Serum creatine kinase activity following forearm flexion isometric exercise

Abstract

The purpose of this study was to compare serum creatine kinase (CK) activity following two forearm flexion isometric exercise regimens differing in work to rest ratio, and examine the CK response to a repeated bout of isometric exercise. Eleven males were tested on two sessions (bouts) spaced 1 week apart. For bout 1, five subjects (group A) performed a forearm flexion isometric exercise consisting of 40 10-s maximal contractions with 20-s inter-trial rests (10:20), while six (group B) performed 40 maximal 10-s contractions with 5-s inter-trial rests (10:5). The increase in serum CK activity following the 10:20 exercise (143%) was significantly greater than that following the 10:5 exercise (52%). The 10:20 exercise was also associated with greater tension generation over trials. One week later, both groups performed a bout of 10:20 exercise. A substantial reduction in the serum CK response was found following this second bout. The data suggest that for bout 1 the isometric exercise associated with the greater overall tension levels resulted in the greater CK response. However, when the 10:20 exercise was repeated 1 week later, a substantial reduction in the CK response was found which was unrelated to the tension generated.

The Effect of One Session of Muscle Soreness-Inducing Weight Lifting Exercise on WBC Count, Serum Creatine Kinase, and Plasma Volume

“…Significant increases in serum CK activity have been reported following eccentric and isometric exercise (9,10,28) and appear to be related more to intensity of exercise than duration (8,34). The large increases in CK activity exhibited in the present study were probably due to the high intensity of exercise (80 percent, 1 RM), the eccentric component of each repetition, and the involvement of most of the major muscle groups of the body.…”

Angle-specific impairment of elbow flexors strength after isometric exercise at long muscle length

“…T o the authors' knowledge, this is the first study to report an angle-specific decrease in and recovery of MIF after isometric exercise. The isometric exercise protocol used caused significantly more muscle damage than the protocols reported in previous studies (Clarkson et al, 1985;Jones et al, 1989;Nosaka et al, 2002). This can be assessed not only by the magnitude of decrease in MIF, which was more than double that reported in previous studies (e.g.…”

“…This can be assessed not only by the magnitude of decrease in MIF, which was more than double that reported in previous studies (e.g. Jones et al, 1989), but also by increases in indirect markers of muscle damage, such as creatine kinase and relaxed elbow angle, which were several-fold higher compared with other isometric exercise protocols (Clarkson et al, 1985(Clarkson et al, , 1986(Clarkson et al, , 1987Nosaka et al, 2002). This may have been due to the protocol used in the present study, which involved 50 maximal contractions of 10 s with 20 s rest between contractions, with the elbow flexors stretched to a lengthened position.…”

“…Each muscle action was performed for 10 s, with 20 s of intervening rest. A similar exercise regimen has previously been shown to result in an increase in serum creatine kinase activity, which is indirect evidence of muscle damage (Clarkson et al, 1985(Clarkson et al, , 1987.…”

“…Therefore, the present study was designed to provide a more complete picture of muscle function impairment after a modified protocol of repeated maximal isometric contractions of the elbow flexors at a long muscle length (Clarkson et al, 1985;Jones et al, 1989). More specifically, the following hypotheses were tested: (I) repeated maximal isometric contractions at long muscle length cause long-term decreases (96 h) of force-generating capacity due to muscle damage, and (2) the decreases in forcegenerating capacity are dependent on muscle lengththat is, the reduction in MIF after exercise at long muscle length will be more pronounced at short muscle lengths.…”