Effect of combined uphill-downhill sprint training on kinematics and maximum running speed in experienced sprinters

This study examined the effects of sprint running training on sloping surfaces (3°) in experienced sprinters using selected kinematic variables. Twelve experienced sprinters were randomly allocated to two training groups (combined uphill–downhill and horizontal). Pre- and post-training tests were performed to examine the effects of six weeks of training on maximum running speed, step rate, step length, step time, contact time, braking and propulsive phase of contact time, flight time and selected postural characteristics during a step cycle in the final steps of a 35m sprint test. In the combined uphill–downhill training group, maximum running speed was substantially greater (from 9.08 ± 0.90 m s-1 to 9.51 ± 0.62 m s-1; p <0.05) after training by 4.8%; step rate, contact time, step time and concentric phase was not modified. There were no significant changes in maximal speed or sprint kinematics in the horizontal training group. Overall, the posture characteristics did not change with training. The combined uphill–downhill training method was substantially more effective in improving the maximum running speed in experienced sprinters than a traditional horizontal training method

A biomechanical and physiological evaluation of combined uphill-downhill sprint running training

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Influence of lower limb dominance on mechanical asymmetries during high-speed treadmill running

We determine whether mechanical asymmetries differ between dominant and non-dominant legs at fast treadmill speed. Stride temporal variables, derived from high-speed camera recordings, allowed to estimate leg and vertical stiffness through the sine-wave method in 31 uninjured males during treadmill running at 6.67 m.s−1. Lower limb dominance was determined by the triple-jump test. The asymmetry was expressed as dominant—non-dominant and indexed by the absolute asymmetry index (ASI). The lowest and highest mean ASI values were detected for contact time (1.69%) and flight time (5.66%), respectively; ASI values for spring-mass characteristics (2.6% ≤ leg and vertical stiffness, peak vertical force, change in vertical leg length and centre of mass vertical displacement ≤ 4.7%) were within this range. Inter-subject variability in ASI varied substantially among the seven analysed variables with larger and smaller range of variability in ASI found for flight time (0–16.56%) and contact time (0–3.47%), respectively. Because the magnitude of group mean ASI appears inconsistent among stride temporal and spring-mass characteristics, different biomechanical variables should not be used interchangeably to assess laterality effects at fast treadmill speed. The widespread ASI range also indicates that using a ‘fixed cut-off’ threshold is an arbitrary approach. © 2021 Informa UK Limited, trading as Taylor &amp; Francis Group

Effect of combined uphill-downhill sprint training on kinematics and maximum running speed in experienced sprinters

This study examined the effects of sprint running training on sloping surfaces (3°) in experienced sprinters using selected kinematic variables. Twelve experienced sprinters were randomly allocated to two training groups (combined uphill-downhill and horizontal). Pre- and post-training tests were performed to examine the effects of six weeks of training on maximum running speed, step rate, step length, step time, contact time, braking and propulsive phase of contact time, flight time and selected postural characteristics during a step cycle in the final steps of a 35m sprint test. In the combined uphill-downhill training group, maximum running speed was substantially greater (from 9.08 ± 0.90 m s-1 to 9.51 ± 0.62 m s-1; p &lt;0.05) after training by 4.8%; step rate, contact time, step time and concentric phase was not modified. There were no significant changes in maximal speed or sprint kinematics in the horizontal training group. Overall, the posture characteristics did not change with training. The combined uphill-downhill training method was substantially more effective in improving the maximum running speed in experienced sprinters than a traditional horizontal training method

Assessment of accuracy, reliability and force measurement errors for a tethered swimming apparatus

Researchers frequently use purpose-built devices to calculate propulsive forces during tethered swimming. Although such devices are subject to force measurement errors, no specific methods have been suggested in the swimming literature for the estimation of these errors. The purpose of this study was to access the accuracy and reliability of a portable device that is used to measure propulsive forces in tethered swimming, and to estimate the errors caused by hysteresis, sensitivity and linearity. The force values recorded during a maximum front crawl test of an international level swimmer were used to provide an example of the extent to which measurement errors could affect the values collected during a tethered swimming study. The calculations revealed small and acceptable errors. When summing the errors from all sources, the total errors affecting the minimum, average and peak forces recorded during the case study were 1.15%, 0.94% and 0.86% respectively. It is recommended that investigators always calculate and report such errors for tethered swimming studies. The methods used in the present study are reasonably simple and not time-consuming, and could be used when assessing errors for similar tethered swimming devices. © 2011, Centre for Performance Analysis. All rights reserved

Combined uphill and downhill sprint running training is more efficacious than horizontal

Purpose: This study examined the effects of sprint running training on sloping surfaces (3°) on selected kinematic and physiological variables. Methods: Fifty-four sport and physical education students were randomly allocated to one of two training groups (combined uphill-downhill [U+D] and horizontal (H)) and a control group (C). Pre- and posttraining tests were performed to examine the effects of 8 wk of training on the maximum running speed (MRS), step rate, step length, step time, contact time, eccentric and concentric phase of contact time (EP, CP), fight time, selected posture characteristics of the step cycle, and 6-s maximal cycle sprint test. Results: MRS, step rate, contact time, and step time were improved significantly in a 35-m sprint test for the U+D group (P &lt;.01) after training by 4.3%, 4.3%, -5.1%, and -3.9% respectively, whereas the H group showed smaller improvements, (1.7% (P &lt;.05), 1.2% (P &lt;.01), 1.7% (P &lt;.01), and 1.2% (P &lt;.01) respectively). There were no significant changes in the C group. The posture characteristics and the peak anaerobic power (AWT) performance did not change with training in any of the groups. Conclusion: The U+D training method was significantly more effective in improving MRS and the kinematic characteristics of sprint running than a traditional horizontal training method. © 2009 Human Kinetics, Inc

Physiological responses of continuous and intermittent swimming at critical speed and maximum lactate steady state in children and adolescent swimmers

Background: The purpose of this study was to compare physiological responses during continuous and intermittent swimming at intensity corresponding to critical speed (CS: slope of the distance vs. time relationship using 200 and 400-m tests) with maximal lactate steady state (MLSS) in children and adolescents. Methods: CS and the speed corresponding to MLSS (sMLSS) were calculated in ten male children (11.5 ± 0.4 years) and ten adolescents (15.8 ± 0.7 years). Blood lactate concentration (BL), oxygen uptake ( ˙VO2), and heart rate (HR) at sMLSS were compared to intermittent (10 × 200-m) and continuous swimming corresponding to CS. Results: CS was similar to sMLSS in children (1.092 ± 0.071 vs. 1.083 ± 0.065 m·s−1; p = 0.12) and adolescents (1.315 ± 0.068 vs. 1.297 ± 0.056 m·s−1; p = 0.12). However, not all swimmers were able to complete 30 min at CS and BL was higher at the end of continuous swimming at CS compared to sMLSS (children: CS: 4.0 ± 1.8, sMLSS: 3.4 ± 1.5; adolescents: CS: 4.5 ± 2.3, sMLSS: 3.1 ± 0.8 mmol·L−1; p &amp;lt; 0.05). ˙VO2 and HR in continuous swimming at CS were not different compared to sMLSS (p &amp;gt; 0.05). BL, ˙VO2 and HR in 10 × 200-m were similar to sMLSS and no different between groups. Conclusion: Intermittent swimming at CS presents physiological responses similar to sMLSS. Metabolic responses of continuous swimming at CS may not correspond to MLSS in some children and adolescent swimmers. © 2019 by the authors. Licensee MDPI, Basel, Switzerland

Analysis of selected kinematic and physiological performance determinants during incremental testing in elite swimmers

This study examined the relationships between selected kinematic and physiological parameters and their influence on performance during incremental exercise in elite swimmers competing at the international level. Eleven men and ten women (all specialized in 200-m events) performed an incremental 7 × 200-m test in their specialized stroke. Stroke rate (SR), stroke length (SL), velocity (V), and blood lactate concentration (BLa) were measured for each 200 m. In addition to the cross-sectional group design, the longitudinal performance of a male swimmer was evaluated by 4 tests during a period of 20 weeks. Stroke rate increased and SL decreased with V, regardless of the age, stroke, or gender of the swimmer. Statistically significant correlations were found between SR and V (p &lt; 0.01; r= 0.66 to 0.99), SR and SL (p &lt; 0.01; r= -0.78 to -0.99), SL and V (except for women&apos;s freestyle and breaststroke) (p &lt; 0.01; r= -0.67 to -0.98), and BLa and V (p &lt; 0.01; r = 0.7 to 0.96). Changes in SR and SL were not affected by changes in BLa. Similar velocities were produced with different combinations of SR and SL. The fastest times reached in the test were generally slower than expected, and the performance in the test was not associated with competition performance. The case study revealed similar results to those of the group. The test used in this study was informative with respect to identifying the most economical and effective stroke kinematics combination for slow to submaximal velocities. It is possible that the swimming speeds were not maximal in the final 200-m swim because of cumulative fatigue, which is a major limitation for assessing race pace. An additional test that produces velocities similar to those used in competitions would be more useful for the purpose of providing optimal kinematic information specific to racing speeds, which would facilitate performance improvement through regular monitoring in training. © 2008 National Strength and Conditioning Association

Acute effects of dynamic whole body vibration in well trained track &amp; field sprinters

Whole-body vibration is a neuromuscular training method and has been suggested as an acute ergogenic aid mode before practice, training and competition activities of athletes. The aim of this study was to investigate the acute effects of a whole-body vibration session on sprint running kinematics and neuromuscular performance in well trained track &amp; field sprinters. 30 sprint athletes participated in this study (age 21.6 ± 4.1 years, height 1.76 ± 5.0 m, body mass 71.2 ± 6.4 kg). Both experimental (with vibration) and control (without vibration) groups performed a single session of whole-body vibration consisted of two dynamic exercises (half squat / lunge) using a body vibration platform (90 s, 50 Ηz, 2 mm). Performance tests (60m sprint, counter movement jump, muscle power and sit &amp; reach test) were performed before and after 6 min the whole-body vibration session. Counter movement jump was reduced after whole-body vibration by 3.9%, whereas all the other analyzed parameters remained unchanged. The results of this study do not support the use of whole-body vibration as an acute ergogenic aid during standardized warm-up in well trained track and field sprinters. © JPES

Energy expenditure during a Vinyasa yoga session

BACKGROUND: Vinyasa yoga has been recently promoted as one of the most popular mindful exercises to improve overall health, including body weight management. The purpose of this study was to determine the metabolic response of 24 moderately trained individuals during a 90-min group Vinyasa yoga routine. METHODS: Heart rate (HR) time course of 12 males and 12 females (age: 39±7.33 years) was recorded during two group Vinyasa yoga sessions consisted of four sections (warm-up, high-intensity Surya Namaskar (HSN), no Surya Namaskar postures, and cool-down). Maximal oxygen uptake (V.O2peak) and maximum HR had been estimated earlier after a maximal treadmill test. V.O2during Vinyasa yoga sessions was estimated from individual regression equations using the relationship of and HR values derived from V.O2peak test, while the metabolic rate (kcal/min) was calculated from the relationship of HR and kcal/min. Total session energy consumption was the average value of the two yoga sessions. RESULTS: The 2 (gender) × 4 (sections) mixed ANOVA revealed no significant interaction between the two factors (P=0.101) for the mean metabolic rate (7.1±2.6 kcal/min). Mean metabolic rate thought was higher (P=0.015) in males compared to females at each section. Also, significant differences were found among the four Vinyasa yoga sections (P&amp;lt;0.001) in the rate of energy expenditure, with HSN presenting the highest mean values (P&amp;lt;0.05). CONCLUSIONS: It seems that systematic participation in Vinyasa yoga may effectively improve cardiorespiratory fitness and promote body weight loss, as an alternative method to traditional aerobic exercise. © 2020 Edizioni Minerva Medica. All rights reserved