TY - JOUR
T1 - Influence of muscle hypertrophy on the moment arm of the triceps brachii muscle
AU - Sugisaki, Norihide
AU - Wakahara, Taku
AU - Murata, Koichiro
AU - Miyamoto, Naokazu
AU - Kawakami, Yasuo
AU - Kanehisa, Hiroaki
AU - Fukunaga, Tetsuo
PY - 2015/4/1
Y1 - 2015/4/1
N2 - Although the moment arm of the triceps brachii muscle has been shown to be associated with the muscle's anatomical cross-sectional area, whether training-induced muscle hypertrophy alters the moment arm of the muscle remains unexplored. Therefore, the current study aimed to examine this. Eleven men underwent a 12-week resistance training program for the triceps brachii muscle. The maximum muscle anatomical cross-sectional area (ACSAmax), the moment arm of the triceps brachii muscle, and the anterior-posterior dimension of the olecranon were measured using a magnetic resonance imaging system before and after intervention. The ACSAmax (33.6 ± 11.9%, P < .001) and moment arm (5.5 ± 4.0%, P = .001) significantly increased after training, whereas the anterior-posterior dimension of the olecranon did not change (P > .05). The change in moment arm was smaller than that expected from the relationship between the ACSAmax and the moment arm before the intervention. The present results indicate that training-induced triceps brachii muscle hypertrophy could increase the muscle moment arm, but its impact can be small or negligible.
AB - Although the moment arm of the triceps brachii muscle has been shown to be associated with the muscle's anatomical cross-sectional area, whether training-induced muscle hypertrophy alters the moment arm of the muscle remains unexplored. Therefore, the current study aimed to examine this. Eleven men underwent a 12-week resistance training program for the triceps brachii muscle. The maximum muscle anatomical cross-sectional area (ACSAmax), the moment arm of the triceps brachii muscle, and the anterior-posterior dimension of the olecranon were measured using a magnetic resonance imaging system before and after intervention. The ACSAmax (33.6 ± 11.9%, P < .001) and moment arm (5.5 ± 4.0%, P = .001) significantly increased after training, whereas the anterior-posterior dimension of the olecranon did not change (P > .05). The change in moment arm was smaller than that expected from the relationship between the ACSAmax and the moment arm before the intervention. The present results indicate that training-induced triceps brachii muscle hypertrophy could increase the muscle moment arm, but its impact can be small or negligible.
KW - Elbow
KW - MRI
KW - Muscle cross-sectional area
KW - Resistance training
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U2 - 10.1123/JAB.2014-0126
DO - 10.1123/JAB.2014-0126
M3 - Article
C2 - 25411895
AN - SCOPUS:84928604859
VL - 31
SP - 111
EP - 116
JO - Journal of Applied Biomechanics
JF - Journal of Applied Biomechanics
SN - 1065-8483
IS - 2
ER -