Table 2.

Mechanical outputs at the beginning and end of the fatiguing dynamic exercise

		Young (n= 7)	Old (n= 8)	P value
Power
Beginning	(W)	77.2 ± 30.6	41.0 ± 12.1	0.015
End	(W)	42.6 ± 20.4	9.7 ± 5.2	0.001
Force
Beginning	(N)	127.9 ± 31.3	89.6 ± 17.0	0.028
End	(N)	99.0 ± 22.3	64.6 ± 10.6	0.002
Velocity
Beginning	(m s−1)	0.60 ± 0.16	0.45 ± 0.08	0.040
End	(m s−1)	0.41 ± 0.12	0.15 ± 0.06	<0.001
Displacement
Beginning	(cm)	21.1 ± 4.7	17.9 ± 2.7	0.130
End	(cm)	17.5 ± 3.6	11.1 ± 2.1	0.001

Power, force and velocity are the average values calculated over the entire shortening phase of the knee extension movement cycle. Because power output increased over the first few contractions in some participants, the recorded baseline mechanical outputs for each participant are the highest average obtained from 10 sequential contractions within the first 20 contractions at the beginning of the dynamic exercise. The reported mechanical outputs from the end of the fatiguing dynamic exercise are the average values from the last 10 contractions. A significant age difference at P < 0.05 is indicated in bold. Values are the mean ± SD.