Mercer, Tom and Gleeson, Nigel and Claridge, S. and Clement, S. (1998) Prolonged intermittent high intensity exercise impairs neuromuscular performance of the knee flexors. European Journal of Applied Physiology, 77 (6). pp. 560-562. ISSN 1439-6319
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Official URL: http://dx.doi.org/10.1007/s004210050377
This study investigated the effect of prolonged intermittent high intensity exercise upon the isokinetic leg strength and electromechanical delay of the knee flexors. Seven male collegiate soccer players were exposed to: (i) a prolonged intermittent high intensity exercise task (PIHIET) which required subjects to complete a single-leg pedalling task, with the preferred limb, (75 rpm for all constant-load portions of the task) consisting of 48 × 1.8 minute cycles of exercise, and (ii) a control task consisting of no exercise. Pre-, mid- and post-PIHIET gravity corrected indices of knee flexion angle-specific torque (0.44 rad knee flexion (AST); 0 rad = full knee extension; [1.05 rad · s−1]) were made for both intervention and control limbs. Electromechanical delay (EMD) of the m. biceps femoris during supine knee flexion movements was evaluated in the preferred leg on both intervention and control days. Repeated measures ANOVAs revealed significant condition (intervention; control) by time (pre; mid; post) interactions for both knee flexor AST (F[2,12] = 4.8; p<0.03) and EMD (F[2,12] = 4.1; p<0.05). AST was observed to decrease by 16% and EMD increase by 30% pre to post intervention. These observations suggest an impairment of neuromuscular control and the ability to maintain force generation in the knee flexors, near the extremes of the range of motion during prolonged intermittent high-intensity exercise activities. Changes of this magnitude may pose a threat to the integrity of the knee joint.
|Uncontrolled Keywords:||Fatigue - Strength - Isokinetic - Electromechanical Delay - Males|
|Deposited On:||11 Dec 2009 12:45|
|Last Modified:||22 Nov 2012 14:43|
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