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Objectives: To investigate whether tethered swimming (TS) performed 8 minutes before a 50-m freestyle swimming sprint could be an effective postactivation potentiation method to improve performance in young swimmers. Methods: Fourteen regional-level male adolescent swimmers (age 13.0 [2.0] y; height 161.1 [12.4] cm; body mass 52.5 [9.5] kg) underwent 2 trial conditions in a randomized and counterbalanced order (1 experimental [TS], 1 control) on different days. During the experimental session, the participants performed a standard warm-up of 1200 m followed by a TS exercise, which consisted of 3 × 10-second maximal efforts of TS with 1-minute rests between bouts. In the control condition, the warm-up phase was immediately followed by 200 m at a moderate pace (same duration as the TS in the experimental session). Performance (time trial); biomechanical (stroke length), physiological (blood lactate concentrations), and psychophysiological (ratings of perceived exertion) variables; and countermovement-jump (CMJ) flight time were collected. Results: TS warm-up had no significant effect on 50-m swimming performance (P =.27), postexercise ratings of perceived exertion, stroke length, or CMJ flight time (P ≥.05). Blood lactate concentrations significantly increased at the end of the warm-up in the TS condition only (interaction effect: F1.91,29.91 = 4.91, P =.01, η2 =.27) and after the 50-m trial in both conditions (F1.57,20.41 = 62.39, P =.001, η2 =.82). Conclusions: The present study demonstrated that 3 × 10-second TS exercises performed 8 minutes prior to the event did not affect ratings of perceived exertion, stroke length, or CMJ flight time. In addition, tethered swimming did not affect 50-m freestyle sprint performance in young swimmers. [ABSTRACT FROM AUTHOR]

The aim of the study was to assess the validity and reliability of wearable body metric Hexoskin "smart shirt" in measuring heart rate (HR) at pre-exercise and during peak effort in a field test incorporating vigorous movements of the upper body. Measurements were recorded simultaneously using the Hexoskin and Polar Team Pro. Nine male professional handball players (age: 21.8 ± 2.4 years; weight: 83 ± 10.26 kg; height: 1.81 ± 0.09 m; and BMI: 25.17 ± 2.23) volitionally participated in the study by completing two 400 m shuttle run test trials (10 shuttles), each separated by a 48 to 72 h recovery period. Results indicated significant correlations between Hexoskin and Polar Team Pro system in pre-exercise HR. Hexoskin provided erroneous measurements in four of the nine athletes during peak effort. Subsequent correction yielded no consistency between the Polar Team Pro system and Hexoskin between the first and the second trial. Hexoskin showed significant reliability in pre-exercise HR. However, Hexoskin picked up excessive artifact during vigorous physical activity in four of the nine athletes rendering the results in these cases useless. Nevertheless, in athletes where artifact was not an issue, ICC yielded a good estimate. The main findings indicate that Hexoskin has good validity and reliability in measuring pre-exercise HR in handball players and hence may be used with high confidence in slow motion activities. However, vigorous physical activity with jarring multidirectional upper body movements posed a challenge for Hexoskin. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of the study was to investigate performance, biomechanical, physiological, and psychophysiological effects of a simple and easily organized post-activation potentiation (PAP) re-warm-up performed before a 50-m freestyle swimming sprint. Methods: Regional level male adolescent swimmers [age: 13.0 ± 2.0 years; (min 11 years - max 15 years)] performed four trial conditions (three experimental, one control) on different days. The control trial involved a standardized 1200-m warm-up followed by 30 min of rest and a maximal 50-m freestyle swimming sprint. The experimental trials involved the same protocol but added a PAP component after a 20-min rest (10 min pre-50-m): The different PAP component involved the subjects in completing a 30-s maximal effort of: (1) push-ups (PU - upper body), (2) squats (SQ - lower body), and (3) burpees (BP - lower and upper body). Performance (time-trial), biomechanical (stroke length, stroke frequency), physiological (blood lactate concentrations, heart rate), and psychophysiological (ratings of perceived exertion) variables were collected. Results: The results demonstrated that the PAP protocols used in this investigation had no effect on swimming performance. Before the 50-m swimming sprint, the lactate values were significantly higher after the PU, BP, and SQ PAP loads compared to the control condition [P (CC-PU) = 0.02; P (CC-BP) = 0.01; P (CC-SQ) = 0.04]. For Lactate values, a significant and large effect of experimental condition compared to control condition was found ( p < 0.05, η 2 = 0.68). At 1 min after the 50-m time trial, significant differences were observed between the control condition and the different PAP loads [P (CC-PU) = 0.01; P (CC-BP) = 0.04; P (CC-SQ) = 0.01]. At 3 min after the 50-m sprint, significant differences were found between the control condition and the PU and SQ PAP loads [P (CC-PU) = 0.018; P (CC-SQ) = 0.008, respectively]. Additionally, a significant and large effect of experimental condition was found at 1 and 3 min after the 50-m swimming sprint ( p < 0.05, η 2 (1 min) = 0.73; η 2 (3 min) = 0.59). There were medium sized but non-significant effects of interaction between the conditions, was illustrated for the mean HR values in response to the different conditions ( p > 0.05; η 2 = 0.083). Conclusion: None of the three PAP protocols showed any significant improvement in performance, biomechanical, physiological, and psychophysiological variables before, during and after the 50-m swimming time-trial. Further studies are warranted to investigate ways to improve swimming performance with simple body mass exercises performed in-between the end of pool warm-up and race start.