TY - JOUR

T1 - Effect of elbow joint angle on the magnitude of muscle damage to the elbow flexors

AU - Nosaka, Kazunori

AU - Sakamoto, Kei

PY - 2001/1/1

Y1 - 2001/1/1

N2 - Purpose: It has been shown that eccentric actions at a long muscle length result in a larger decrease in force and more muscle tenderness compared with those at a short muscle length. To further investigate the effect of elbow joint angle on the development of muscle damage, this study compared two maximal eccentric exercise regimens in which the starting position of the action was different, but the range of movement was the same. Methods: One arm of 10 male students performed 24 maximal eccentric actions of the elbow flexors at the elbow joint angle from 0.87 to 2.27 rad (50-130°: S condition) and the other arm at the elbow joint angle from 1.74 to 3.14 rad (100-180°: L condition). Maximal isometric force, range of motion, muscle soreness, plasma creatine kinase activity, upper arm circumference, and B-mode ultrasound pictures of the elbow flexors (US) were measured before and for 5 d postexercise in both conditions. Magnetic resonance imaging (MRI) of the transverse scans of the upper arm was taken at 4 d after exercise. Results: All measures changed significantly (P < 0.01) after exercise for both conditions; however, significantly (P < 0.01) larger changes in the measures were found in the L condition compared with the S condition. MRI and US displayed that only the brachialis was damaged for the S condition but the biceps brachii was also damaged for the L condition. Conclusion: The greater development of muscle damage in the L condition compared with the S condition is likely to be associated with the elbow flexors muscles affected by the exercise.

AB - Purpose: It has been shown that eccentric actions at a long muscle length result in a larger decrease in force and more muscle tenderness compared with those at a short muscle length. To further investigate the effect of elbow joint angle on the development of muscle damage, this study compared two maximal eccentric exercise regimens in which the starting position of the action was different, but the range of movement was the same. Methods: One arm of 10 male students performed 24 maximal eccentric actions of the elbow flexors at the elbow joint angle from 0.87 to 2.27 rad (50-130°: S condition) and the other arm at the elbow joint angle from 1.74 to 3.14 rad (100-180°: L condition). Maximal isometric force, range of motion, muscle soreness, plasma creatine kinase activity, upper arm circumference, and B-mode ultrasound pictures of the elbow flexors (US) were measured before and for 5 d postexercise in both conditions. Magnetic resonance imaging (MRI) of the transverse scans of the upper arm was taken at 4 d after exercise. Results: All measures changed significantly (P < 0.01) after exercise for both conditions; however, significantly (P < 0.01) larger changes in the measures were found in the L condition compared with the S condition. MRI and US displayed that only the brachialis was damaged for the S condition but the biceps brachii was also damaged for the L condition. Conclusion: The greater development of muscle damage in the L condition compared with the S condition is likely to be associated with the elbow flexors muscles affected by the exercise.

KW - Eccentric exercise

KW - Isometric force

KW - MRI

KW - Muscle soreness

KW - Plasma creatine kinase activity

UR - http://www.scopus.com/inward/record.url?scp=0035154950&partnerID=8YFLogxK

U2 - 10.1097/00005768-200101000-00005

DO - 10.1097/00005768-200101000-00005

M3 - Journal article

C2 - 11194107

AN - SCOPUS:0035154950

VL - 33

SP - 22

EP - 29

JO - Medicine and Science in Sports and Exercise

JF - Medicine and Science in Sports and Exercise

SN - 0195-9131

IS - 1

ER -