Maximum voluntary isometric pinch contraction and force-matching from the fourth to the eighth decades of life.

Understanding the effects of age and gender on pinch strength, variability, and accuracy and how one's hand function changes with age better enables those in the preventative and rehabilitative fields to combat these losses. The present study examined fine motor maximum pinch strength [maximum voluntary isometric contraction (MVIC)] as well as the ability to maintain 5% MVIC accurately and consistently in five decades. One hundred adults in five groups, 20 in each decade of life from 30 to 79 years old, were nonrandomly recruited from the community. A two-way analysis of variance applied to MVIC, and a two-way multivariate analysis of variance applied to the variability (coefficient of variability) and accuracy (root mean square error), plus correlation and regression analyses, were used to determine decade and gender effects on pinch force. The task involved using isometric pinch control of a computer cursor to match a 5% of MVIC force level represented by a horizontal line. MVIC and force-matching steadiness and accuracy across all ages were not significantly different until the eighth decade (P<0.01). Men were stronger (P<0.001) but performed low-level force-matching with greater error (P<0.001) than women. Strength was not correlated with steadiness but was weakly correlated with accuracy (r=0.293, P<0.01), and steadiness and accuracy were strongly correlated (r=0.783, P<0.001). Decade and gender were moderate and strong predictors of accuracy and steadiness, respectively. In conclusion, age and gender differences were evident in pinch-force strength and control.

Age and practice effects on inter-manual performance asymmetry.

Manual dexterity declines with increasing age, however, the way in which inter-manual asymmetry responds to aging is unclear. Our purpose was to determine the effect of age and practice on inter-manual performance asymmetry in an isometric force pinch line tracing task that varied in difficulty within segments. Thirty right-handed participants, five males and five females in each of three age groups, young (Y20), young-old (O70), and old-old (O80), practiced an isometric force pinch task for 10 trials with each hand on each of five consecutive days. Inter-manual performance asymmetry of the right and left hands was analyzed with a repeated measures analysis of variance (ANOVA) of asymmetry with age groups, practice, task difficulty, and hand as factors. The within-individual magnitude of asymmetry was also analyzed with a repeated measures ANOVA of manual asymmetry calculated as an asymmetry index (AI). Post hoc pair-wise comparisons were performed when significance was found. We observed no inter-manual performance asymmetry on this isometric tracing task among any of the age groups, either in the hand performance differences or in the magnitude of the AI. Age and practice interacted in terms of manual performance: the Y20 and O70 group improved accuracy and task time across the 5 days of practice but the O80 group did not. However, practice did not differentially affect the AI for accuracy or task time for any group. Accuracy of performance of the two hands was differentially affected by practice. All age groups exhibited poorer performance and larger AIs on the most difficult segments of the task (3 and 6) and this did not change with practice.

Long-term effects of three multicomponent exercise interventions on physical performance and fall-related psychological outcomes in community-dwelling older adults: a randomized controlled trial.

OBJECTIVES: To determine the long-term effects of three strength and balance exercise interventions on physical performance, fall-related psychological outcomes, and falls in older people. DESIGN: A single-blinded, four-group, randomized controlled trial. SETTING: Community, Germany. PARTICIPANTS: Community-dwelling adults aged 70 to 90 who had fallen in the past 6 months or reported fear of falling. INTERVENTION: After baseline assessment, 280 participants were randomly assigned to the control group (CG; no intervention; n = 80) or one of three strength and balance exercise interventions (the strength and balance group (SBG; strength and balance only; n = 63), the fitness group (FG; strength and balance plus endurance training; n = 64), or the multifaceted group (MG; strength and balance plus fall risk education; n = 73). The interventions consisted of 32 one-hour group sessions in 16 weeks. MEASUREMENTS: Data on physical performance, fall-related psychological outcomes, and falls were collected for 24 months. RESULTS: Mixed-effects regression analyses showed improved short- and long-term (12 and 24 months, respectively) physical performance for the SBG and FG, particularly regarding mobility, balance, and walking speed (P < .05). The improvements in physical performance outcomes were most prominent in the FG. Fall-related psychological outcomes, number of falls, and injurious falls were not significantly different from in the control group. CONCLUSION: Training focusing on strength, balance, and endurance can enhance physical performance for up to 24 months in community-dwelling older adults. These findings did not translate to improved fall-related psychological outcomes or reduced incidence of falls. This demonstrates the need for a different approach (e.g., regarding intervention dose and components) to gain intervention benefits in the multiple domains that contribute to independence and well-being in older adults.

The effects of age on precision pinch force control across five days of practice.

The effects of age on control of fingertip forces, across five days of practice, were determined for an isometric precision pinch grip task. The task involved controlling a computer cursor so that it traveled upward and horizontally on a 45 degree template line by applying X-axis isometric force with contraction of the thumb, and Y-axis force with the index finger. Upon reaching a reverse circle target, the cursor was returned to the start by controlling the steady release of isometric force. Participants' control across the 6 segments of the template line (3 applying and 3 releasing force) was examined. Healthy participants comprised three age groups: Y20 (mean = 21 ± 4 years), O70 (mean = 70 ± 3 years) and O80 (mean = 79 ± 3 years). The results indicated that 1) overall the Y20 group was faster in completing the task than the O80 group, 2) age differences in task duration time (speed) increased over 4 days, 3) the Y20 and O70 groups, but not the O80 group, improved performance (increased accuracy and decreased within-participant variability for time and accuracy) with practice, 4) circle target proximity (segments 3 and 6) was a potent factor; all groups were slower, less accurate, and less consistent irrespective of force direction in the segments approaching a circle target goal (reverse/end). A task maneuver preceding a directional reversal of force modulation, from increasing to decreasing, was the most difficult element for the O80 group followed by the O70 and Y20 groups. These old adults improved tracing accuracy and consistency, but not performance speed with practice on this precision pinch force control task.

Age-related declines in anaerobic muscular performance: weightlifting and powerlifting.

PURPOSE: One approach to studying the effects of aging on physiological functional capacity (PFC) in humans is to analyze the peak physical performance of trained athletes with increasing age. The primary aim of the present study was to determine weightlifting and powerlifting performance with increasing age in both men and women. METHODS: We performed a retrospective analysis of top age-group weightlifting and powerlifting records compiled from the U.S. Weightlifting and U.S. Powerlifting Organizations. RESULTS: Regression analyses showed that in both men and women weightlifting and powerlifting performance declined curvilinearly and linearly, respectively. The rate and the overall magnitude of declines in performance with age were markedly greater (P < 0.05) in weightlifting than in powerlifting. The rates of age-related decline in muscular power were not different between upper body (bench press) and lower body (squat). Similarly, the age-related declines were not different between snatch and clean and jerk in weightlifting events. The magnitude of the declines with age was greater (P < 0.05) in women than in men in weightlifting; no such sex-related differences were observed in powerlifting performance. CONCLUSIONS: The findings in this cross-sectional study indicate that 1) peak anaerobic muscular power, as assessed by peak lifting performance, decreases progressively even from earlier ages than previously thought; 2) the overall magnitude of decline in peak muscular power appears to be greater in tasks requiring more complex and powerful movements; 3) the age-related rates of decline are greater in women than in men only in the events that require more complex and explosive power; and 4) upper- and lower-body muscular power demonstrate similar rate of decline with age.