Effects of Aging

Strength and muscular power are important in maintaining functional abilities to allow us to perform activities of daily living such as carrying groceries, getting out of a chair, taking out the trash, climbing stairs, etc.

Age related strength losses vary between sexes and muscle group. Studies demonstrate muscular strength decreases by approximately 15% per decade in the sixth and seventh decade, and 30% thereafter.

The loss of strength and muscular power is largely brought about by both a loss of smaller motor units and a loss of muscle mass. A significant loss of muscle mass and strength occurs in the sixth decade of life, with perhaps a more dramatic decrease in women. This can be particularly problematic for women because they have less muscle mass.

The loss of muscle mass can be a result of shrinking muscle fibers (atrophy), loss of muscle fiber (sacropenia), or both (Frontera et al 1988). This loss of muscle fibers results in fewer type II muscle fibers, which would negatively affect muscular power.

A loss of functional ability begins earlier, by the age of 40, with the muscles' loss of maximal voluntary and speed of contraction (Paasuke et al. 2000). The ability to produce a force rapidly can decrease more than decrements in strength, particularly at older ages.

Benefits of Weight Training

Weight training has shown to be beneficial across every age group, including seniors and even those with chronic illness. Some of the most noteworthy benefits include decreased fear of falling and diminished age-related declines in muscle mass, strength, and muscular power.

Resistance training can enhance muscle mass and function even in 90 year old subjects (McComas 2005). Individuals over the age of 90 have been shown to make significant strength gains on a weight training program (Fiataron et al. 1990). Furthermore, long term involvement in weight training appears to increase absolute strength capabilities and slow down strength loss.

Muscular power improved significantly in the elderly (average age of 77 years) when performing high velocity resistance training. The largest power improvements were seen on leg press exercise, performed with 60-70% of bodyweight. The power improvements were associated with significant improvements in walking ability.

Falling is the leading cause of fatal and non-fatal injuries for the elderly, ages 65 and older. One in three adults fall yearly and cost the American health care system $30 billion per year (CBS News 2014). Elderly (ages 67 to 97 years of age) who participated in a free weight program reported a decreased fear of falling in addition to increased functional performance (Brill, et. al. 1998).

Program Considerations

Adults older than 45 years of age should consult with a licensed health practitioner before engaging in a vigorous exercise program, particularly if they have certain medical concerns. Also see Exercise Readiness Questionnaire and Risk Classification Form.

When older adults begin a weight training program, the general process is essentially the same for that of younger deconditioned novice. Most of the same rules apply with consideration of reduced recovery ability and initial physical condition of the trainee. The basic principles of adaptation will apply as long as the health of the individual remains intact. However, changes in the body's physiology occur that make the individual somewhat less adaptive to an exercise stimulus (Rippetoe and Kilgore, 2006).

Exercise tolerance to a particular workout should be a major consideration when training as we age. When beginning a weight training program, intensity should be quite modest and the number of exercises and sets should be kept to a minimum, to allow adequate adaptation and to prevent aversions to excessive efforts at this early stage. Participants can take several workouts to identify their beginning exercise resistances. See conservative method under identifying initial resistances.

The muscles' ability to produce a force rapidly, serves as a protective mechanism when falling. One of the top causes of injury in the elderly are falls, which sometimes leads to death. For this reason, improving muscular power should be an important training goal for the elderly.

People over 50 years of age commonly have joint and muscle discomfort after a heavy workout. Therefore, the frequency of intense workouts should be carefully programmed. See study summary on varying workloads in older adults. If joint pain or stiffness is still experienced, then the frequency of heavy loading day must be further reduced or the repetition training zones must be altered accordingly.

Since older individuals may have diminished ability to deal with increases in muscle and blood acidity, rest between sets should not be reduced quickly. Pay particular attention to adverse reactions such as nausea and dizziness when reducing length of rest periods in all participants, especially to individuals over 50 years of age, due to reduced buffering capacity.

The natural breath holding (Valsalva maneuver) during heavy lifts can result in an undue raise in blood pressure. This is a particular concern for those with cardiac problem, a family history of cardiac problems, or unstable left ventricular function. Older participants should be advised to avoid or minimize momentary breath holding during lifts. For this reason, they should not be encouraged to train to complete failure, and if it should occur, breath holding should be discouraged.

ACSM recommended a repetition range for individuals older than age 50-60 years of age or frail persons is 10 to 15 repetitions (see Suggested Repetition Ranges). Although more advanced and healthy older adults can perform lower repetition ranges with heavier weight (80% of 1RM or higher) for greater strength gains with relatively little risk of injury. Also see ACSM Recommendations for Resistance Training Exercise.

Masters Athletes

As the population ages, masters competitions become more prevalent in many sports. The strength sport, powerlifting, has a long tradition of masters athletes winning in open competition. (Rippetoe and Kilgore, 2006)

Master powerlifters over the age of 65 weight 180 lbs (81 kg) have squatted over 350 lbs (159 kg) (Harder 2000). At the age of 72, Darrell Gallenberger deadlifted an impressive 396 lbs at the 2001 North Texas Senior Olympics (Times Record News, Wichita Falls, TX, March 29, 2011).

However, even competitive weightlifters undergo a nonlinear decline in strength with age (Meltzer 1994). Peak anaerobic power in both power and endurance athletes decreases linearly at around 1% a year (Grassi et al. 1991).

The recovery capacity of a masters athlete is generally less than their younger counterpart, so periodization of training becomes even more important for the serious masters competitor. Periods of recovery should be longer and more pronounced than for younger athletes. When using undulating periodization models, the recovery microcycles should have a larger percentage of intensity reduction than for younger athletes, 10-15% rather than the 5% frequently used. Beyond 30 years of age, a volume reduction of 5% per decade is suggested. (Rippetoe and Kilgore, 2006)

References

CBS Evening News. Aug 30. 2014. Minutes 13:29-13:43.

Fleck SJ, Kreamer WJ (2007). Optimizing Strength Training. Human Kinetics, 164-165.

Hunter GR, Wetzstein CJ, McLafferty CL Jr, Zuckerman PA, Landers KA, Bamman MM (2001). High-resistance versus variable-resistance training in older adults. Med Sci Sports Exerc. 33(10):1759-64.

McComas AJ (2005) Skeletal muscle: Form and function. Human Kinetics (2).

Rippetoe M, Kilgore L (2006). Practical Programming for Strength Training. The Aasgaard Company, 253-256.