Purpose: The purpose of this study was to investigate the influence of the soccer pitch area during small-sided games (SSG) in prepubertal children on physiological and technical demands, and to compare them, for the physiological demands, to high-intensity interval training (HIIT). Methods: Ten young soccer players (13.0 [0.3] y) performed a HIIT and 3 SSG of various field sizes (30 × 20 m, 42 × 38 m, and 51 × 34 m). Each SSG was performed with 5 players per team, during 4 × 4-minutes interspaced with 1 minute of passive recovery in between. HIIT also followed a 4 × 4-minute protocol with running speed set on an individual basis. Heart rate (HR) was continuously monitored during training sessions. For each exercise modality, time spent above 90% of HRmax (T≥90%,HRmax) was calculated, and technical actions were quantified during SSG by video analysis. Results: T≥90%,HRmax was similar between the 3 SSG (∼587  s; P > .2) but 24% to 37% lower than during HIIT (826  s, P < .05). Coefficients of variations in T≥90%,HRmax were 2.3 to 3.5 times larger in SSG compared with HIIT. For technical actions, greater number of possessions (21  vs ∼14 ), and lower ball touches per possession (2.4 [0.6] vs ∼2.9 [0.6]) were found in the small SSG compared with larger SSG, respectively (P < .05). Conclusion: The 3 SSG led to lower acute stimulation of the aerobic metabolism, suggesting a lower potential for chronic aerobic adaptations, compared with HIIT. Moreover, interindividual variability in the physiological response was substantially greater in SSG compared with HIIT, indicating increased heterogeneity among players performing the same training protocol.
Anasthase Massamba, Stéphane P. Dufour, Fabrice Favret and Thomas J. Hureau
Xabier Muriel, Javier Courel-Ibáñez, Victor Cerezuela-Espejo and Jesús G. Pallarés
Purpose: The COVID-19 outbreak has challenged professional athletes’ training and competition routines in a way not seen before. This report aims to inform about the changes in training volume and intensity distribution and their effects on functional performance due to a 7-week home-confinement period in professional road cyclists from a Union Cycliste Internationale Pro Team. Methods: A total of 18 male professional cyclists (mean [SD] age = 24.9 [2.8] y, body mass = 66.5 [5.6] kg, maximal aerobic power = 449  W; 6.8 [0.6] W/kg) were monitored during the 10 weeks before the lockdown (outdoor cycling) and the 7-week lockdown (indoor cycling turbo trainer). Data from the mean maximal power output (in watts per kilogram) produced during the best 5-minute and best 20-minute records and the training intensity distributions (weekly volumes at power-based training zones) were collected from WKO5 software. Results: Total training volume decreased 33.9% during the lockdown (P < .01). Weekly volumes by standardized zones (Z1 to Z6) declined between 25.8% and 52.2% (effect size from 0.83 to 1.57), except for Z2 (P = .38). There were large reductions in best 5-minute and best 20-minute performance (effect size > 1.36; P < .001) with losses between 1% and 19% in all the cyclists. Conclusions: Total indoor volumes of 12 hours per week, with 6 hours per week at low intensity (Z1 and Z2) and 2 hours per week at high intensity over the threshold (Z5 and Z6), were insufficient to maintain performance in elite road cyclists during the COVID-19 lockdown. Such performance declines should be considered to enable a safe and effective return to competition.
Cristiano D. da Silva and Ric Lovell
Purpose: To examine the physiological, muscle-damage, endocrine, and immune responses to a modified soccer-simulation protocol to include technical and jumping activities characteristic of match play (the Technical Soccer-Specific Aerobic Field Test; T-SAFT90). Methods: Eighteen university players (age 23  y, stature 175  cm, body mass 74  kg) performed the 90-minute protocol, with acute physiological responses monitored via heart rate, ratings of perceived exertion (6–20 scale), and body mass changes. Creatine kinase, myoglobin, cortisol, and leukocyte subset concentrations were measured at baseline, immediately (0 h), and 24 hours post T-SAFT90. Results: T-SAFT90 incurred an average heart rate equivalent to 87% (5%) of maximum, 16 (2) a.u. ratings of perceived exertion, and a 1.5% (1.0%) body mass deficit. Moderate to large proliferation of leukocyte subsets (P ≤ .01; leukocytes: 6.4-fold; neutrophils: 5.5-fold; lymphocytes: 2.0-fold) and increases in cortisol (2.3-fold) were observed at 0 hours (effect size = 1.13–3.52), each returning to baseline by 24 hours (P > .45; effect size = 0.05–0.50). Myoglobin peaked immediately post T-SAFT90 (4.8-fold), whereas creatine kinase (24 h: 6.0-fold) showed a delayed time course (both P ≤ .001; very large effects; effect size = 2.66 and 3.43, respectively). Conclusions: The magnitude and time course of the physiological, immune, endocrine, and muscle-damage markers observed during and following T-SAFT90 are similar to values reported in match-play literature, demonstrating external validity of the simulation.
Jordan L. Fox, Aaron T. Scanlan, Robert Stanton, Cody J. O’Grady and Charli Sargent
Purpose: To examine the impact of workload volume during training sessions and games on subsequent sleep duration and sleep quality in basketball players. Methods: Seven semiprofessional male basketball players were monitored across preseason and in-season phases to determine training session and game workloads, sleep duration, and sleep quality. Training and game data were collected via accelerometers, heart-rate monitors, and rating of perceived exertion (RPE) and reported as PlayerLoad™ (PL), summated heart-rate zones, and session RPE (sRPE). Sleep duration and sleep quality were measured using wrist-worn activity monitors in conjunction with self-report sleep diaries. For daily training sessions and games, all workload data were independently sorted into tertiles representing low, medium, and high workload volumes. Sleep measures following low, medium, and high workloads and control nights (no training/games) were compared using linear mixed models. Results: Sleep onset time was significantly later following medium and high PL and sRPE game workloads compared with control nights (P < .05). Sleep onset time was significantly later following low, medium, and high summated heart-rate-zones game workloads, compared with control nights (P < .05). Time in bed and sleep duration were significantly shorter following high PL and sRPE game workloads compared with control nights (P < .05). Following low, medium, and high training workloads, sleep duration and quality were similar to control nights (P > .05). Conclusions: Following high PL and sRPE game workloads, basketball practitioners should consider strategies that facilitate longer time in bed, such as napping and/or adjusting travel or training schedules the following day.
Thiago Oliveira Borges, Nicola Bullock, David Aitken, Gregory R. Cox and Aaron J. Coutts
Purpose: To compare the metabolic cost of paddling on different commercially available kayak ergometers using a standardized kayak incremental exercise protocol. Methods: Six male sprint kayak athletes undertook an incremental exercise protocol on 3 different kayak ergometers utilizing a randomized counterbalanced pair-matched design. Results: Mean maximal aerobic power on the WEBA ergometer (265  W) was significantly higher than on the Dansprint (238  W) and KayakPro® (247  W, P < .01, effect size [ES] = 0.80). At the fifth stage, absolute oxygen consumption on the WEBA (3.82 [0.25] L·min−1) was significantly lower (P < 0.05, ES = 0.20) than KayakPro and Dansprint (4.10 [0.28] and 4.08 [0.27] L·min−1, respectively). Blood lactate concentration response at the sixth stage was significantly lower for the WEBA (3.5 [0.8] mmol·L−1), compared with KayakPro and Dansprint (5.4 [1.2] and 5.6 [1.5] mmol·L−1, P = .012, ES = 0.20). Stroke rate was significantly higher, without any effect of pacing during the submaximal stages for the Dansprint, compared with the WEBA (P < .001, ES = 0.28) and KayakPro (P < .001, ES = 0.38). A pacing effect was present at the maximal stage for all ergometers. Conclusions: This study demonstrated that paddling on different kayak ergometers when controlling power output elicits different metabolic and work outputs. It is recommended that scientists and coaches avoid testing on different ergometers and regularly calibrate these devices. Moreover, when an ergometer has been calibrated against a first principle device, it is necessary to consider calibration of various drag settings, due to their impact on stroke rate. Further research should explore the relationship between drag settings and stroke rate.
Jordan L. Fox, Cody J. O’Grady and Aaron T. Scanlan
Purpose: To investigate the relationships between external and internal workloads using a comprehensive selection of variables during basketball training and games. Methods: Eight semiprofessional, male basketball players were monitored during training and games for an entire season. External workload was determined as PlayerLoad™: total and high-intensity accelerations, decelerations, changes of direction, and jumps and total low-intensity, medium-intensity, high-intensity, and overall inertial movement analysis events. Internal workload was determined using the summated-heart-rate zones and session rating of perceived exertion models. The relationships between external and internal workload variables were separately calculated for training and games using repeated-measures correlations with 95% confidence intervals. Results: PlayerLoad was more strongly related to summated-heart-rate zones (r = .88 ± .03, very large [training]; r = .69 ± .09, large [games]) and session rating of perceived exertion (r = .74 ± .06, very large [training]; r = .53 ± .12, large [games]) than other external workload variables (P < .05). Correlations between total and high-intensity accelerations, decelerations, changes of direction, and jumps and total low-intensity, medium-intensity, high-intensity, and overall inertial movement analysis events and internal workloads were stronger during training (r = .44–.88) than during games (r = .15–.69). Conclusions: PlayerLoad and summated-heart-rate zones possess the strongest dose–response relationship among a comprehensive selection of external and internal workload variables in basketball, particularly during training sessions compared with games. Basketball practitioners may therefore be able to best anticipate player responses when prescribing training drills using these variables for optimal workload management across the season.
Nick Dobbin, Cari Thorpe, Jamie Highton and Craig Twist
Purpose: To examine the within- and between-sexes physical performance, well-being, and neuromuscular function responses across a 4-day international touch rugby (Touch) tournament. Methods: Twenty-one males and 20 females completed measures of well-being (fatigue, soreness, sleep, mood, and stress) and neuromuscular function (countermovement jump height, peak power output, and peak force) during a 4-day tournament with internal, external, and perceptual loads recorded for all matches. Results: Relative and absolute total, low-intensity (females), and high-intensity distance were lower on day 3 (males and females) (effect size [ES] = −0.37 to −0.71) compared with day 1. Mean heart rate was possibly to most likely lower during the tournament (except day 2 males; ES = −0.36 to −0.74), whereas rating of perceived exertion-training load was consistently higher in females (ES = 0.02 to 0.83). The change in mean fatigue, soreness, and overall well-being was unclear to most likely lower (ES = −0.33 to −1.90) across the tournament for both sexes, with greater perceived fatigue and soreness in females on days 3 to 4 (ES = 0.39 to 0.78). Jump height and peak power output were possibly to most likely lower across days 2 to 4 (ES = −0.30 to −0.84), with greater reductions in females (ES = 0.21 to 0.66). Well-being, countermovement jump height, and peak force were associated with changes in external, internal, and perceptual measures of load across the tournament (η2 = −.37 to .39). Conclusions: Elite Touch players experience reductions in well-being, neuromuscular function, and running performance across a 4-day tournament, with notable differences in fatigue and running between males and females, suggesting that sex-specific monitoring and intervention strategies are necessary.
Aviv Emanuel, Isaac Isur Rozen Smukas and Israel Halperin
Background: Despite the progress made in the study of subjective measures in resistance training, some questions remain unanswered. Here the authors investigated if ratings of perceived exertion (RPE) can predict task failure and bar velocity across exercises and loads as a primary outcome and whether a battery of subjective measures differ as a function of the lifted loads as a secondary outcome. Methods: In this preregistered study, 20 resistance-trained subjects (50% female) first completed a 1-repetition-maximum test of the barbell squat and bench press. In the second and third sessions, they completed 2 sets of squats followed by 2 sets of bench press to task failure, using 70% or 83% of 1-repetition maximum, while bar velocity was recorded. RPE scores were recorded after every repetition. In addition to RPE, rating of fatigue, affective valence, enjoyment, and load preferences were collected after set and session completion. Results: Across conditions, RPE was strongly correlated with reaching task failure (r = .86) and moderately correlated with bar velocity (r = −.58). The model indicates that an increase in 1 RPE unit is associated with an 11% shift toward task failure and a 4% reduction in bar velocity, with steeper slopes observed in the heavier condition. Negligible differences were observed between the load conditions in rating of fatigue, affective valence, enjoyment, and load preference. Conclusion: RPE scores, collected on a repetition-by-repetition basis, accurately reflected reaching task failure across loads and conditions. Hence, RPE can be used to prescribe repetition numbers during ongoing sets. The negligible differences between load conditions in rating of fatigue, affective valence, enjoyment, and load preference indicate that when sets are taken to task failure, loads can be selected based on individual preferences.
Hairui Liu, Wei Wang, Chunhe Zhang and Peter A. Hastie
Purpose: The purpose of this study was to examine the effects of Play Practice (PP) instruction on badminton performance in college students. Method: A total of 66 students from the United States and China participated in units following either the principles of PP or skill-focused instruction. A nonequivalent control/comparison group experimental design with premeasure and postmeasure was used in this study. Separate analyses of variance with repeated measures (Time × Group) were conducted to examine the effects of PP and skill-focused instruction for each of the four dependent variables: (a) forehand clear, (b) wall volley, (c) game performance, and (d) tactical understanding. Results: Both PP and skill-focused instruction conditions were effective in improving participants’ skills from pretest to posttest. However, PP was also effective in improving participants’ game performance. Conclusion: PP effectively developed both fundamental skills and tactical aspects of badminton without diminishing the transfer effect from practice to games.