Optimal resistance for maximal power during treadmill running*

Sprint running performance: comparison between treadmill and field conditions

“…the motor torque necessary to overcome the friction on the belt due to subject's body weight. The default torque was measured by requiring the subject to stand still at the centre of the treadmill and by increasing the driving torque value until observing a movement of the belt greater than 2 cm over 5 s. This default torque setting as a function of belt friction is in line with previous motorized treadmill studies (Chelly and Denis 2001;Falk et al 1996;Jaskolski et al 1996;Jaskoska et al 1999) and with the detailed discussion by McKenna and Riches in their recent study comparing ''torque treadmill'' sprint to overground sprint (McKenna and Riches 2007). The motor torque of 160% of the default value was selected after several preliminary measurements (data not shown) comparing various torques, because (a) it allowed subjects to sprint in a comfortable manner and produce their maximal effort without risking loss of balance, and (b) higher torques (180 and 200%) caused loss of balance in some of the subjects.…”

Direct measurement of power during one single sprint on treadmill

“…This allowed us to set, for each subject, the default motor torque that was necessary to overcome the friction on the belt due to subject's body weight. This was done by requiring the subject to stand still and by increasing the driving torque value until observing a movement of the belt greater than 2 cm over 5 s. This default torque setting as a function of belt friction is in line with previous motorized-treadmill studies (Chelly and Denis, 2001;Falk et al, 1996;Jaskolska et al, 1999a,b;Jaskolski et al, 1996), and with the detailed discussion by McKenna and Riches in their recent study comparing ''torque treadmill'' sprint to overground sprint (McKenna and Riches, 2007). From this value of default load, we determined individual values of higher resistance (20% lower motor torque) and lower resistance (20% higher motor torque).…”

“…Power output is then measured as the product of the treadmill belt velocity and the horizontal component of the force exerted on the tether, measured by force transducers and goniometers. These treadmills are either non-motorized (Belli and Lacour, 1989;Cheetham et al, 1985;Funato et al, 2001;Lakomy, 1987;Nevill et al, 1989) or motorized (Chelly and Denis, 2001;Falk et al, 1996;Jaskolska et al, 1999b;Jaskolski et al, 1996) and in this case, the default motor torque is set to compensate for the friction of the treadmill belt-bed due to subjects' body weight.…”

“…Propulsive power is thus the product of the horizontal component of force and velocity, though these two entities are not applied/measured at the same location (the end of the tether and the ground, respectively). Further, an additional torque is needed to compensate the friction due to subjects' weight on the belt and allow them to reach maximal running velocities close to free running ones (Chelly and Denis, 2001;Falk et al, 1996;Jaskolska et al, 1999b;Jaskolski et al, 1996;McKenna and Riches, 2007).…”

A simple method for measuring force, velocity and power output during squat jump

“…Further, testing the maximal power output of lower limbs extensor muscles is a common practice in the assessment of human exercise performance. Maximal power output has been assessed from different leg movements, namely sprint running (Jaskolska et al, 1999;Jaskolski et al, 1996), sprint pedalling (Arsac et al, 1996;Seck et al, 1995;Vandewalle et al, 1987a) or vertical jumping (Davies and Young, 1984;Rahmani et al, 2000;Wilson et al, 1997). No matter what the type of leg movement analysed, power output may be computed as the product of force times velocity.…”