A Comparison of Grip Strength and Selected Psychomotor Performance Measures in Healthy and Frail Elderly Females

Article excerpt

In 1991, an estimated 31.8 million elderly adults resided in the United States, including 19.0 million elderly women and 12.8 million elderly men (American Association of Retired Persons, 1992). In addition, by the year 2030, more than 22% of all Americans will be 65 or older. Thus, it is critically important to understand the biological, psychological, and behavioral changes that occur with increasing age, especially in women. Motor control research on older women is warranted due to the higher ratio of females to males in this age group and the high risk of limiting conditions involving functional ability, such as osteoporosis and arthritis (Horton, 1992). Studies which focus on exercise, strength, and movement control are likely to contribute to our understanding of health behaviors and activity patterns of older women (Woods, 1993).

Of particular concern to kinesiologists and health professionals is the risk of accidental injury associated with age and psychomotor declines. With advanced age comes the increased risk of disabling conditions and limitations in movement. For example, an older adult is likely to suffer a damaging fall by the time he or she reaches 80-85 years of age (Fiatarone & Evans, 1993; Schultz, 1992; Stelmach & Worringham, 1985; Woollacott, 1993).

In the last few years, interest has emerged which examines the relationship between musculoskeletal strength and functional ability in older adults. Musculoskeletal strength has been shown to be an important component of functional ability and is a major cause of limited mobility and activity, especially for women (Horton, 1992). Spirduso and MacRae (1990) stated,

Much research needs to be done to document and understand human strength and power capabilities in the older decades. It would be extremely useful to know the contribution that different levels of muscle strength and power might make toward the prevention of injuries, accidents, and fatalities in the very old. (p. 196)

In support of Spirduso and MacRae's (1990) position, several studies have demonstrated that one of the specific responses to strength training or advantages of greater musculoskeletal strength is superior recruitment and control of motor units (Moritani & deVries, 1979; Sale, 1987, 1988). Specifically, Moritani and deVries (1980) demonstrated that enhanced motor unit recruitment and control was important in strength improvements as a result of resistance training. Thus, stronger or strength-trained older individuals are more likely to show improved gross and fine motor movements.

As evidence of this relationship, Fiatarone et al. (1990) conducted a study which examined the relationship between strength and gross motor movements. Among the 20 frail male and female subjects (M age = 90 years), strength gains were 174% following training. An improvement in strength was associated with improvements in gross motor movements. Bassey et al. (1992) were interested in determining whether strength in frail elderly subjects was correlated with functional, gross motor performance activities such as rising from a chair and walking up stairs. Subjects in this study were 26 frail, institutionalized men and women who had many chronic health conditions. Significant correlations were found between leg extensor power and all functional performance measures. Bassey et al. concluded that leg power may be a useful measure in determining functional ability in a frail population of elderly adults.

Although Fiatarone et al. (1990) and Bassey et al. (1992) demonstrated that strength was important to gross motor movements, little information regarding the quality or efficiency of those improved movements was provided (Rosenbaum, 1991). One way to assess movement quality or efficiency is to utilize kinematics to examine movement characteristics. Detailed kinematic analyses may enhance understanding the control processes which are involved in movement production (Annett, 1988). …