Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE credits
ABSTRACT
INTRODUCTION The demographics show a significant increase in the older population
(60+) in the next decades. Aging involves physio-pathological changes in the body and
movement system. However, training seems to be a promising strategy to counteract
aging symptoms. The purpose of this thesis is to study skeletal muscle hypertrophy and
fiber type composition in young and old men participating in a six-week progressive
resistance exercise program. The second aim is to investigate the effect of long-term
participation in group-organized resistance and endurance training on body composition
in old women.
MATERIAL AND METHODS 10 healthy young (~23y) and 10 healthy old (~69y) men
underwent a 6-week progressive resistance training (75% of 1 repetition maximum).
Immunohistochemistry was used to stain for myosin heavy chain I and IIa, laminin,
satellite cells and myonuclei. Fiber cross-sectional area was measured to evaluate
skeletal muscle hypertrophy. Bioelectrical Impedance analysis was used to estimate
body composition on 33 healthy old women (~69y). A questionnaire about the subjects’
training habits was used to categorize them into 3 groups.
RESULTS We found a significant increase in fiber CSA in type IIa fibers and satellite
cell content in type I fibers after 6 weeks in old men only. Myonuclear content was
increased in both young and old after 3 and 6 weeks of progressive resistance training.
A fiber type shift from type IIa to IIx fibers was seen after 6 weeks in old men only. No
differences were found in BMI, skeletal muscle and fat mass, body fat percentage,
skeletal muscle index and phase angle between the three groups of older women.
Skeletal muscle index showed that the subjects of all groups have no sarcopenia.
Phase angle did not differ from younger populations.
CONCLUSION 6-week progressive resistance training program leads to hypertrophy
and fiber type shift in old men. The Activity level may not affect body composition in
elderly women. However, the groups might have not differed enough to see differences.
2017.