Effect of training on eccentric exercise-induced muscle damage

Abstract

Eccentric muscle contractions generate delayed onset muscle soreness (DOMS), possibly as a result of the high tensions involved causing muscle damage. Muscle function, serum indicators of muscle damage, and DOMS were investigated throughout a training regimen that involved a 40-min eccentric walk down a 25% gradient on a treadmill at 6.4 km/h once a week for 8 wk. Serum creatine kinase and myoglobin concentrations were used as indicators of muscle damage, and both demonstrated a delayed increase after the exercise protocol. The muscles that contracted eccentrically exhibited low-frequency fatigue, as well as decreases in muscle fatigability and maximal voluntary contraction force, which were greatest immediately postexercise. Although the results show that training reduces DOMS, the serum muscle protein response, and muscle function impairment, the time courses of these adaptations are different. It is suggested that the function of the muscle can be impaired without apparent muscle damage.

Adaptive strength gains in dystrophic muscle exposed to repeated bouts of eccentric contraction

“…2. Maximal anterior crural muscle torques for bouts [1][2][3][4][5]. A: means Ϯ SE of peak isometric torques produced preinjury at bouts 1-5 for groups of mice with different rest intervals between bouts.…”

“…Also, SERCA1a and parvalbumin protein contents as well as the percentage of fibers with centralized nuclei were compared between in vivo-injured and contralateral control TA muscles using paired t-tests. 2 -Analysis was used to determine differences in fiber size distribution. For experiment 3, ex vivo contractile properties and total and contractile protein contents were compared between in vivo-injured and contralateral control EDL muscles using paired t-tests.…”

“…The main functional consequence of eccentric contractioninduced injury is the immediate and then sustained reduction in the muscle's ability to generate force (2,9,18). Here, we used an in vivo method to elicit eccentric contraction injury and then to assess muscle strength, allowing us to track the functional recovery over time in the same mdx mice.…”

Muscle damage occurring in wheelchair sports people

“…[1][2][3] In laboratory conditions, severe exercise involving the elbow¯exors has been commonly studied. [4][5][6][7] Delayed onset muscle soreness (DOMS) 8,9 and maximum voluntary contraction 4,6 were widely evaluated as non-invasive parameters. For invasive parameters, not many authors have used muscle biopsies and histology.…”

“…For invasive parameters, not many authors have used muscle biopsies and histology. 10 Many researchers have carried out blood sampling, measuring several parameters: 1,3,4,6,9,11 enzyme activities such as creatinekinase (CK) or lactatedehydrogenase (LDH), myoglobin (Mb) content appeared to be the most reliable parameters.…”