AGING ATHLETES CHANGES IN RUNNING STRENGTH ABILITY AGING

AGING ATHLETES - CHANGES IN RUNNING & STRENGTH ABILITY

AGING – Aging is a process of becoming older , a process that is genetically determined & environmentally modulated. The study of aging is GERONTOLOGY, is a relatively new science that has made incredible progress over the last 30 years. Aging is a complex interaction of Genetics, Chemistry , Physiology, & Behavior.

Effects of Aging on Strength Sarcopenia – Loss of muscle mass with age in humans; is well documented. A reduction in muscle strength is directly associated with loss of muscle mass.

Consequences of Sarcopenia Individuals are more susceptible to falls and fractures Muscle atrophy appears to result from a gradual loss of both muscle fibre size and number. A gradual loss in muscle cross -sectional area is consistently found with advancing age; by age 50, about 10% of muscle area is lost. After 50 years of age, this rate accelerates significantly. Muscle strength declines by approx. 15% per decade in the sixties and seventies and by about 30% thereafter.

CHANGES IN STRENGTH WITH AGING

Strength Considerations Resistance training can make significant gains in strength. A two to threefold increase in strength can be accomplished in three to four months. With more prolonged resistance training, even a modest increase in muscle size is possible. Strength training, in addition to its possible effects on bone density, energy metabolism, and functional status, is also an important way to increase levels of physical activity in the elderly.

At the age of 40, muscle strength began to gradually decline. Muscle strength of males in their 20 S was 45± 7 kg and 43± 6 kg in their right (RT) and left (LT) quadriceps respectively. A decline with aging was represented by 22± 5 kg and 20± 5 kg in the RT and ISSN 2078 -4724) (The Effects of Aging on Muscle Strength and Functional Ability) LT quadriceps muscles respectively by the 7 th decade of life. (World Journal of Sport Sciences 2 (4): 261265, 2009

Table : Mean±SD of muscle strength(Quadriceps) tests of different age groups (In Kgs) LT 20 s RT 45± 7 30 s 43± 5 42± 4 40 s 34± 7 32± 5 50 s 30± 6 29± 6 60 s 24± 7 22± 8 70 s 22± 5 20± 5 Decade (yr) 43± 6

Strength Considerations Resistance training can maintain or increase the muscle fiber cross-sectional area in older men & women. Aging appears neither to impair the ability to improve muscle strength nor to prevent muscle hypertrophy. Example – when older men(60 -70) strength trained for 12 weeks at 80% of their one repetition maximum for extension & flexion of both knees , their extension strength is increased by 107% & flexion strength increased by 227%.

Changes In Muscle Fibre With Aging Decrease in both number & size of muscle fibers occur with aging. Approximately 10% of the total number of muscle fibers are lost per decade after age 50. Increase in slow twitch fibers because the number of fast twitch motor neurons decreases during aging. Muscle tone declines about 22% by age 50.

Muscle Fiber Changes With Aging

At What Age Do Runners Begin to Slow? Sprinters slow at an earlier age. The rate of decline increases with aging. Endurance athletes begin to slow in the mid to late 30 s.

What Are the Reasons for the Performance Decline? Reduced Aerobic Capacity Injury (Effects of co-morbidity) Reduced training volume and intensity Physiological factors Psychological factors Cultural factors

Physiological Factors Decrement in maximal oxygen uptake Movement(runn ing) economy -are the primary determinants of distance running performance. Reduced Aerobic Capacity Aging hampered lactate threshold(La ctic acid tolerance), and

Physiological Factors The primary factor responsible for lower VO 2 max is a lower maximal heart rate. Max VO 2 = Cardiac Output (Stroke Volume x Heart rate) x peripheral oxygen extraction ( arteriovenous oxygen difference)

CHANGES IN VO 2 MAX WITH AGE

Physiological Factors………… Lower VO 2 max , result of reduction in maximum cardiac output Aerobic capacity decreases about 1% per year after age 25 Aging causes increased peripheral resistance, & as a result blood pressure is increased at rest & during exercise.

Co-morbidity • Effects of co-morbidity i. e. of primary diseases or injuries that are in principle independent of age, but which are accumulate during the lifespan.

Training Volume and Intensity Ø Aging affects the ability to sustain training intensity. Ø Aging affects recovery. Ø Reduced frequency and intensity impair the optimal maintenance of physiological factors that determine performance.

Aging and Flexibility Connective tissues between muscles and bones become more rigid with aging. The restriction in the range of movement at major joints used in running will diminish running speed by reducing stride length. Poor flexibility increases the risk for injury. Injury leads to a decrease in training frequency, duration, and intensity.

What Is the Rate of Performance Decrement? • Research indicates that runners who remain highly fit can expect a 0. 5 to 1 percent decline in performance per year from age 35 to 60. After age 60, performance decrement tends to increase at a faster rate. • Vigorous training reduces the decrement by approximately half from the relatively sedentary individual.

Age Graded Example 53 -year-old male who runs a 3: 05: 30 marathon would have a Performance Level Percentage of 76. 7 percent. This percentage was obtained by dividing the world record of 2: 21 for a 53 -year-old male by 3: 05: 30. This time of 3: 05: 30 would convert to an equivalent prime-age performance of 2: 45: 17.

Age Graded Tables Website: http: // misweb. cbi. msstate. edu/~rpe arson/masters. html

Aging Considerations Maintain healthy body weight Cross train Stretch! Weight train Consider less frequent training with lower volume, but maintain intensity.

Despite the popularized fact that the aging process is associated with loss of physiologic function with age, many of these changes can be reversed &/or blunted through proper aerobic & resistance training programs up to the limited extent.

Trainability Of The Older Athlete Endurance Exercise Ø Produce similar gains in healthy people regardless of their age, sex, or, initial fitness level. Ø Produces greater improvement in muscle oxidative enzyme activities than in younger endurance-trained people. Resistance Exercise Ø Produces increases in muscle strength & muscle hypertrophy.

“Never put an age limit on your dreams, ” -- Dara Torres, U. S. gold Medallist in swimming. (she is the only swimmer represents America in Olympic Games (1984, 1988, 1992, 2000 and 2008), and, at age 41.

REFERENCES Ø FOSS, L. MERLE , & keteyian , J. STEVEN(1998). Fox Physiological Basis For Exercise & Sport. Mc. Graw –Hill Book Company- Singapore. 399, 400. Ø Jack, H. Wilmore & David, L. Costill (1994). Physiology Of Sport & EXERCISE. 426 -437. Ø Shaver, G. Larry(2002). Essentials Of Exercise Physiology. 243, 245.