THE EFFECTS OF STRENGTH TRAINING ON SARCOPENIA

The following are excerpts from The Canadian Journal of Applied Physiology regarding the potential effects of High Intensity Resistance Training (H.I.R.T.) on age related muscle loss. 

In contrast to the results for whole body muscle mass, measurements of specific muscle groups’ cross-sectional area (CSA) or volume have been much more consistent...almost all studies have seen site specific muscle hypertrophy.
— Michelle M. Porter
Muscle fiber hypertrophy has been investigated and positive results have been seen as a result of even short-term resistance training (8 or 9 weeks, see table 3)
— Michelle M. Porter
Other data on myosin expression comes from the work of Fiatarone Singh and colleagues (1999) who have shown that neonatal myosin heavy chain expression increased 2.5 times in very old, frail subjects in response to 10 weeks of resistance training. The authors suggested that this could indicate “hypertrophy of mature fibers, or activation of either new myogenic precursor cells or severely atrophied fibers”
— Michelle M. Porter
No changes have been found in whole body protein synthesis as assessed by leucine kinetics following resistance training in older adults...Increases in Vastus Lateralis protein synthesis have also been reported in relatively younger, (65-72 years) older adults, ranging from 30% - 155%
— Michelle M. Porter
The evidence is certainly available that strength training in older adults results in increased protein synthesis and hypertrophy that is measurable at the muscle fiber, whole muscle, and whole body levels. This effect is still possible in frail nursing home residents in their 90’s.
— Michelle M. Porter
Typically, though, the strength increments associated with high intensity resistance training have been much larger than the hypertrophic response, leading to the conclusion that most of the adaptation to strength training is neural.
— Michelle M. Porter
Presumably, if functional performance, metabolic rate, and ultimately health outcomes are desired, then this training should continue over the long term in older adults to lessen the effects of sarcopenia.
— Michelle M. Porter
With aging the decline in strength and muscle mass is accompanied by a slowing of contraction, which may be due to a predominant reduction of Type 2 muscle tissue or other changes in the muscles such as calcium or cross-bridge kinetics.
— Michelle M. Porter
For these short-term studies, though, it is clear that protein synthesis, whole body muscle mass, specific muscle CSA or volume, and muscle fiber size increases occur with resistance training.
— Michelle M. Porter
Although hypertrophy is evident, strength increases usually always surpass the whole body, whole muscle, or muscle fiber size enhancements with training. This points to the neural adaptations that also occur with resistance training. At present it is clear that strength training 2 - 3 days per week will lead to strength and muscle mass increases...for older adults and in particular frail older adults who stand to gain the most.
— Michelle M. Porter
Aaron TanasonComment