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Robert MacKenzie, Linda Monaghan, Robert A. Masson, Alice K. Werner, Tansinee S. Caprez, Lynsey Johnston and Ole J. Kemi

Purpose: Rock climbing performance relies on many characteristics. Herein, the authors identified the physical and physiological determinants of peak performance in rock climbing across the range from lower grade to elite. Methods: Forty four male and 33 female climbers with onsight maximal climbing grades 5a–8a and 5a–7b+, respectively, were tested for physical, physiological, and psychological characteristics (independent variables) that were correlated and modeled by multiple regression and principal component analysis to identify the determinants of rock climbing ability. Results: In males, 23 of 47 variables correlated with climbing ability (P < .05, Pearson correlation coefficients .773–.340), including shoulder endurance, hand and finger strength, shoulder power endurance, hip flexibility, lower-arm grip strength, shoulder power, upper-arm strength, core-body endurance, upper-body aerobic endurance, hamstrings and lower-back flexibility, aerobic endurance, and open-hand finger strength. In females, 10 of 47 variables correlated with climbing ability (P < .05, Pearson correlation coefficients .742–.482): shoulder endurance and power, lower-arm grip strength, balance, aerobic endurance, and arm span. Principal component analysis and univariate multiple regression identified the main explanatory variables. In both sexes, shoulder power and endurance measured as maximum pull-ups, average arm crank power, and bent-arm hang, emerged as the main determinants (P < .01; adjusted R 2 = .77 in males and .62 in females). In males, finger pincer (P = .07) and grip strength also had trends (P = .09) toward significant effects. Finally, in test-of-principle training studies, they trained to increase main determinants 42% to 67%; this improved climbing ability 2 to 3 grades. Conclusions: Shoulder power and endurance majorly determines maximal climbing. Finger, hand, and arm strength, core-body endurance, aerobic endurance, flexibility, and balance are important secondary determinants.

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Justin J. Merrigan, James J. Tufano, Jonathan M. Oliver, Jason B. White, Jennifer B. Fields and Margaret T. Jones

Purpose: To examine rest redistribution (RR) effects on back squat kinetics and kinematics in resistance-trained women. Methods: Twelve women from strength and college sports (5.0 [2.2] y training history) participated in the randomized crossover design study with 72 hours between sessions (3 total). Participants completed 4 sets of 10 repetitions using traditional sets (120-s interset rest) and RR (30-s intraset rest in the middle of each set; 90-s interset rest) with 70% of their 1-repetition maximum. Kinetics and kinematics were sampled via force plate and 4 linear position transducers. The greatest value of repetitions 1 to 3 (peak repetition) was used to calculate percentage loss, [(repetition 10–peak repetition)/(peak repetition) × 100], and maintenance, {100–[(set mean–peak repetition)/(peak repetition)] × 100}, of velocity and power for each set. Repeated-measures analysis of variance was used for analyses (P < .05). Results: Mean and peak force did not differ between conditions. A condition × repetition interaction existed for peak power (P = .049) but not for peak velocity (P = .110). Peak power was greater in repetitions 7 to 9 (P < .05; d = 1.12–1.27) during RR. The percentage loss of velocity (95% confidence interval, –0.22% to –7.22%; P = .039) and power (95% confidence interval, –1.53% to –7.87%; P = .008) were reduced in RR. Mean velocity maintenance of sets 3 (P = .036; d = 1.90) and 4 (P = .015; d = 2.30) and mean power maintenance of set 4 (P = .006; d = 2.65) were greater in RR. Conclusion: By redistributing a portion of long interset rest into the middle of a set, velocity and power were better maintained. Therefore, redistributing rest may be beneficial for reducing fatigue in resistance-trained women.

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Andrea Fusco, Christine Knutson, Charles King, Richard P. Mikat, John P. Porcari, Cristina Cortis and Carl Foster

Purpose: Although the session rating of perceived exertion (sRPE) is primarily a marker of internal training load (TL), it may be sensitive to external TL determining factors, such as duration and volume. Thus, sRPE could provide further information on accumulated fatigue not available from markers of internal TL. Therefore, the purpose of this study was to investigate sRPE during heavy training bouts at relatively constant intensity. Methods: Eleven university swimmers performed a high-volume training session consisting of 4 × 10 × 100-yd (4 × 10 × 91.4 m). Repetition lap time and heart rate were measured for each repetition and averaged for each set. Blood lactate concentration was measured after each set. At the end of each set, a 10-minute rest period was allowed, during which sRPE values were obtained, as if the training bout had ended. Results: There were no differences between sets for lap time (P = .096), heart rate (P = .717), and blood lactate concentration (P = .466), suggesting that the subjects were working at the same external and internal intensity. There was an increase (P = .0002) in sRPE between sets (first 4 [1.2], second 5 [1.3], third 7 [1.3], and fourth 8 [1.5]), suggesting that even when maintaining the same intensity, the perception of the entire workload increased with duration. Conclusions: Increases in duration, although performed with a consistent internal and external intensity, influences sRPE. These findings support the concept that sRPE may provide additional information on accumulated fatigue not available from other markers of TL.

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Will Abbott, Callum Brashill, Adam Brett and Tom Clifford

Purpose: To investigate the effects of tart cherry juice (TCJ) on recovery from a soccer match in professional players. Methods: In a double-blind, placebo-controlled, crossover design, 10 male professional soccer players from the reserve team of an English Premier League Club (age 19 [1] y, height 1.8 [0.6] m, body mass 77.3 [6.4] kg) consumed 2 × 30-mL servings of TCJ or an isocaloric cherry-flavored control drink (CON) before and after a 90-minute match and 12 and 36 hours after the match. Muscle function (countermovement jump height and reactive strength index), subjective well-being, and subjective muscle soreness were measured before and 12, 36, and 60 hours after each match. Results: Countermovement jump height was similarly reduced in the days after the match after TCJ and CON supplementation, with the greatest loss occurring at 12-hour postmatch (−5.9% [3.1%] vs −5.4% [2.9%], of baseline values, respectively; P = .966; ηp2=.010). Decrements in reactive strength index were also greatest at 12-hour postmatch (TCJ −9.4% [8.4%] vs CON −13.9% [4.8%], of baseline values), but no group differences were observed at any time point (P = .097; ηp2=.205). Muscle soreness increased 12- to 60-hour postmatch in both groups, peaking at 12-hour postmatch (TCJ 122 [27] mm vs CON 119 [22] mm), but no group differences were observed (P = .808; ηp2=.024). No interaction effects were observed for subjective well-being (P = .874; ηp2=.025). Conclusions: TCJ did not hasten recovery after a soccer match in professional players. These findings bring into question the use of TCJ as a recovery aid in professional soccer players.

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Kristof Kipp, John Krzyszkowski and Daniel Kant-Hull

Purpose: To use an artificial neural network (ANN) to model the effect of 15 weeks of resistance training on changes in countermovement jump (CMJ) performance in male track-and-field athletes. Methods: Resistance training volume load (VL) of 21 male division I track-and-field athletes was monitored over the course of 15 weeks, which covered their indoor and outdoor competitive season. Weekly CMJ height was also measured and used to calculate the overall 15-week change in CMJ performance. A feed-forward ANN with 5 hidden layers was used to model how the VL from each of the 15 weeks was associated with the overall change in CMJ height. Results: Testing the performance of the developed ANN on 4 separate athletes showed that 15 weeks of VL data could predict individual changes in CMJ height with an average error between 0.21 and 1.47 cm, which suggested that the ANN adequately modeled the relationship between weekly VL and its effects on CMJ performance. In addition, analysis of the relative importance of each week in predicting changes in CMJ height indicated that the VLs during deload or taper weeks were the best predictors (10%–17%) of changes in CMJ performance. Conclusions: ANN can be used to effectively model the effects of weekly VL on changes in CMJ performance. In addition, ANN can be used to assess the relative importance of each week in predicting changes in CMJ height.

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Nathan A. Lewis, Andrew J. Simpkin, Sarah Moseley, Gareth Turner, Mark Homer, Ann Redgrave, Charles R. Pedlar and Richard Burden

Background: Identifying strategies that reduce the risk of illness and injury is an objective of sports science and medicine teams. No studies have examined the relationship between oxidative stress (OS) and illness or injury in international athletes undergoing periods of intensified training and competition. Purpose: The authors aimed to identify relationships between illness, injury, and OS. Methods: A longitudinal, observational study of elite male rowers (n = 10) was conducted over 18 weeks, leading into World Championships. Following a recovery day and a 12-hour fast, hydroperoxides (free oxygen radicals test) and total antioxidant capacity (free oxygen radicals defense) were measured in venous blood, with the ratio calculated as the oxidative stress index (OSI). At all study time points, athletes were independently dichotomized as ill or not ill, injured or not injured. OS data were compared between groups using independent t tests. A Cox proportional hazard model was used to assess the association of OS with injury and illness while adjusting for age and body mass index. Results: Free oxygen radicals defense was lower (P < .02) and OSI was higher (P < .001) with illness than without illness. Free oxygen radicals test and OSI were higher with injury than without injury (P < .001). A 0.5 mmol·L−1 increase in free oxygen radicals defense was associated with a 30.6% illness risk reduction (95% confidence interval, 7%–48%, P = .014), whereas 0.5 unit increase in OSI was related to a 11.3% increased illness risk (95% confidence interval, 1%–23%, P = .036). Conclusions: OS is increased in injured and ill athletes. Monitoring OS may be advantageous in assessing recovery from and in reducing injury and illness risk given the association.

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Håvard Wiig, Thor Einar Andersen, Live S. Luteberget and Matt Spencer

Purpose: To investigate within-player effect, between-player effect, and individual response of external training load from player tracking devices on session rating of perceived exertion training load (sRPE-TL) in elite football players. Methods: The authors collected sRPE-TL from 18 outfield players in 21 training sessions. Total distance, high-speed running distance (>14.4 m/s), very high-speed running distance (>19.8 m/s), PlayerLoad, PlayerLoad2D, and high-intensity events (HIE > 1.5, HIE > 2.5, and HIE > 3.5 m/s) were extracted from the tracking devices. The authors modeled within-player and between-player effects of single external load variables on sRPE-TL, and multiple levels of variability, using a linear mixed model. The effect of 2 SDs of external load on sRPE-TL was evaluated with magnitude-based inferences. Results: Total distance, PlayerLoad, PlayerLoad2D, and HIE > 1.5 had most likely substantial within-player effects on sRPE-TL (100%–106%, very large effect sizes). Moreover, the authors observed likely substantial between-player effects (12%–19%, small to moderate effect sizes) from the majority of the external load variables and likely to very likely substantial individual responses of PlayerLoad, high-speed running distance, very high-speed running distance, and HIE > 1.5 (19%–30% coefficient of variation, moderate to large effect sizes). Finally, sRPE-TL showed large to very large between-session variability with all external load variables. Conclusions: External load variables with low intensity-thresholds had the strongest relationship with sRPE-TL. Furthermore, the between-player effect of external load and the individual response to external load advocate for monitoring sRPE-TL in addition to external load. Finally, the large between-session variability in sRPE-TL demonstrates that substantial amounts of sRPE-TL in training sessions are not explained by single external load variables.

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Enrique Colino, Jorge Garcia-Unanue, Leonor Gallardo, Carl Foster, Alejandro Lucia and Jose Luis Felipe

Purpose: To characterize, for the first time, the mechanical properties of treadmill surfaces along with a practical interpretation of their influence on physiological and perceived demands during endurance running compared with other widely used surfaces such as asphalt and tartan tracks. Methods: Ten experienced male endurance runners performed a 40-minute running bout at a preferred constant speed on 3 different surfaces (after a randomized, counterbalanced order with a 7-d interval between trials): asphalt, tartan, or treadmill. Shock absorption, vertical deformation, and energy restitution were measured for the 3 surfaces. Intensity (based on heart rate data) and rating of perceived exertion were monitored. Results: The values of shock absorption averaged 0.0% (asphalt), 37.4% (tartan), and 71.3% (treadmill), while those of vertical deformation and energy restitution averaged 0.3, 2.2, and 6.5 mm and 90.8%, 62.6%, and 37.0%, respectively. Running intensity (as determined by heart rate data) was higher overall on the treadmill than tartan but not asphalt running. Except for the first 10 minutes, all mean rating of perceived exertion values were significantly higher in asphalt and treadmill than in tartan. No significant differences were identified between treadmill and asphalt. Conclusions: The considerably higher shock absorption of the treadmill than the tartan surface leads to a reduction in the amount of energy returned to the athlete, which in turn increases physiological stress and rating of perceived exertion during endurance running.

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Guro Strøm Solli, Espen Tønnessen and Øyvind Sandbakk

Purpose: To investigate the factors associated with underperformance and the subsequent changes in training characteristics and supportive actions when returning to the world’s best cross-country skier. Methods: The participant is the most decorated winter Olympian, with 8 Olympic gold medals, 18 World Championship titles, and 114 World Cup victories. Training data were categorized by training form (endurance, strength, and speed); intensity (low, moderate, and high); and mode (running, cycling, and skiing/roller skiing). In addition, test data were retrospectively analyzed, and interviews were performed with the participant and her support team. Results: After the competitive season, the participant had 8 weeks without systematic training and an evaluation process aiming to detect the factors contributing to underperformance. Here physiological, technical, and psychological challenges were detected. As a consequence, the participant included less high-intensity training (1.2 vs 2.1 sessions/wk, P = .011); more moderate-intensity training (0.9 vs 0.4 sessions/wk, P = .016); and more low-intensity training (6.9 vs 5.9 sessions/wk, P = .036) during the general preparation phase but with similar total endurance training load as previous season. In addition, more strength training (1.6 vs 1.1 h/wk, P = .036) and new ski-specific strength exercises were included. Finally, the athlete’s autonomy when planning and adjusting training was increased, nontraining stressors were reduced, more frequent testing was included, systematic mental training was initiated, her nutritional strategy was adjusted, and her asthma treatment was optimized. Conclusions: Overall, the current case study could be used as a framework for the holistic approach to treating an overtraining condition and for generation of new hypothesis in this exiting area.