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JOURNAL
OF
SPORTS SCIENCE &
MEDICINE
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Research
article
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MUSCLE STRENGTH AND DAMAGE FOLLOWING TWO MODES OF VARIABLE RESISTANCE TRAINING |
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Saied Jalal Aboodarda1  ,
John George2, Abdul Halim Mokhtar3 and Martin Thompson4 |
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1Sports Center, 2Department of Biomedical Imaging, and 3Sports Medicine Unit, Faculty of Medicine, University of Malaya, Malaysia, 4Faculty of Health Sciences, Discipline of Exercise & Sport Science, The University of Sydney, Australia |
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© Journal of Sports Science and Medicine (2011) 10, 635 - 642 |
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| ABSTRACT | |||
| Nautilus Machine (NM) and Elastic Resistance (ER) have gained
considerable popularity among athletes and recreational lifters seeking
to increase muscle strength. However, there is controversy concerning the
use of ER for increasing muscle hypertrophy and strength among healthy-trained
individuals. The aim of the study was to compare the effect of repeated
near maximal contractions by ER/NM on indicators of muscle damage including:
maximal strength decrement (MVIC), rate of muscle soreness (DOMS), concentration
of plasma creatine kinase (CK) and increased high muscle signal on T2 weighted
images using magnetic resonance imaging (MRI). Nine healthy male subjects
completed two modalities of exercise (5 sets × 10RM ER/NM) in a counterbalance
cross-over study design with three weeks "wash-out" period between
experiments. The MVIC was measured and DOMS rated and recorded for 4 consecutive
days while blood samples were collected on day 1, 3, 5 and 7. Prior to and
forty eight hours after completion of each mode of exercise, subjects underwent
MRI scanning. The average of applied forces demonstrated significantly higher
value for NM compared with ER (362 ± 34.2 N vs 266.73 ± 44.6 N respectively)
throughout the 5 sets of dynamic exercise (all p < 0.05). However, the
indicators of muscle damage (T2 relaxation time, DOMS, MVIC and serum CK)
exhibited a very similar response across both modes of training. Plasma
CK increased significantly following both modes of training with the peak
value on Day 3 (p < 0.05). The time course of muscle soreness reached
a significant level after both modes of exercise and showed a peak value
on the 2nd day (p < 0.05). The T2 relaxation time demonstrated a statistically
significant increase following ER and NM compared with the pre-test value
(p < 0.05). The similarity of these responses following both the ER and
NM exercise training session suggests that both modes of training provide
a similar training stress; despite a considerably lower external force generation
during ER. The importance of these findings is underlined by the fact that
exercise-induced muscle damage has been shown to be the underlying mechanism
of further muscle hypertrophy. Key words: Elastic resistance training, magnetic resonance imaging, muscle strain, muscle hypertrophy. |
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