Page 35 - Petelin, Ana, and Šarabon, Nejc. 2018. Eds. Zdravje starostnikov / Health of the Elderly. Znanstvena monografija / Proceedings. Koper: University of Primorska Press
P. 35
Physical activity role of physical activity and nutrition in prevention of frailty 35
Muscle mass and strength decrease with ageing. This process is accelerat-
ed after the age of 70 (Larsson et al., 1979). Reduced strength may lead to frailty
which is characterized by unintentional weight loss, low physical activity lev-
els, slow gait speed, exhaustion, and weakness (Fried et al., 2001). The main rea-
son behind strength and power decline is sarcopenia, loss of muscle mass with
age due to motor neuron death, immunological factors, hormonal change, in-
creased sedentary lifestyle and malnutrition (Narici & Maganaris, 2006).
On the other hand, strength training has potential to reverse or slow
down these processes even at older age (Harridge et al., 1999). Different train-
ing interventions have been shown to increase strength in healthy older adults
as well as in frail. Supervised center-based interventions seem to be more ef-
fective than home interventions at improving strength in frail older persons
(Binder et al., 2005; Pahor et al., 2006; King et al., 2002; Fairhall et al., 2014).
Researched interventions were of different durations, ranging from 8 weeks
up to 2 years. Even the shortest trial duration was enough to increase strength
(Serra-Rexach et al., 2011).
An important parameter of strength training is exercise load, i.e. intensi-
ty, usually expressed in % of 1RM. Low exercise load studies reported strength
gains less frequently. Siegrist et al. (2016) reported no strength gains after 16
week of a supervised exercise training program (1 hour/week) with strength
and power training, challenging balance and gait training with increasing, but
in general low, levels of difficulty. With fitness machines and loads of 60 % of
1RM substantial strength improvements were obtained (about 20 % in isomet-
ric exercises and about 100 % in lifting weights). Similar effects were seen in a
study by Binder et al. (2005), who used exercise loads of 70-80 % of 1RM. In the
oldest group of old persons, 70 % of 1RM load managed to improve leg press
strength by 20% after 8 weeks of hypertrophy type strength training. These re-
sults are in agreement with findings that resistance training in healthy older
persons with greater loads is related to greater increases in strength and power
parameters (Steib et al., 2010) and support a dose-response relationship.
Supplementation can enhance the effects of strength training (improved
strength and power gains). Amino acid supplementation (AAS) may promote
muscle growth but does not necessarily improve strength and power in healthy
older adults (Finger et al., 2015).
Aerobic capacity may be a limiting factor of mobility and work capaci-
ty in frail older persons. Its loss may be due to decreased muscle mass (Fleg &
Lakatta, 1988) or lower cardiac output (Ogawa et al., 1992). Ehsani et al. (2003)
studied cardiovascular adaptation in older mild-to-moderate frail subjects af-
ter endurance exercise at 78 % of peak heart rate. They found 14 % increase in
peak VO2 after 9 months of intervention and that the main adaptation was in-
crease in heart rate and probably stroke volume. It is not possible to conclude
on the optimal regime to improve endurance and VO2max.
Muscle mass and strength decrease with ageing. This process is accelerat-
ed after the age of 70 (Larsson et al., 1979). Reduced strength may lead to frailty
which is characterized by unintentional weight loss, low physical activity lev-
els, slow gait speed, exhaustion, and weakness (Fried et al., 2001). The main rea-
son behind strength and power decline is sarcopenia, loss of muscle mass with
age due to motor neuron death, immunological factors, hormonal change, in-
creased sedentary lifestyle and malnutrition (Narici & Maganaris, 2006).
On the other hand, strength training has potential to reverse or slow
down these processes even at older age (Harridge et al., 1999). Different train-
ing interventions have been shown to increase strength in healthy older adults
as well as in frail. Supervised center-based interventions seem to be more ef-
fective than home interventions at improving strength in frail older persons
(Binder et al., 2005; Pahor et al., 2006; King et al., 2002; Fairhall et al., 2014).
Researched interventions were of different durations, ranging from 8 weeks
up to 2 years. Even the shortest trial duration was enough to increase strength
(Serra-Rexach et al., 2011).
An important parameter of strength training is exercise load, i.e. intensi-
ty, usually expressed in % of 1RM. Low exercise load studies reported strength
gains less frequently. Siegrist et al. (2016) reported no strength gains after 16
week of a supervised exercise training program (1 hour/week) with strength
and power training, challenging balance and gait training with increasing, but
in general low, levels of difficulty. With fitness machines and loads of 60 % of
1RM substantial strength improvements were obtained (about 20 % in isomet-
ric exercises and about 100 % in lifting weights). Similar effects were seen in a
study by Binder et al. (2005), who used exercise loads of 70-80 % of 1RM. In the
oldest group of old persons, 70 % of 1RM load managed to improve leg press
strength by 20% after 8 weeks of hypertrophy type strength training. These re-
sults are in agreement with findings that resistance training in healthy older
persons with greater loads is related to greater increases in strength and power
parameters (Steib et al., 2010) and support a dose-response relationship.
Supplementation can enhance the effects of strength training (improved
strength and power gains). Amino acid supplementation (AAS) may promote
muscle growth but does not necessarily improve strength and power in healthy
older adults (Finger et al., 2015).
Aerobic capacity may be a limiting factor of mobility and work capaci-
ty in frail older persons. Its loss may be due to decreased muscle mass (Fleg &
Lakatta, 1988) or lower cardiac output (Ogawa et al., 1992). Ehsani et al. (2003)
studied cardiovascular adaptation in older mild-to-moderate frail subjects af-
ter endurance exercise at 78 % of peak heart rate. They found 14 % increase in
peak VO2 after 9 months of intervention and that the main adaptation was in-
crease in heart rate and probably stroke volume. It is not possible to conclude
on the optimal regime to improve endurance and VO2max.
