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Volitional Weight-Lifting in Rats Promotes Adaptation via Performance and Muscle Morphology prior to Gains in Muscle Mass.

Rader EP, Miller GR, Chetlin RD, Wirth O, Baker BA - Environ Health Insights (2014)

Bottom Line: Exclusively following 700 g load training, forces increased by 21% whereas muscle masses remained unaltered.For soleus (SOL) and tibialis anterior (TA) muscles, 700 g load training increased muscle fiber number per unit area by ∼20% and decreased muscle fiber area by ∼20%.Additionally, number of muscle fibers per section increased by 18% for SOL muscles.

View Article: PubMed Central - PubMed

Affiliation: Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, WV, USA.

ABSTRACT
Investigation of volitional animal models of resistance training has been instrumental in our understanding of adaptive training. However, these studies have lacked reactive force measurements, a precise performance measure, and morphological analysis at a distinct phase of training - when initial strength gains precede muscle hypertrophy. Our aim was to expose rats to one month of training (70 or 700 g load) on a custom-designed weight-lifting apparatus for analysis of reactive forces and muscle morphology prior to muscle hypertrophy. Exclusively following 700 g load training, forces increased by 21% whereas muscle masses remained unaltered. For soleus (SOL) and tibialis anterior (TA) muscles, 700 g load training increased muscle fiber number per unit area by ∼20% and decreased muscle fiber area by ∼20%. Additionally, number of muscle fibers per section increased by 18% for SOL muscles. These results establish that distinct morphological alterations accompany early strength gains in a volitional animal model of load-dependent adaptive resistance training.

No MeSH data available.


Related in: MedlinePlus

Performance improved after one month of 700 g load training. The plot depicts the mean peak reactive forces for the initial and final five sessions of training with 70 and 700 g loads (N = 8 per group). Values are means ± SEM.
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f1-ehi-suppl.1-2014-001: Performance improved after one month of 700 g load training. The plot depicts the mean peak reactive forces for the initial and final five sessions of training with 70 and 700 g loads (N = 8 per group). Values are means ± SEM.

Mentions: Peak reactive force during each lift was used to assess performance. In general, greater peak reactive forces were required during 700 g load training compared with those during 70 g load training (Fig. 1). When comparing the peak reactive forces early in training with those late in training, an enhancement of 21 ± 6% was only observed for 700 g load training. Therefore, one month of training was sufficient to improve performance when exposed to a moderately heavy external load.


Volitional Weight-Lifting in Rats Promotes Adaptation via Performance and Muscle Morphology prior to Gains in Muscle Mass.

Rader EP, Miller GR, Chetlin RD, Wirth O, Baker BA - Environ Health Insights (2014)

Performance improved after one month of 700 g load training. The plot depicts the mean peak reactive forces for the initial and final five sessions of training with 70 and 700 g loads (N = 8 per group). Values are means ± SEM.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4216651&req=5

f1-ehi-suppl.1-2014-001: Performance improved after one month of 700 g load training. The plot depicts the mean peak reactive forces for the initial and final five sessions of training with 70 and 700 g loads (N = 8 per group). Values are means ± SEM.
Mentions: Peak reactive force during each lift was used to assess performance. In general, greater peak reactive forces were required during 700 g load training compared with those during 70 g load training (Fig. 1). When comparing the peak reactive forces early in training with those late in training, an enhancement of 21 ± 6% was only observed for 700 g load training. Therefore, one month of training was sufficient to improve performance when exposed to a moderately heavy external load.

Bottom Line: Exclusively following 700 g load training, forces increased by 21% whereas muscle masses remained unaltered.For soleus (SOL) and tibialis anterior (TA) muscles, 700 g load training increased muscle fiber number per unit area by ∼20% and decreased muscle fiber area by ∼20%.Additionally, number of muscle fibers per section increased by 18% for SOL muscles.

View Article: PubMed Central - PubMed

Affiliation: Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, WV, USA.

ABSTRACT
Investigation of volitional animal models of resistance training has been instrumental in our understanding of adaptive training. However, these studies have lacked reactive force measurements, a precise performance measure, and morphological analysis at a distinct phase of training - when initial strength gains precede muscle hypertrophy. Our aim was to expose rats to one month of training (70 or 700 g load) on a custom-designed weight-lifting apparatus for analysis of reactive forces and muscle morphology prior to muscle hypertrophy. Exclusively following 700 g load training, forces increased by 21% whereas muscle masses remained unaltered. For soleus (SOL) and tibialis anterior (TA) muscles, 700 g load training increased muscle fiber number per unit area by ∼20% and decreased muscle fiber area by ∼20%. Additionally, number of muscle fibers per section increased by 18% for SOL muscles. These results establish that distinct morphological alterations accompany early strength gains in a volitional animal model of load-dependent adaptive resistance training.

No MeSH data available.


Related in: MedlinePlus