Using pressure pain thresholds, each study found decreased pressure pain hypersensitivity locally and at a remote site compared to control groups, suggesting the presence, to some extent, of altered nociceptive pain processing. Clinical Bottom Line: In the studies reviewed, reported results suggest a possible presence of centrally mediated symptoms in persons with plantar heel pain. However, despite findings from these studies, limitations in appropriate matching based on body mass index and measures used suggest additional investigation is warranted. Strength of Recommendation: According to the Oxford Centre for Evidence-Based Medicine, there is evidence level C to suggest chronic plantar heel pain is associated with alterations in central pain processing.
Matthew K. Seeley, Seong Jun Son, Hyunsoo Kim, and J. Ty Hopkins
Context: Patellofemoral pain (PFP) is often categorized by researchers and clinicians using subjective self-reported PFP characteristics; however, this practice might mask important differences in movement biomechanics between PFP patients. Objective: To determine whether biomechanical differences exist during a high-demand multiplanar movement task for PFP patients with similar self-reported PFP characteristics but different quadriceps activation levels. Design: Cross-sectional design. Setting: Biomechanics laboratory. Participants: A total of 15 quadriceps deficient and 15 quadriceps functional (QF) PFP patients with similar self-reported PFP characteristics. Intervention: In total, 5 trials of a high-demand multiplanar land, cut, and jump movement task were performed. Main Outcome Measures: Biomechanics were compared at each percentile of the ground contact phase of the movement task (α = .05) between the quadriceps deficient and QF groups. Biomechanical variables included (1) whole-body center of mass, trunk, hip, knee, and ankle kinematics; (2) hip, knee, and ankle kinetics; and (3) ground reaction forces. Results: The QF patients exhibited increased ground reaction force, joint torque, and movement, relative to the quadriceps deficient patients. The QF patients exhibited: (1) up to 90, 60, and 35 N more vertical, posterior, and medial ground reaction force at various times of the ground contact phase; (2) up to 4° more knee flexion during ground contact and up to 4° more plantarflexion and hip extension during the latter parts of ground contact; and (3) up to 26, 21, and 48 N·m more plantarflexion, knee extension, and hip extension torque, respectively, at various times of ground contact. Conclusions: PFP patients with similar self-reported PFP characteristics exhibit different movement biomechanics, and these differences depend upon quadriceps activation levels. These differences are important because movement biomechanics affect injury risk and athletic performance. In addition, these biomechanical differences indicate that different therapeutic interventions may be needed for PFP patients with similar self-reported PFP characteristics.
Sean Sanford, Mingxiao Liu, and Raviraj Nataraj
Context: Continuous visual feedback (VF) can improve abilities to achieve desired movements and maximize rehabilitation outcomes by displaying actual versus target body positions in real time. Bandwidth VF reduces the reliance on feedback by displaying movement cues only when performance errors exceed specified thresholds. As such, bandwidth VF may better train independent movement abilities through greater development of intrinsic body control. In this study, continuous and bandwidth VF were investigated across modes of display (abstract and representative) that differed in body-discernibility. Objective: To compare the performance of the 2-legged squat during training with concurrent feedback (real-time VF) and short-term retention (immediately after training, VF removed). Design: Cross-sectional. Setting: University research laboratory. Participants: Eighteen healthy individuals. Methods: Marker-based motion capture displayed real-time position. Main Outcome Measures: Four VF cases (continuous–abstract, bandwidth–abstract, continuous–representative, and bandwidth–representative) were evaluated for accuracy and consistency to a target trajectory and target depth. Results: During training, both continuous VF cases showed significantly (P < .05) higher accuracy and consistency to the target trajectory compared with both bandwidth VF cases. Bandwidth VF resulted in greater potential learning (retention performance relative to a training baseline) compared with continuous–abstract. Conclusions: Continuous–representative may offer unique performance benefits in both training and retention of multisegment movement tasks. Bandwidth VF showed greater potential for learning. For long-term learning, an optimal VF paradigm should consider continuous–representative with bandwidth features.
Gabriella Whitcomb-Khan, Nick Wadsworth, Kristin McGinty-Minister, Stewart Bicker, Laura Swettenham, and David Tod
This study explored the experiences of elite athletes during the initial stages of lockdown as a result of the COVID-19 pandemic. The eight recruited participants (three females, five males) were asked to tell a story of their lockdown experience. Narrative analysis was used to explore the athletes’ stories. The athletes’ narrative is best represented in four distinct sections: (a) threat to goals, (b) ongoing consequences, (c) overcoming COVID-19, and (d) adapting to COVID-19. Four narrative themes were also coconstructed from the athletes’ stories: (a) factors athletes found challenging, (b) loss, (c) strategies that benefitted athletes psychologically, and (d) silver linings. Combined, these findings suggest that the initial stages of lockdown are best described as a critical pause. The authors present applied implications for athletes and sport psychology practitioners. The authors also recommend that future research investigate the longitudinal effect of prolonged lockdown on athletes’ lives and a potential return to sport.