Effects of prolonged and maintenance strength training on force production, walking, and balance in aging women and men.

To examine effects of 21-week twice/week strength training (ST) period followed by an additional 21-week twice or once/week ST period on force production, walking and balance in aging people. Seventy-two women (58 ± 7 years; W) and 63 (58 ± 6 years) men (M) were randomized for the first 21-week ST period: STW and STM, control (C) CW and CM. Training participants were randomized for the second 21-week ST period: once/week STWx1 and STMx1, twice/week STWx2 and STMx2. LegPress, isometric leg extension rate of force development (RFD), walking time, and balance. First 21-week ST period: leg press, RFD, balance, and walking improved significantly in STW and STM. Second 21-week ST period: leg press first increased in STMx1 and STMx2, and then decreased to the level of 21 weeks in STMx2 and remained unchanged in STWx2 and decreased in STWx1 and STMx1. Walking and balance improved significantly in STWx1 and STWx2. A progressive 21-week ST period twice/week in aging people can lead to large improvements in maximal strength, walking time, and balance in both genders. A further strength training period with the same amount of training may maintain the strength gains, whereas balance and walking may be maintained with less training.

Resistance training induced increase in muscle fiber size in young and older men.

Muscle strength and mass decline in sedentary individuals with aging. The present study investigated the effects of both age and 21 weeks of progressive hypertrophic resistance training (RT) on skeletal muscle size and strength, and on myostatin and myogenin mRNA expression in 21 previously untrained young men (26.0 ± 4.3 years) and 18 older men (61.2 ± 4.1 years) and age-matched controls. Vastus lateralis muscle biopsies were taken before and after RT. Type I and type II muscle fiber cross-sectional areas increased more in young men than in older men after RT (P < 0.05). Concentric leg extension increased (P < 0.05) more after 10.5 weeks in young men compared to older men, but after 21 weeks no statistical differences existed. The daily energy and protein intake were greater (P < 0.001) in young subjects. Both myostatin and myogenin mRNA expression increased in older when compared with young men after RT (P < 0.05). In conclusion, after RT, muscle fiber size increased less in older compared to young men. This was associated with lower protein and energy intake and increases in myostatin gene expression in older when compared to young men.

Combined strength and endurance training improves health-related quality of life in healthy middle-aged and older adults.

The purpose of this study was to evaluate the effects of 21 weeks of strength and/or endurance training on health related quality of life (HRQoL) in 39-77 year-old healthy subjects. 108 men and 96 women were randomized into endurance, strength, or combined training groups and controls. Strength-group performed high-intensity strength training while endurance-group performed cycle training. Combined-group completed both training protocols. Leg extension strength and maximal oxygen uptake were measured. HRQoL was assessed with a Finnish version of SF-36 questionnaire. A significant training-induced difference was observed between groups (p=0.038) in the vitality dimension of HRQoL, which was characterized by a 6.6 ± 1.5 unit increase in the combined group and no change in the other groups. Both endurance and combined training showed small improvements in certain dimensions of HRQoL. Dimensions of general (4.6 ± 1.9) and mental health (3.9 ± 1.4) improved in combined-group while general health (4.4 ± 2.0), bodily pain (5.5 ± 2.5) and role physical (6.0 ± 2.4) improved in endurance-group. Strength-group experienced increased pain ( -5.4 ± 1.8) during the experimental period. However, increased perception of pain was not observed during combined training. According to the present results both endurance and especially combined training may have potential to promote or maintain certain dimensions of HRQoL even in middle-aged and older adults.

Effects of strength, endurance and combined training on muscle strength, walking speed and dynamic balance in aging men.

The aim of this study was to examine effects of 21-week twice weekly strength (ST), endurance (ET) and combined (ST + ET 2 + 2 times a week) (SET) training on neuromuscular, endurance and walking performances as well as balance. 108 healthy men (56.3 ± 9.9 years) were divided into three training (ST; n = 30, ET; n = 26, SET; n = 31) groups and controls (C n = 21). Dynamic 1RM and explosive leg presses (1RMleg, 50%1RMleg), peak oxygen uptake using a bicycle ergometer (VO(2peak)), 10 m loaded walking time (10WALK) and dynamic balance distance (DYND) were measured. Significant increases were observed in maximal 1RMleg of 21% in ST (p < 0.001) and 22% in SET (p < 0.001) and in explosive 50%1RMleg of 7.5% in ST (p = 0.005) and 10.2% in SET (p < 0.001). VO(2peak) increased by 12.5% in ET (p = 0.001) and 9.8% in SET (p < 0.001). Significant decreases occurred in 10WALK in ST (p < 0.001) and SET (p = 0.003) and also in DYND of -10.3% in ST (p = 0.002) and -8% in SET (p = 0.028). The changes in C remained minor in all variables. In conclusion, ST and SET training produced significant improvements in maximal and explosive strength, walking speed and balance without any interference effect in SET. Significant but moderate relationships were observed between strength and dynamic balance and walking speed, while no corresponding correlations were found in the ET group.

Load carrying walking test and its relationships to endurance and neuromuscular capabilities in women and men of different ages.

The aim of this study was to examine load carrying walking test (TMload) performance on the treadmill and its associations to endurance and neuromuscular capabilities in women and men of different ages. Sixty participants (aged 28 to 71 years) were divided into young, middle-aged and old groups of both genders. Clinical stress test was performed by stationary cycle ergometer (CEload). Peak oxygen uptake (VO2peak), heart rate and lactate concentration were measured using maximal TMload test. Isometric strength and EMG-activity of upper and lower extremities were measured before and after TMload. VO2peak of TMload correlated significantly with TMload exercise time (ET) in all other groups (r=0.67 to 0.91 and p ≤ 0.05 to p<0.001) except old men. Leg extension force decreased (p ≤ 0.05 to p<0.001) after TMload in all groups, grip force in young groups (p ≤ 0.05), while plantar flexion force and all EMGs remained unchanged. In men VO2peak explained 81% and in women VO2peak and age explained 87% of the total variation of the TMload ET. In conclusion, ET of TMload is associated with high VO2peak, but not with muscle strength or its changes during the loading. The present load carrying walking test may be used for testing workers with heavy loading in their occupation or in rehabilitation purposes. Further research is needed to examine in more detailed the loading model of the present study as well as the effects of different types of training on load carrying performance.