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Enrico Perri, Carlo Simonelli, Alessio Rossi, Athos Trecroci, Giampietro Alberti, and F. Marcello Iaia

Purpose: To investigate the relationship between the training load (TL = rate of perceived exertion × training time) and wellness index (WI) in soccer. Methods: The WI and TL data were recorded from 28 subelite players (age = 20.9 [2.4] y; height = 181.0 [5.8] cm; body mass = 72.0 [4.4] kg) throughout the 2017/2018 season. Predictive models were constructed using a supervised machine learning method that predicts the WI according to the planned TL. The validity of our predictive model was assessed by comparing the classification’s accuracy with the one computed from a baseline that randomly assigns a class to an example by respecting the distribution of classes (B1). Results: A higher TL was reported after the games and during match day (MD)-5 and MD-4, while a higher WI was recorded on the following days (MD-6, MD-4, and MD-3, respectively). A significant correlation was reported between daily TL (TLMDi) and WI measured the day after (WIMDi+1) (r = .72, P < .001). Additionally, a similar weekly pattern seems to be repeating itself throughout the season in both TL and WI. Nevertheless, the higher accuracy of ordinal regression (39% [2%]) compared with the results obtained by baseline B1 (21% [1%]) demonstrated that the machine learning approach used in this study can predict the WI according to the TL performed the day before (MD<i). Conclusion: The machine learning technique can be used to predict the WI based on a targeted weekly TL. Such an approach may contribute to enhancing the training-induced adaptations, maximizing the players’ readiness and reducing the potential drops in performance associated with poor wellness scores.

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Teun van Erp, Marcel Kittel, and Robert P. Lamberts

Purpose: To describe the performance and tactical sprint characteristics of a world-class sprinter competing in the Tour de France. In addition, differences in the sprint tactics of 2 teams and won versus lost sprints are highlighted. Method: Power output (PO) and video footage of 21 sprints were analyzed. Position in the peloton and number of teammates supporting the sprinter at different times before the finish line together with PO for different time intervals were determined. Sprints were classified as team Shimano (2013–2014) and team Quick-step (2016–2017), as well as won or lost. Results: The sprinter was highly successful, winning 14 out of the 21 sprints. At time intervals 10 to 5, 3 to 2, and 1.5 to 1 minute, POs were significantly lower in team Quick-step compared with team Shimano, but the sprinter was positioned further away from the front at 10, 2, 1.5, 1, and 0.5 minutes at team Quick-step compared with team Shimano. The PO was higher at time interval 0.5 to 0.25 minutes before the finish line with team Quick-step when compared with team Shimano. The position of the sprinter in the peloton in lost sprints was further away from the front at 0.5 minutes before the finish compared with won sprints, while no differences were noted for PO and the number of teammates between won and lost sprints. Conclusions: Differences in sprint tactics (Shimano vs Quick-step) influence the PO and position in the peloton during the sprint preparation. In addition, the position at 0.5 minutes before the finish line influences the outcome (won or lost) of the sprint.

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Luke Hogarth, Mark McKean, Max McKenzie, and Tyler Collings

Purpose: This study established the relationship between isometric midthigh pull (IMTP) peak force and court-based jumping, sprinting, and change of direction (COD) performance in professional netball players. The change in IMTP peak force in response to sport-specific training was also examined. Methods: IMTP peak force and court-based jumping, sprinting, and COD were collected in 18 female athletes contracted to a Suncorp Super Netball team. Linear regression models established the relationship between absolute and normalized strength values and court-based performance measures in the participant cohort. Changes in IMTP peak force and court-based performance measures were examined following 2 consecutive preseason training blocks in a subset of participants. Results: The IMTP peak force values normalized to body mass were found to be determinants of court-based jumping, sprinting, and COD performance in the participant cohort (R 2 = .34–.65, P ≤ .016). The participants showed increases in absolute (mean ± SE = 398 ± 68.5 N, P < .001, Hedge g = 0.70 [−0.05 to 1.35]) and normalized IMTP peak force (mean ± SE = 4.6 ± 0.78 N·kg−1, P < .001, Hedge g = 0.47 [−0.04 to 0.97]) over 2 consecutive training blocks that coincided with improvements in jumping, sprinting, and COD performances. Conclusion: IMTP peak force is a determinant of court-based jumping, sprinting, and COD performance and is sensitive to training in professional netball players. These results support the utility of the IMTP test to monitor the development and maintenance of maximal lower body muscular strength in these athletes.

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Sarah Labudek, Lena Fleig, Carl-Philipp Jansen, Franziska Kramer-Gmeiner, Corinna Nerz, Clemens Becker, Jochen Klenk, and Michael Schwenk

This study examined the applicability of the health action process approach (HAPA) to walking duration in older adults and the added value of extending the HAPA by intrinsic motivation. Self-reports from older adults (N = 309; M age = 78.7, 70–95 years) regarding activity-related intrinsic motivation and HAPA variables were collected at the baseline of a fall prevention intervention study. Walking duration at ≥3 metabolic equivalents of task was measured for 7 days via body-worn accelerometers. Two structural equation models with walking duration as a manifest outcome were specified. In both models, the model fit was acceptable, but intention and planning were not associated with walking duration. Intrinsic motivation was significantly related to most HAPA variables and walking duration. Variance explained for walking duration was R 2 = .14 in the HAPA and R 2 = .17 in the extended model. For explaining older adults’ walking duration, intrinsic motivation, but not HAPA-based intention and planning, seemed to be important.

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Nathan Morelli, Nicholas R. Heebner, Courtney J. DeFeo, and Matthew C. Hoch

Objective: To determine the influence of a cognitive dual task on postural sway and balance errors during the Concussion Balance Test (COBALT). Methods: Twenty healthy adults (12 females, eight males; aged 21.95 ± 3.77 years; height = 169.95 ± 9.95 cm; weight = 69.58 ± 15.03 kg) partook in this study and completed single- and dual-task versions of a reduced COBALT. Results: Sway velocity decreased during dual-task head rotations on foam condition (p = .021, ES = −0.57). A greater number of movement errors occurred during dual-task head rotations on firm surface (p = .005, ES = 0.71), visual field flow on firm surface (p = .008, ES = 0.68), and head rotations on foam surface (p < .001, ES = 1.61) compared with single-task conditions. Cognitive performance was preserved throughout different sensory conditions of the COBALT (p = .985). Discussion: Cognitive dual tasks influenced postural control and destabilized movements during conditions requiring advanced sensory integration and reweighting demands. Dual-task versions of the COBALT should be explored as a clinical tool to identify residual deficits past the acute stages of concussion recovery.

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Teun van Erp, Marcel Kittel, and Robert P. Lamberts

Purpose: To describe the intensity, load, and performance characteristics of a world-class sprinter competing in the Tour de France (TdF). Method: Power output (PO) data were collected from 4 editions of the TdF (2013, 2014, 2016, and 2017) and analyzed. Load, intensity distribution in 5 PO zones, and the maximal mean PO for multiple durations were quantified. Stages were divided in accordance with the 4 different editions of the TdF, as well as the 4 different stage types, that is, flat (FLAT), semimountainous (SMT), mountain (MT), and (team) time trials. In addition, based on their location within the stage, mountain passes were further classified as BEGINNING, MIDDLE, or END of the stage. Results: No differences in load, intensity, and performance characteristics were found when the 4 editions of the TdF were compared. Time trials were associated with higher intensities but a lower load compared to the other stage types. MT showed higher load and intensity values compared to FLAT and SMT stages. FLAT stages were higher in short maximal mean PO (≤1 min), whereas MT stages showed higher longer endurance maximal mean PO values (≥20 min). In addition, mountain passes situated at the BEGINNING of the stage were completed with a higher PO, cadence, and speed compared with mountain passes situated at the END. Conclusions: A world-class sprinter sustains a higher load and spends more time in the high-intensity zones when competing in the TdF than previously reported values suggested. To finish the MT stages as efficiently as possible, sprinters adopt a reverse pacing strategy.

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Zong-Yan Cai, Wen-Yi Wang, Yi-Ming Huang, and Chih-Min Wu

Purpose: The authors investigated the effect of foot cooling (FC) between sets in a leg press pyramid workout with resistance-trained participants. Methods: A total of 12 resistance-trained men (age = 21.8 [0.6] y; training experience = 1.7 [1] y) performed a pyramid workout, including 4 sets of 85% to 90% 1-repetition maximum leg press exercise to exhaustion with interset FC or noncooling in a repeated-measures crossover design separated by 5 days. The authors immersed the participants’ feet in 10°C water for 2.5 minutes between sets. Results: Two-way repeated-measures analysis of variance revealed that FC elicited significantly higher repetitions and electromyography (EMG) values of the vastus lateralis (simple main effect of condition) than did noncooling (P < .05) in the second (repetitions: 11 [3.5] vs 7.75 [3.2]; EMG: 63.4% [19.4%] vs 54.5% [18.4%]), third (repetitions: 8.9 [3.2] vs 6.4 [2.1]; EMG: 71.5% [17.4%] vs 60.6% [19.4%]), and fourth (repetitions: 7.5 [2.7] vs 5.1 [2.2]; EMG: 75.2% [19.6%] vs 59.3% [23.5%]) sets. The authors also detected a simple main effect of set in the FC and noncooling conditions on repetitions (P < .05) and in the FC condition on the vastus lateralis EMG values. Although the authors observed no time × trial interactions for the rating of perceived exertion, the authors observed main effects on the sets (7.7–9.6 vs 7.9–9.3, P < .05). Conclusions: Interset FC provides an ergogenic effect on a leg press pyramid workout and may offset fatigue, as indicated by higher repetitions and EMG response, without increasing perceived exertion.

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Pablo Nájera-Ferrer, Carlos Pérez-Caballero, Juan José González-Badillo, and Fernando Pareja-Blanco

Purpose: This study aimed to analyze the response to 4 concurrent training interventions differing in the training sequence and in the velocity loss (VL) threshold during strength training (20% vs 40%) on following endurance and strength performance. Methods: A randomized crossover research design was used. Sixteen trained men performed 4 training interventions consisting of endurance training (ET) followed by resistance training (RT), with 20% and 40% VL, respectively (ET + RT20 and ET + RT40), and RT with 20% and 40% VL, respectively, followed by ET (RT20 + ET and RT40 + ET). The ET consisted of running for 10 minutes at 90% of maximal aerobic velocity. The RT consisted of 3 squat sets with 60% of 1-repetition maximum. A 5-minute rest was given between exercises. The oxygen uptake throughout the ET and repetition velocity during RT were recorded. The blood lactate concentration, vertical jump, and squat velocity were measured at preexercise and after the endurance and strength exercises. Results: The RT40 + ET protocol showed an impaired running time along with higher ventilatory equivalents compared with those protocols that performed the ET without previous fatigue. No significant differences were observed in the repetitions per set performed for a given VL threshold, regardless of the exercise sequence. The protocols consisting of 40%VL induced greater reductions in jump height and squat velocity, along with elevated blood lactate concentration. Conclusions: A high VL magnitude (40%VL) induced higher metabolic and mechanical stress, as well as greater residual fatigue, on the following ET performance.

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Manju Daniel, David Marquez, Diana Ingram, and Louis Fogg

Background: South Asian Indian immigrants residing in the United States are at high risk of cardiovascular disease (prevalence ≥35%), diabetes (prevalence 45.4%), and stroke (prevalence 26.5%). This study examined the effect of culturally relevant physical activity interventions on the improvement of physiological measures and average daily steps in at-risk midlife South Asian Indian immigrant women. Methods: In this 2-arm interventional research design, the dance (n = 25) and the motivational phone calls group (n = 25), attended social cognitive theory–based motivational workshops every 2 weeks for the first 12 weeks. Data for weight, waist circumference, blood pressure, blood sugar, cholesterol level, and 12-lead electrocardiogram were collected at the baseline, 12 weeks, and 24 weeks. Results: Significant differences were seen in body weight (F 2,94 = 4.826, P = .024; ηp2=.093), waist circumference (F 2,92 = 7.496, P = .001; ηp2=.140), systolic blood pressure (F 2,94 = 19.865, P = .000; ηp2=.2970), triglyceride (F 2,94 = 11.111, P = .000; ηp2=.191), cholesterol (F 2,94 = 8.925, P = .001; ηp2=.160), blood sugar level (F 2,94 = 8.851, P = .000; ηp2=.158), and average daily steps across both intervention groups over time (F 2,96 = 30.94, P = .000; ηp2=.392). Conclusion: Culturally relevant motivational workshops with Indian dance and walking are an innovative approach to increasing lifestyle physical activity among South Asian Indian immigrant women.