Is isometric strength loss immediately after eccentric exercise related to changes in indirect markers of muscle damage?

Abstract

This study tested the hypothesis that the magnitude of maximal isometric strength (MVC) loss immediately following eccentric exercise (MVC-post) would relate to changes in other indirect markers of muscle damage following exercise. Eighty-nine men were recruited from the same student population and performed 24 maximal eccentric actions of the elbow flexors. Commonly used markers of muscle damage such as relaxed and flexed elbow joint angles, range of motion (ROM), upper-arm circumference, muscle soreness, and plasma creatine kinase (CK) activity were measured before, immediately after, and 1-4 d after exercise. Pearson's product-moment correlation coefficients (r) between change in MVC-post and other markers of muscle damage, as well as MVC during recovery days, were calculated. Changes in MVC-post ranged from -72.8% to -17.6%, and correlated significantly (p < 0.01) with MVC at 1 (r = 0.59), 2 (0.63), 3 (0.61), and 4 (0.62) d after exercise. Reduction in MVC-post also correlated significantly (p < 0.05) with changes in relaxed (r = 0.50) and flexed elbow joint angles (-0.40), ROM (0.55), arm circumference (-0.45), peak palpation (-0.34) and extension muscle soreness (-0.48), and peak CK activity (-0.59). However, the r values were not necessarily high, and MVC-post poorly reflected the distribution of some measures, such as peak CK activity (124 - 50 440 IU x L(-1). These results suggest that MVC-post is not a strong correlate of the changes in markers of muscle damage following eccentric exercise of the elbow flexors.

Work And Peak Torque During Eccentric Exercise Do Not Predict Changes In Markers Of Muscle Damage

“…The performance of 60 eccentric actions of the elbow flexors at 90° s −1 resulted in significant decrements in isometric strength and ROM, elevated levels of palpated muscle soreness and significant increases in plasma CK activity 4 days post-exercise (fig 4A−D). The extent of subject variability recorded following isokinetic exercise is similar to the variability previously described following manually controlled eccentric exercise 14. Measures of work performed during exercise (Total work, Wk/MVC and %Δ Wk) demonstrated a significant correlation with many of the variables including ROM and SOR; however, the correlations were not strong (table 1).…”

Muscle fatigue experienced during maximal eccentric exercise is predictive of the plasma creatine kinase (CK) response

“…As the MR images provide a more complete evaluation of the extent of muscle damage compared with damage assessed from a biopsy sample, the authors suggested that the large variability in CK response is related to the variability in EIMD. In contrast, other studies (Nosaka et al, 2006;Skurvydas et al, 2011) demonstrated that reduction in strength loss poorly reflected the distribution of some measures, such as peak CK activity. In addition, it is worth noting that for the first time, the present study transformed the CK data as logarithm, allowing a linear correlation to be apparent.…”

“…We observed that subjects assigned in the HR group were those experiencing the largest absolute and relative work decrease during the eccentric exercise. The relationship between CK activity and muscle force loss immediately post‐exercise has already been investigated many times in humans (Clarkson et al., ; Nosaka & Clarkson, ; Nosaka et al., ; Skurvydas et al., ), but the findings remained equivocal and none of these studies tested the relationship between CK and the modifications of the work parameter during the exercise instead of strength loss post‐exercise. For example, Nosaka and Clarkson () previously demonstrated significant correlations of peak CK levels after isokinetic eccentric protocol with muscle strength loss post‐exercise and abnormality in magnetic resonance (MR) images.…”

Rate of force development as a measure of muscle damage

“…Although histological alterations provide a direct evidence of muscle damage, eccentric exercise-induced muscle damage is often assessed indirectly by increases in muscle proteins in the blood (e.g., creatine kinase: CK), ratings of delayed onset muscle soreness, and decreases in muscle strength and range of motion (Nosaka & Clarkson, 1995;Chen et al, 2010Chen et al, , 2011. Among these, a prolonged decrease in maximum voluntary contraction (MVC) peak force or torque has been considered to be the best indirect measure of eccentric exercise-induced muscle damage (Warren et al, 1999;Nosaka et al, 2006). Large decreases in MVC peak force (30-50%) are evident for several days following maximal eccentric elbow flexor exercise, together with abnormalities shown by ultrasound and/or magnetic resonance imaging (Nosaka & Clarkson, 1996) and myofibril necrosis (Jones et al, 1986;Mackey et al, 2011).…”