How do some exercisers get away with less soreness than others?
A new study suggests flexibility reduces susceptibility to exercise-induced muscle damage and delayed-onset muscle soreness (DOMS).
Eccentric exercise frequently causes muscle damage and DOMS. To induce muscle damage, subjects performed six sets of 10 isokinetic eccentric hamstring contractions at 60 percent of maximum strength, so everyone exercised at the same relative intensity.
On the following three days, subjects were tested for DOMS symptoms.
The least flexible subjects (as measured by passive stiffness) felt significantly more muscle tenderness and pain than the most flexible subjects on the second and third days.
The least flexible subjects also experienced a statistically significant loss of isometric strength, and increased creatine kinase activity (another indicator of muscle damage).
Researchers theorize that the strain of lengthening stiff muscles during eccentric contraction results in muscle fiber damage.
''Exercise in the presence of muscle damage involves a greater metabolic stress, and limits exercise intensity and duration.
Therefore, more flexible people may be able to exercise at a higher intensity or for a greater duration on the days after a bout of eccentric exercise,'' they conclude.
Source: The American Journal of Sports Medicine, 1999; 27, 5: 594-599