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

Changes in leg strength and kinematics with uphill - downhill sprint training

This study examined the effects of an 8-week uphill-downhill sprint training programme on the force generation capacity of leg muscles. Twenty-four university students were randomly allocated to one of two training groups (combined uphill–downhill and horizontal) and a control group. The combined training method produced significant improvements in maximal isometric force (7.1%) and rate of force production (≈ 25%) of the knee flexor muscles (p<0.05). The combined training was also significantly more effective in improving the maximum sprinting speed (5.9%, p<0.05) and associated kinematic variables. In particular, the propulsive phase of contact decreased significantly by 17% (p<0.05) indicating a link between the improved rate of force production during the isometric test and the rate of production of propulsive forces during sprinting. The increased capacity of the leg flexor muscles to generate force appears to contribute to the improvement of sprinting speed perhaps due to a more efficient muscle function during the support phase of the stride

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 &plusmn; 0.4 years) and ten adolescents (15.8 &plusmn; 0.7 years). Blood lactate concentration (BL), oxygen uptake ( V &middot; O2), and heart rate (HR) at sMLSS were compared to intermittent (10 &times; 200-m) and continuous swimming corresponding to CS. Results: CS was similar to sMLSS in children (1.092 &plusmn; 0.071 vs. 1.083 &plusmn; 0.065 m&middot;s&minus;1; p = 0.12) and adolescents (1.315 &plusmn; 0.068 vs. 1.297 &plusmn; 0.056 m&middot;s&minus;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 &plusmn; 1.8, sMLSS: 3.4 &plusmn; 1.5; adolescents: CS: 4.5 &plusmn; 2.3, sMLSS: 3.1 &plusmn; 0.8 mmol&middot;L&minus;1; p &lt; 0.05). V &middot; O2 and HR in continuous swimming at CS were not different compared to sMLSS (p &gt; 0.05). BL, V &middot; O2 and HR in 10 &times; 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