Michael Ro
Mon, Aug-12-02, 20:02
The following research confirms that prolonged running
decreases strength of the leg muscles directly after a running
session (big surprise!).
It does not examine the possible existence of any long term
after-effects. At least the moral here is don't plan on doing
any serious lifting training straight after a 2 hour run, as
if we didn't already know that!
The most interesting aspect of this work is that eccentric
strength is especially diminished.
--------------------
Int J Sports Med 2000 May; 21(4):275-80
The effects of a prolonged running exercise on strength
characteristics
Lepers R, Pousson ML, Maffiuletti NA, Martin A, Van Hoecke J
The aim of this study was to examine concentric, isometric,
and eccentric strength reductions in the quadriceps muscle
following a prolonged running exercise. Before and after a 2 h
run (28.4±1.4 km) peak torque (PT) of the knee extensors at
angular velocities of -120, -90, -60, 0, 60, 120, 180, 240
degrees x s(-1) using an isokinetic dynamometer,
electromyographic (EMG) activity of the vastus lateralis
(VL) and vastus medialis (VM) muscles and height of a counter
movement jump were recorded in twelve well-trained
triathletes.
Counter movement jump performances decreased by 10% and PT
values were all significantly lower at each angular velocity
following the run. The torque loss was significantly greater
under eccentric contractions (from 18 to 21%) than under
concentric ones (from 11 to 14%). EMG activity (RMS) was lower
in both VL and VM muscles after the 2 h run but no difference
existed in RMS losses between concentric and eccentric
contractions.
The present results demonstrate that:
1. a prolonged running exercise more greatly affects eccentric
force production in the quadriceps muscle, and
2. this specificity seems to be due to an impairment of the
muscular contractile mechanism rather than a modification
to the neural input.
decreases strength of the leg muscles directly after a running
session (big surprise!).
It does not examine the possible existence of any long term
after-effects. At least the moral here is don't plan on doing
any serious lifting training straight after a 2 hour run, as
if we didn't already know that!
The most interesting aspect of this work is that eccentric
strength is especially diminished.
--------------------
Int J Sports Med 2000 May; 21(4):275-80
The effects of a prolonged running exercise on strength
characteristics
Lepers R, Pousson ML, Maffiuletti NA, Martin A, Van Hoecke J
The aim of this study was to examine concentric, isometric,
and eccentric strength reductions in the quadriceps muscle
following a prolonged running exercise. Before and after a 2 h
run (28.4±1.4 km) peak torque (PT) of the knee extensors at
angular velocities of -120, -90, -60, 0, 60, 120, 180, 240
degrees x s(-1) using an isokinetic dynamometer,
electromyographic (EMG) activity of the vastus lateralis
(VL) and vastus medialis (VM) muscles and height of a counter
movement jump were recorded in twelve well-trained
triathletes.
Counter movement jump performances decreased by 10% and PT
values were all significantly lower at each angular velocity
following the run. The torque loss was significantly greater
under eccentric contractions (from 18 to 21%) than under
concentric ones (from 11 to 14%). EMG activity (RMS) was lower
in both VL and VM muscles after the 2 h run but no difference
existed in RMS losses between concentric and eccentric
contractions.
The present results demonstrate that:
1. a prolonged running exercise more greatly affects eccentric
force production in the quadriceps muscle, and
2. this specificity seems to be due to an impairment of the
muscular contractile mechanism rather than a modification
to the neural input.