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Kerry McGawley, Matt Spencer, Anna Olofsson, and Erik P. Andersson

Context: Warming up in very cold climates and maintaining an elevated body temperature prior to a race is challenging for snow-sport athletes. Purpose: To investigate the effects of active (ACT), passive (PAS), and a combination of ACT and PAS (COM) warm-ups on maximal physical performance in a subzero environment among snow-sport athletes. Methods: Ten junior alpine skiers completed 3 experimental trials in −7.2 (0.2)°C. The ACT involved 5 minutes of moderate cycling, 3 × 15-second accelerations, a 6-second sprint, 5 countermovement jumps (CMJs), and a 10-minute passive transition phase, while in PAS, participants wore a lower-body heated garment for 24 minutes. In COM, participants completed the active warm-up, then wore the heated garment during the transition phase. Two maximal CMJs and a 90-second maximal isokinetic cycling test followed the warm-up. Results: CMJ performance was likely (P = .150) and very likely (P = .013) greater in ACT and COM, respectively, versus PAS. Average power output during the cycling test was likely (P = .074) greater in ACT and COM versus PAS. Participants felt likely to almost certainly warmer (P < .01) and more comfortable (P = .161) during ACT and COM versus PAS. In addition, participants felt likely warmer (P = .136) and very likely more comfortable (P = .161) in COM versus ACT. Conclusions: COM resulted in significantly improved CMJ performance versus PAS while both ACT and COM led to likely improved 90-second cycling performance. Participants felt significantly warmer during ACT and COM versus PAS and likely warmer in COM versus ACT. Therefore, a combined warm-up is recommended for alpine skiers performing in subzero temperatures.

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Oliver J. Chrzanowski-Smith, Robert M. Edinburgh, Mark P. Thomas, Aaron Hengist, Sean Williams, James A. Betts, and Javier T. Gonzalez

This study explored lifestyle and biological determinants of peak fat oxidation (PFO) during cycle ergometry, using duplicate measures to account for day-to-day variation. Seventy-three healthy adults (age range: 19–63 years; peak oxygen consumption [V˙O2peak]:42.4[10.1]ml·kgBM1·min1; n = 32 women]) completed trials 7–28 days apart that assessed resting metabolic rate, a resting venous blood sample, and PFO by indirect calorimetry during an incremental cycling test. Habitual physical activity (combined heart rate accelerometer) and dietary intake (weighed record) were assessed before the first trial. Body composition was assessed 2–7 days after the second identical trial by dual-energy X-ray absorptiometry scan. Multiple linear regressions were performed to identify determinants of PFO (mean of two cycle tests). A total variance of 79% in absolute PFO (g·min−1) was explained with positive coefficients for V˙O2peak (strongest predictor), FATmax (i.e the % of V˙O2peak that PFO occurred at), and resting fat oxidation rate (g·min−1), and negative coefficients for body fat mass (kg) and habitual physical activity level. When expressed relative to fat-free mass, 64% of variance in PFO was explained: positive coefficients for FATmax (strongest predictor), V˙O2peak, and resting fat oxidation rate, and negative coefficients for male sex and fat mass. This duplicate design revealed that biological and lifestyle factors explain a large proportion of variance in PFO during incremental cycling. After accounting for day-to-day variation in PFO, V˙O2peak and FATmax were strong and consistent predictors of PFO.

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Thomas I. Gee, Paul Harsley, and Daniel C. Bishop

Purpose: This study investigated the effects of complex-paired and reverse-contrast 10-week training programs on sprint, power, and change-of-direction speed performance of elite academy soccer players. Methods: Seventeen elite academy soccer players each performed assessments of the 10- and 40-m sprint, Abalakov vertical jump, seated medicine-ball throw, and Arrowhead change-of-direction speed test, both prior to and after a twice-weekly 10-week resistance-training program. The participants were randomly split into 2 groups; the complex-paired training group (CPT, n = 9) performed 4 different complex pairs (heavy-resistance exercises paired with plyometric and Olympic lifting–style exercises), with each pair being interspersed with an 8-minute recovery period in line with recommended guidelines. The comparative group—the reverse-contrast training group (RCT, n = 8)—performed the same exercises; however, all of the plyometric and Olympic lifting exercises preceded the heavy-resistance exercises. Results: Both groups achieved postintervention increases in the seated medicine-ball throw test (CPT +1.8% and RCT +1.6%, P < .05), whereas VJ performance improved only in the CPT group (+3.4%, P = .003). No significant improvements were observed in either the 10- and the 40-m sprint or Arrowhead change-of-direction speed test for either group. Conclusions: The CPT experienced a small but significant within-group improvement in jump performance. However, no significant between-groups differences were observed in any of the testing variables postintervention. Subsequently, for academy soccer athletes, the CPT approach did not produce meaningful benefits to performance compared with a more time-efficient reverse-contrast approach.

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Andrew M. Holwerda, Jorn Trommelen, Imre W.K. Kouw, Joan M. Senden, Joy P.B. Goessens, Janneau van Kranenburg, Annemie P. Gijsen, Lex B. Verdijk, and Luc J.C. van Loon

Protein ingestion and exercise stimulate myofibrillar protein synthesis rates. When combined, exercise further increases the postprandial rise in myofibrillar protein synthesis rates. It remains unclear whether protein ingestion with or without exercise also stimulates muscle connective tissue protein synthesis rates. The authors assessed the impact of presleep protein ingestion on overnight muscle connective tissue protein synthesis rates at rest and during recovery from resistance-type exercise in older men. Thirty-six healthy, older men were randomly assigned to ingest 40 g intrinsically L-[1-13C]-phenylalanine and L-[1-13C]-leucine-labeled casein protein (PRO, n = 12) or a nonprotein placebo (PLA, n = 12) before going to sleep. A third group performed a single bout of resistance-type exercise in the evening before ingesting 40 g intrinsically-labeled casein protein prior to sleep (EX+PRO, n = 12). Continuous intravenous infusions of L-[ring- 2H5]-phenylalanine and L-[1-13C]-leucine were applied with blood and muscle tissue samples collected throughout overnight sleep. Presleep protein ingestion did not increase muscle connective tissue protein synthesis rates (0.049 ± 0.013 vs. 0.060 ± 0.024%/hr in PLA and PRO, respectively; p = .73). Exercise plus protein ingestion resulted in greater overnight muscle connective tissue protein synthesis rates (0.095 ± 0.022%/hr) when compared with PLA and PRO (p < .01). Exercise increased the incorporation of dietary protein-derived amino acids into muscle connective tissue protein (0.036 ± 0.013 vs. 0.054 ± 0.009 mole percent excess in PRO vs. EX+PRO, respectively; p < .01). In conclusion, resistance-type exercise plus presleep protein ingestion increases overnight muscle connective tissue protein synthesis rates in older men. Exercise enhances the utilization of dietary protein-derived amino acids as precursors for de novo muscle connective tissue protein synthesis during overnight sleep.

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Nick Dobbin, Anthony Atherton, and Colin Hill

Purpose: To determine if small-sided games (SSGs) could be designed to target specific task loads using the National Aeronautics and Space Administration task load index as well as reporting the influence of the physical and technical demands. Methods: Using a within-session, repeated-measures design, 26 junior rugby league players completed 5 SSGs focused on physical, technical, temporal, cognitive, and frustration task loads. National Aeronautics and Space Administration task load index responses were evaluated after each game; the physical demands were recorded using microtechnology; and skill involvement recorded using video analysis. Results: In each SSG, the task load emphasized (eg, physical load/physical game) emerged with a higher score than the other loads and SSGs. The physical demands were lowest during the physical game (effect size = −3.11 to 3.50) and elicited greater defensive involvements (effect size = 0.12 to 3.19). The highest physical demands and attacking involvements were observed during the temporal game. Lower intensity activities were generally negatively associated with physical, performance, temporal, and total load (η 2 = −.07 to −.43) but positively associated with technical, effort, cognitive, and frustration (η 2 = .01 to .33). Distance covered in total and at higher speeds was positively associated with physical, effort, performance, total load (η 2 = .18 to .65), and negatively associated with technical, frustration, and cognitive load (η 2 = −.10 to −.36). Attacking and defensive involvements generally increased the respective task loads (η 2 = .03 to .41). Conclusion: Coaches and sport scientists can design SSGs specifically targeted at subjective task loads in a sport-specific manner and through manipulation of the physical and technical demands.

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Irineu Loturco, Lucas A. Pereira, Tomás T. Freitas, Chris Bishop, Fernando Pareja-Blanco, and Michael R. McGuigan

Purpose: To test the relationships between maximum and relative strength (MS and RS), absolute and relative peak force (PF and RPF), and strength deficit (SDef), with sprint and jump performance, and to compare these mechanical variables between elite sprinters and professional rugby union players. Methods: Thirty-five male rugby union players and 30 male sprinters performed vertical jumps, 30-m sprint, and half-squat 1-repetition maximum (1RM), where these force-related parameters were collected. Pearson correlation coefficients were used to test the relationships between the variables. An independent t test and magnitude-based inferences compared the mechanical variables between sprinters and rugby players. Results: Almost certain significant differences were observed for jump and sprint performance between groups (P < .0001). The rugby union players demonstrated a likely significant higher MS (P = .03) but a very likely lower RS (P = .007) than the sprinters. No significant differences were observed for PF between them. The sprinters exhibited an almost certain significant higher RPF than the rugby players (P < .0001). Furthermore, the rugby players demonstrated almost certain to likely significant higher SDef from 40% to 70% 1RM (P < .05) compared with the sprinters. Overall, all strength-derived parameters were significantly related to functional performance. Conclusions: Elite sprinters present higher levels of RS and RPF, lower levels of SDef, and better sprint and jump performance than professional rugby players. Relative strength-derived values (RS and RPF) and SDef are significantly associated with speed–power measures and may be used as effective and practical indicators of athletic performance.

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Marie-Pier McSween, Katie L. McMahon, Kylie Maguire, Jeff S. Coombes, Amy D. Rodriguez, Kirk I. Erickson, and David A. Copland

Recent studies show positive effects of acute exercise on language learning in young adults with lower baseline learning abilities; however, this is yet to be investigated in older adults. This study investigated the acute effects of different exercise intensities on new word learning in healthy older adults with lower and higher baseline learning abilities. Sixty older adults (mean age = 66.4 (4.6); 43 females) performed either a single bout of stretching exercise, moderate-intensity continuous exercise, or high-intensity interval exercise followed by a word learning task. In lower baseline learners, between-group differences were observed on immediate new word recall success, with the moderate-intensity continuous exercise group performing better than the stretching group. These findings suggest immediate benefits of moderate-intensity continuous exercise that are limited to word learning performance of older adults with lower baseline learning abilities. Further investigation into underlying mechanisms could lead to a better understanding of individual differences in responding to acute exercise.

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Pauline Manon Genin, Céline Lambert, Benjamin Larras, Bruno Pereira, Jean-François Toussaint, Julien Steven Baker, Angelo Tremblay, David Thivel, and Martine Duclos

Background: The French National Observatory for Physical Activity and Sedentary Behaviors conducted a national survey aiming to evaluate the potential effects of confinement on the population’s physical activity levels and sedentary behaviors. Methods: In close collaboration with the French Ministry of Sports and a selected expert committee, 3 different questionnaires investigating 3 subgroup populations were included in the survey: (1) children, (2) adolescents, and (3) adults. Results: Forty-two percentage of children, 58.7% of adolescents, 36.4% of adults, and 39.2% of older people had reduced physical activity levels. Particularly, active transportation and endurance practices showed a significant decrease, while domestic, muscular strengthening, and flexibility activities increased. Sitting time and screen time increased, respectively, in 36.3% and 62.0% of children, 25.5% and 69.0% in adolescents, 24.6% and 41.0% in adults, and 36.1% and 32.1% in seniors. Conclusion: The COVID-19 confinement period led to important modifications in individual movement behaviors at all ages, particularly favoring decreased physical activity and increased sedentariness. These findings suggest that the authors need to inform and encourage people to maintain and improve their physical activities and to change their sedentary time habits during postconfinement and during the period of a potential future lockdown.

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Sara Almeida, Cátia Paixão, Madalena Gomes da Silva, and Alda Marques

The objective of this study was to explore the feasibility and preliminary effectiveness of the Lifestyle-Integrated Functional Exercise for People with Dementia (LiFE4D) on health-related physical fitness, cognitive function, physical activity, and respiratory and upper limb functions. A randomized controlled pilot study was conducted (control group: usual care; experimental group: usual care and LiFE4D). The feasibility of LiFE4D was determined considering recruitment, protocol acceptability, adherence, and safety. Measures of health-related physical fitness, cognitive function, physical activity, and respiratory and upper limb functions were assessed at the baseline and 3 months. Twelve participants (8 [66.7%] female, 82 [72.2–84] years) were included, six per group. Recruitment was challenging. LiFE4D was acceptable with excellent adherence and no major adverse events. Cardiorespiratory endurance (effect size = 1.64, 95% confidence interval [CI; 0.33, 2.95]) and balance (effect size = 1.46, 95% CI [0.19, 2.73]) improved after LiFE4D. LiFE4D seems to be feasible and safe, and it shows potential to significantly improve the health-related physical fitness of people with dementia.

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Rihab Borji, Firas Zghal, Nidhal Zarrouk, Sonia Sahli, and Haithem Rebai

The authors explored neuromuscular fatigue in athletes with intellectual disability (AID) compared with sedentary individuals with intellectual disability (SID) and individuals with typical development. Force, voluntary activation level, potentiated resting twitch, and electromyography signals were assessed during isometric maximal voluntary contractions performed before and immediately after an isometric submaximal exhaustive contraction (15% isometric maximal voluntary contractions) and during recovery period. AID presented shorter time to task failure than SID (p < .05). The three groups presented similar isometric maximal voluntary contraction decline and recovery kinetic. Both groups with intellectual disability presented higher voluntary activation level and root mean square normalized to peak-to-peak M-wave amplitude declines (p < .05) compared with individuals with typical development. These declines were more pronounced in SID (p < .05) than in AID. The AID recovered their initial voluntary activation level later than controls, whereas SID did not. SID presented lower potentiated resting twitch decline compared with AID and controls with faster recovery (p < .05). AID presented attenuated central fatigue and accentuated peripheral fatigue compared with their sedentary counterparts, suggesting a neuromuscular profile close to that of individuals with typical development.