The Masters Athlete

Understanding the Role of Sport and Exercise in Optimizing Aging

Joe Baker,Sean Horton,Patricia Weir

• Publisher: Routledge
• Year: 2009
• ISBN:
  9781134023486
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Applied Sciences
• Index: Technology & Engineering

Masters athletes are those that continue to train and compete, typically at a high level, beyond the age of thirty-five and into middle and old age. As populations in the industrialized world get older and governments become increasingly keen to promote healthy aging and non-pharmacological interventions, the study of masters athletes enables us to better understand the benefits of, and motivations for, life-long involvement in physical activity. This is the first book to draw together current research on masters athletes.

The Masters Athlete examines the evidence that cognitive skills, motor skills and physiological capabilities can be maintained at a high level with advancing age, and that age related decline is slowed in athletes that continue to train and compete in their later years. Including contributions from leading international experts in physiology, motor behaviour, psychology, gerontology and medicine, the book explores key issues such as:

• motivation for involvement in sport and physical activity across the lifespan
• evidence of lower incidence of cardiovascular disease, hypertension, and diabetes
• the maintenance of performance with age.

Challenging conventional views of old age, and with important implications for policy and future research, this book is essential reading for students and practitioners working in sport and exercise science, aging and public health, human development, and related disciplines.

SECTION TWO
AGING, PERFORMANCE, AND THE ROLE OF CONTINUED INVOLVEMENT

CHAPTER THREE
PEAK EXERCISE PERFORMANCE, MUSCLE STRENGTH, AND POWER IN MASTERS ATHLETES

HIROFUMI TANAKA

The age profile in the United States is shifting very rapidly as the first baby boomers move toward an older age structure crossing the retirement age threshold. It is estimated that by year 2030, one in every five Americans will be 65 years and older. Aging is associated with declines in functional capacity and increased risks of developing chronic diseases. However, being old is not the inevitable state of functional disability and illness. In fact, functional and health-related changes that we often associate with aging are in large part due to physical inactivity (Skinner et al., 1982). Short-term inactivity through bed rest and weightlessness produces substantial loss of muscle mass and strength (Kortebein et al., 2007; Volpi et al., 2004), whereas progressive strength training induces muscle hypertrophy and increases muscle strength and power (Anton et al., 2006; Miyachi et al., 2004). In this context, Masters Athletes are an effective experimental model of ‘primary aging’ and have challenged the negative stereotype of aging (Tanaka & Higuchi, 1998; Tanaka & Seals, 2003; see also Horton, Chapter 8). In essence, Masters Athletes represent the other extreme end of an aging distribution, a complete opposite to the frail elderly. This review will focus on the age-associated changes in muscle strength and power in Masters Athletes.

EXPERIMENTAL STUDIES ON MASTERS ATHLETES

Obviously in the data of athletic records we have a store of information available for physiological study. Apart from its usefulness, however, I would urge that the study is amusing. Most people are interested, at any rate in England and America, in some type of sport. If they can be made to find it more interesting, as I have found it, by a scientific contemplation of the things which every sportsman knows, then that extra interest is its own defense.

(Hill, 1925)

The Nobel laureate, A.V. Hill, pioneered the use of athletic performance data to examine the relation between maximal speed and racing distance (Hill, 1925). This experimental approach was later adapted for the study of aging, originally by Lehmann, who examined the relation between age and peak performance (Lehmann, 1953). Since then, a number of investigators have utilized this particular approach to address a number of questions pertinent to aging (Schulz & Curnow, 1988; Stones & Kozma, 1981; Tanaka & Seals, 1997; Tanaka & Seals, 2003). The increasing popularity of the use of athletic performance data to examine physiological aging can be attributed to a number of experimental advantages that the study of Masters Athletes could provide as shown below.

1. Extrinsic factors (e.g., deconditioning, chronic degenerative diseases) that often confound the intrinsic aging process can be minimized in Masters Athletes.
2. Athletic performance data contain rich sources of physiological information allowing insight into age-related changes in physiological functional capacity.
3. Masters Athletes maintain high levels of motivation and the drive to succeed.
4. Athletic performance data are very reliable as they are collected in well-controlled environments due to elaborate rules and closely monitored competitions (Henry, 1955).
5. Masters Athletes provide the gauge at which we can assess the physiological ceiling at older ages.
6. It is simply interesting and amusing. As illustrated by the popularity of the Olympic Games, people are fascinated by the athletic achievements and upper limits of what athletes can do in athletic events.

As in any other research field, experimental studies utilizing Masters Athletes and athletic performance data are not without limitations/weaknesses. Some of the major limitations associated with this experimental approach are: (a) secular changes related to more rapid growth of older Masters Athletes (Jokl et al., 2004); (b) influence of sociocultural factors (e.g., women were not allowed to compete in many athletic events in the past); (c) potential problem of generalizability to the entire aging population. Masters Athletes, at least those in the US, are mostly white and well educated (Wright & Perricelli, 2008), and may not be a true representative sample; (d) influence of non-physiological factors (e.g., changes and improvements in equipment and techniques) acting on athletic performance; and (e) potential fundamental differences between lifelong Masters Athletes and newcomers (i.e., possible differences in the effects of long-term and short-term training).

PHYSIOLOGICAL FUNCTIONAL CAPACITY WITH AGING

Physiological functional capacity (PFC) can be defined as the ability to perform the tasks of daily life and the ease with which these tasks can be performed (Tanaka & Seals, 2003). Determination of the effects of biological aging on physiological functional capacity is difficult because of the confounding factors that often change concomitant with aging (e.g., decline in physical activity, increase in chronic degenerative disease). Analysis of changes in peak sport performance is an effective approach to assess how physiological functional capacity is affected by the aging process as changes observed with advanced age in these Masters Athletes are thought to reflect mainly the results of primary aging. We have previously reported how physiological functional capacity, as assessed by running and swimming endurance performance, declines with advancing age (Tanaka & Higuchi, 1998; Tanaka & Seals, 1997; Tanaka & Seals, 2008; see also Stones, Chapter 2). Another, and arguably more important, component of physiological functional capacity in relation to aging is muscular strength and power. The age-associated decline in peak muscular power has important clinical and functional implications for the elderly. The ability to perform many activities of daily living may be compromised by low muscle strength and power even in healthy elderly persons. Because we cannot normally change the physical demands of our daily work with aging, a reduction in PFC means that aging workers labor closer to their maximal capacity, and that could result in chronic fatigue and other health problems (WHO Study Group, 1993). Additionally, a reduction in PFC in aging workers has economical implications. There was an interesting study published in the 1960s describing the trend whereby the average earnings of forest workers dropped progressively with advancing age despite the fact that average daily work time remained unchanged (Kilander, 1962).

AGE-RELATED DECLINES IN MUSCLE STRENGTH AND POWER IN SEDENTARY ADULTS

Skeletal muscle strength, one of the representative measures of functional capacity, begins to decline after age 30, with a more exponential decrease in strength after the age of 50 (Grimby & Saltin, 1983; Quetelet, 1842). Between the ages of 30 and 80, humans lose an average of 30–40 per cent of their muscle strength (around 40 per cent in the leg and back muscles and 30 per cent in the arm muscles; Grimby & Saltin, 1983; Holloszy & Kohrt, 1995). The primary mechanisms underlying this decrease in muscle strength with age, which is commonly referred to as ‘sarcopenia’, is a decline in muscle mass, as well as a decrease in muscle strength per unit muscle cross-sectional area (i.e., neural activation or muscle quality; Dutta & Hadley, 1995; Volpi et al., 2004). The consequences of sarcopenia can be extensive because there is an increased susceptibility to falls and fractures, impairment in the ability to thermoregulate, a decrease in basal metabolic rate, as well as an overall loss in the functional ability to perform daily tasks (Dutta & Hadley, 1995).

AGE-RELATED DECLINES IN MUSCLE STRENGTH AND POWER IN ENDURANCE-TRAINED MASTERS ATHLETES

It has been well established that regular aerobic exercise improves a number of cardiovascular functions, risk factors for cardiovascular disease, and overall functional capacity in older adults (Holloszy & Kohrt, 1995; Mazzeo & Tanaka, 2001). Because of the major role that habitual exercise plays in determining physical function, it is reasonable to speculate that regular aerobic exercise could have beneficial effects on muscle mass and muscle strength. However, as is apparent in the stereotypic appearance of Masters endurance-trained runners, regular aerobic exercise does not induce obvious muscle hypertrophy (Sugawara et al., 2002; Volpi et al., 2004) although an increase in muscle fiber area has been observed after intense endurance training in older adults (Coggan et al., 1992). Moreover, endurance training does not appear to attenuate or prevent loss of muscle mass with increasing age (Sugawara et al., 2002). Furthermore, rates of age-related decreases in anaerobic power, as assessed by vertical jumping performance, are essentially the same between sedentary and Masters Athletes (Grassi et al., 1991). Although a lack of effects of endurance training in modulating age-associated loss of muscle mass is certainly disappointing, it is important to recognize that muscle mass is not the only determinant of muscle function. It is possible that regular aerobic exercise induces beneficial effects on ‘muscle quality’, including neuromuscular components, in older adults (Volpi et al., 2004).

AGE-RELATED DECLINES IN MUSCLE STRENGTH AND POWER IN STRENGTH-TRAINED MASTERS ATHLETES

The age at which peak performance in lifting events is achieved occurs between 28 and 31 years of age (Schulz & Curnow, 1988). After that age, lifting performance starts to decline with advancing age. What is the temporal pattern of the decline in peak dynamic muscular power with age in strength-trained Masters Athletes? Is it a continuous (linear) decline or a curvilinear decrease with aging? In order to address these questions, we performed retrospective analyses of the data compiled from US weightlifting and powerlifting records (Anton et al., 2004). Weightlifting consists of two main events. The snatch is performed in a continuous movement from the bar on the floor to the fully extended arm position above the head, whereas the clean & jerk involves lifting from the platform to the shoulders in one motion, then thrusting the bar into a position overhead, and finally bringing feet together to complete the lift. Powerlifting consists of three events: (a) deadlift, (b) squat, and (c) bench press. In the deadlift, a competitor lifts a barbell off the ground from a bent-over position until the torso is fully upright. The squat involves lowering the torso by bending the knees and hips until the hip joint comes lower than the knee joint, and then standing back up. In the bench press, while lying on his or her back, a competitor lowers a barbell to the chest and then pushes it back up until the arm is fully extended.

Weightlifting performance declined curvilinearly with advancing age in both men and women, whereas age-related decrease in powerlifting performance was linear (see Figure 3.1). Additionally, the magnitude of age-related declines in weight-lifting performance was substantially greater than in powerlifting. Age-related declines in physiological functional capacity can be attributed to overall decreases in a number of physiological functions. Each lifting event is unique in that the degree to which each of the physiological systems is involved differs considerably. Weightlifting events require quickness and explosive power as well as more complex and exquisite neuromuscular coordination to lift the load. It is also critical to possess excellent balance throughout the lift. In contrast, speed is not a critical factor for powerlifting events, and the movement required in each event is relatively simple. These results suggest that more complex and explosive tasks that require a greater involvement of various physiological functions demonstrate greater decreases in physiological functional capacity with advancing age (Anton et al., 2004).

Another interesting observation is that age-associated reductions in performance were greater in women than in men in weightlifting events, whereas the rate and magnitude of age-related decrease in powerlifting performance were not different between the genders. This observation is consistent with physiological research indicating that women may undergo greater age-related reductions in muscle fiber type, shortening velocity at the single fiber level (Krivickas et al., 2001). Certainly, it is possible that sociocultural factors contributed to these observations, because the explosive nature of weightlifting may have discouraged more women from competing in these events.

Figure 3.1 Age-related decreases in weightlifting (an average of snatch and clean & jerk) and powerlifting (an average of deadlift, squat, and bench press) performance records in men and women (Anton et al. 2004) (reproduced with permission from Lippincott, Williams & Wilkins)

SEDENTARY VS. STRENGTH-TRAINED MASTERS ATHLETES

A clinically and functionally important question is whether the rate of decline in muscle strength and power with age is attenuated or absent in adults who perform regular resistance exercise. The notion that strength training performed on a daily basis will attenuate or prevent loss of muscle strength with age is a very positive message from the public health standpoint, and such notions have been promoted and described in textbooks (Wilmore & Costill, 2004). Surprisingly, only a few published studies are available to provide insight into this issue. In a study that compared Masters weightlifters and healthy untrained adults varying widely in age (Pearson et al., 2002), both peak muscle isometric strength and peak lower-limb explosive power declined with increasing age at a similar relative (per cent) rate in the weightlifters and sedentary controls. When the data in peak muscle power was expressed in absolute unit (in W/year), the rate of decrease was ~60 per cent greater in strength-trained adults (Pearson et al., 2002). Similar relative rates of age-related decline in anaerobic power have been reported between power-trained Masters Athletes and sedentary peers (Grassi et al., 1991). Thus, the available evidence is not consistent with the notion that regular strength training would prevent loss of muscle strength and power with increasing age. However, it is important to note from the standpoint of preventive gerontology that the absolute levels of muscle strength and power in strength-trained adults are substantially higher than those of their sedentary peers throughout the adult age range (Pearson et al., 2002). Accordingly, strength-trained adults possess higher levels of physiological functional capacity and lower risks of premature morbidity than sedentary adu...