Power output of the lower limb during variable inertial loading: a comparison between methods using single and repeated contractions

The power–inertial load relationship of the lower limb muscles was studied during a single leg thrust using the Modified Nottingham Power Rig (mNPR) and during cycling exercise in nine young male subjects. The relationship between peak power and inertial load showed a parabolic-like relationship for mNPR exertions, with a peak [937 (SD 246) W] at 0.158 kg m2, this being significantly (P <0.05) different from the power generated at both the lowest [723 (162) W] and highest [756 (206) W] inertial loads. In contrast, for cycling exercise power output did not differ significantly between inertial loads, except at the lowest inertia where power output was significantly (P<0.05) less compared with all other inertial loads. Maximum peak power output during cycling was 1,620 (336) W, which was significantly (P <0.05) greater than that recorded on the mNPR. However, a close association was observed between the mean power generated by each method (r=0.84, P<0.05). The results suggest that during a single contraction a range of inertial loads is required to allow peak power to be expressed. Above a certain critical value, this is unnecessary during cycling movements where the load can be repeatedly accelerated.

[1]  G. Grimby,et al.  Use of a Kin-Com dynamometer to study the stretch-shortening cycle during plantar flexion , 2004, European Journal of Applied Physiology and Occupational Physiology.

[2]  E F Coyle,et al.  Time course of learning to produce maximum cycling power. , 2000, International journal of sports medicine.

[3]  J. Bangsbo,et al.  Moment and power generation during maximal knee extensions performed at low and high speeds , 2004, European Journal of Applied Physiology and Occupational Physiology.

[4]  C. Davies,et al.  Effect of temperature on the contractile properties and muscle power of triceps surae in humans. , 1983, Journal of applied physiology: respiratory, environmental and exercise physiology.

[5]  A. Sargeant,et al.  Maximum leg force and power output during short-term dynamic exercise. , 1981, Journal of applied physiology: respiratory, environmental and exercise physiology.

[6]  J Baker,et al.  Power output of legs during high intensity cycle ergometry: influence of hand grip. , 2000, Journal of science and medicine in sport.

[7]  H. Vandewalle,et al.  Torque-velocity relationship during cycle ergometer sprints with and without toe clips , 1997, European Journal of Applied Physiology and Occupational Physiology.

[8]  A. V. van Soest,et al.  Why is countermovement jump height greater than squat jump height? , 1996, Medicine and science in sports and exercise.

[9]  A. Sargeant.  Effect of muscle temperature on leg extension force and short-term power output in humans , 2004, European Journal of Applied Physiology and Occupational Physiology.

[10]  M. Hull,et al.  A method for determining lower extremity muscle-tendon lengths during flexion/extension movements. , 1990, Journal of biomechanics.

[11]  P. Cavanagh,et al.  The physiology and biomechanics of cycling , 1978 .

[12]  E. Coyle,et al.  Inertial-load method determines maximal cycling power in a single exercise bout. , 1997, Medicine and science in sports and exercise.

[13]  D. Grieve,et al.  A variable inertial system for measuring the contractile properties of human muscle. , 2001, Medicine and science in sports and exercise.

[14]  N L Jones,et al.  Power output and fatigue of human muscle in maximal cycling exercise. , 1983, Journal of applied physiology: respiratory, environmental and exercise physiology.

[15]  R. Baron,et al.  Measurement of maximal power output in isokinetic and non-isokinetic cycling. A comparison of two methods. , 1999, International journal of sports medicine.

[16]  E. Bassey,et al.  A new method for measuring power output in a single leg extension: feasibility, reliability and validity , 2004, European Journal of Applied Physiology and Occupational Physiology.