Traditionally, high-intensity power and resistance training was reserved for athletes striving to enhance sport-specific performance.
All that changed with the emergence of CrossFit®, P90X® and similar programs that have helped many average adults enjoy the challenges and benefits of high-intensity training. The abundance of young and early-middle-aged adults experiencing results from high-intensity exercise raises a few questions: What about older adults—are power training and high-intensity exercise safe for them? If so, what are the benefits for this population, and what type of programming is safe?
Many fitness professionals working with older adults follow the American College of Sports Medicine guidelines, which recommend an emphasis on strength endurance using lighter weights. While this cautious approach is better than no exercise at all, research suggests that high-intensity exercise—specifically heavy resistance and power training—is safe for older adults and can greatly improve their functional strength for many activities of daily living (Lohne-Seiler, Torstveit & Anderssen 2013; Sayers & Gibson 2010; Caserotti et al. 2008; Hazell, Kenno & Jakobi 2007; Porter 2006).
Another benefit of power training and high-intensity exercise for older
adults is increased production of the hormones testosterone, growth hormone and insulin-like growth factor-1 (IGF-1), which promote the muscle growth that can lead to a more youthful appearance (Baker et al. 2006; Godfrey & Blazevich 2004; Izquierdo et al. 2001).
ACSM Resistance Training Guidelines for Older Adults
These guidelines can provide a starting point for working with older clients.
- Frequency. Two to four times per week with 48 hours of rest between resistance training sessions.
- Exercise selection. One to two multi joint exercises for each of the large muscle groups: legs, abdomen, back, chest, shoulders and arms; machines recommended over free weights, for safety.
- Intensity. 65%–75% of one-repetition maximum (1-RM).
- Repetitions. 10–15.
- Sets. 1–3.
- Rest interval. 2–3 minutes between sets.
These guidelines are based on general resistance training guidelines for developing strength endurance. ACSM recommends a low-to-moderate intensity range of 65%–75% of 1-RM to boost strength and reduce the risk of injury
(Willoughby 2013). Applying the ACSM guidelines will provide some health benefits, but research suggests that older adults can and should progress to high-intensity strength and power training.
How Aging Affects Muscle Function
A foundational principle of exercise program design is reversibility, which means the body can lose many of the benefits of exercise if a person stops exercising (Baechle & Earle 2008). Inactivity and aging can cause preventable health issues like sarcopenia (loss of muscle mass), which can diminish the quality of life.
We lose about 5% of skeletal muscle mass per decade after age 40, with losses greatly accelerating after age 65 (Candow et al. 2011). Muscular atrophy and diminished neuromuscular efficiency from reduced conductivity of type II motor units lead to further losses of muscle strength and power output, with power declining more quickly than strength.
Age-related loss of muscle mass and force output is directly related to the onset of motor impairments and functional disability, which greatly increase the risk of falls (Lohne-Seiler, Torstveit & Anderssen 2013; Caserotti 2010; Sayers & Gibson 2010; Hazell, Kenno & Jakobi 2007; Porter 2006; Fielding et al. 2002). Studies confirming the link between muscle power and functional mobility have demonstrated that peak muscle power is a strong predictor of disability and functional limitation in the elderly (Fielding et al. 2002).
Strength vs. Power
Strength represents the amount of force a muscle can generate. Power, the velocity of force being produced, represents the speed at which muscle motor units innervate their attached muscle fibers, known as the rate of force production. While strength and power are related, they are separate characteristics that should be trained independently (Baechle & Earle 2008).
Rate of force production determines the magnitude of a movement’s accel- eration and influences the velocity of movement, both of which are important during many functional tasks and daily activities (Caserotti 2010; Caserotti et al. 2008; Porter 2006). For people over age 60, age-related loss of muscle power can occur approximately twice as quickly as loss of muscle strength, suggesting that muscle power is a more critical variable in age-related functional decline (Sayers & Gibson 2010; Fielding et al. 2002).
The Benefits of Power Training for Older Adults
Just as a sedentary lifestyle can threaten the health of older adults, an exercise program with appropriate levels of strength and power training can provide numerous health benefits and can stimulate muscle growth even in the later years of life. The factors contributing specifically to the loss of muscle mass, strength and power—namely, muscle atrophy, reduced activation of type II motor units and fibers, and oxidative stress—are also related to the production and utilization of testosterone, growth hormone and IGF-1 (Izquierdo et al. 2001). Increasing an older adult’s strength and power not only improves muscle function but also increases production of these anabolic hormones responsible for promoting muscle growth.
“High-intensity exercise seems to provide a stimulus for hormone production and could thus be the first choice for optimizing hormone profiles and improving physical performance in aging individuals,” concluded Godfrey & Blazevich (2004). A significant body of evidence also suggests that high-intensity exercises can be more effective for older adults than lower-intensity exercises by improving factors such as gait speed, walking endurance, and time to stand from being seated in a chair (Caserotti 2010; Hazell, Kenno & Jakobi 2007; Porter 2006)
One study (Caserotti et al. 2008) focused exclusively on the lower limbs, owing to their essential role in many activities of daily life, and investigated the effects of a 12-week program featuring explosive resistance training on both old (60–65) and very old (80–89) women. The program was conducted 2 days per week with 2 days of rest between workouts; it featured 4 sets of each exercise with training loads of 75%–80% of 1-RM and 8–10 repetitions. Exercise tempos focused on an explosive concentric action followed by a slower eccentric lengthening phase.
Results showed that this type of high-intensity program improved functional strength in both age groups. The researchers stated that “our findings demonstrate that explosive-type heavy-resistance training seems to be safe and well tolerated in healthy women even in the eighth decade of life and elicits adaptive neuromuscular changes in selected physiological variables that are commonly associated with the risk of falls and disability in aged individuals.” This research on women is important because they have less muscle mass than men and can experience a more rapid loss of functional strength (Casertotti et al. 2008; Farinatti et al. 2013).
When designing exercise programs for older clients, it is important to consider workout frequency. A separate study conducted on women in their 60s and 70s compared high-intensity resistance training frequencies of once, twice and three times per week. All three groups increased strength over the 9-week study, but the three-sessions-per-week group experienced the greatest increase in functional strength (Farinatti et al. 2013).
Designing an Effective Strength and Power Program for Older Adults
The ACSM guidelines point to the risk of injury from heavy resistance training, but research suggests that heavy resistance and power training are safe for older adults when properly supervised. According to Porter (2006), “The available evidence indicates that power training is more beneficial than strength training for increasing power, which can improve functional capacity in older adults.” The only risk of injury mentioned in the literature arose when study participants with minimal exercise experience performed initial testing of their baseline strength and power (Sayers & Gibson 2010; Hazell, Kenno & Jakobi 2007; Porter 2006)
It is not appropriate to start any client with high-intensity exercises, and this is especially true for older adults, who may have existing medical concerns or limited experience with resistance training. Applying the ACSM guidelines for an initial phase of training can help clients develop strength and learn proper movement mechanics before progressing to the higher-intensity training that will provide the overload for stimulating muscle growth.
Conducting testing before designing a program is not necessary; simply following the suggested guidelines for strength and power can help identify
an appropriate load and repetition range. To improve strength, the intensity should allow no more than 8–10 repetitions, fatiguing by the last repetition. Explosive power training should be limited to 6–8 repetitions, depending on the complexity of the movement and the amount of muscle mass involved (Baechle & Earle 2008).
A safe application of heavy resistance training with older adults is via fixed path-of-motion machines. A safe application of power training is to have older adults focus on explosive concentric muscle actions by throwing objects such as medicine balls, SandBell® weights or the ViPR®. Throwing increases the rate of force production for concentric muscle actions and minimizes the risk of injury by removing the high eccentric forces caused by decelerating or catching an external load.
Just as athletes have used power training for years to enhance sport-specific performance, older adults can use power training to improve their functionality and ability to perform activities of daily living. Many experts agree that age-related muscle atrophy and loss of strength can be addressed and overcome with appropriate application of high-intensity training (Candow et al. 2011).
Exercise programs that improve force production (strength) and rate of force production (power) while also increasing the body’s supply of hormones responsible for muscle growth can help older clients retain their youthful energy levels and appearance. This creates a marketing opportunity for fitness professionals, who can legitimately offer anti-aging exercise programs to their older-adult clients.
|Exercise Selection||Intensity||Tempo||Reps||Sets||Rest Interval (minutes)|
|Monday & Friday: Power|
|medicine ball chest throw||12 pounds||explosive||6–8||3–4||1–2|
|SandBell slam||10 pounds||explosive||6–8||3–4||1–2|
|kettlebell swing||12 kilograms||explosive||6–8||3–4||1–2|
|ViPR push-press||12 kilograms||explosive||6–8||3–4||1–2|
|heavy rope pulse||30 seconds||3–4||1–2|
|Wednesday: Machine-Based Strength|
|leg press||80% 1-RM||1/0/1||6–8*||3–4||1–2**|
|seated row||80% 1-RM||1/0/1||6–8||3–4||1–2|
|chest press||80% 1-RM||1/0/1||6–8||3–4||1–2|
|shoulder press||80% 1-RM||1/0/1||6–8||3–4||1–2|
|biceps curl||80% 1-RM||1/0/1||6–8||3–4||1–2|
|triceps extension||80% 1-RM||1/0/1||6–8||3–4||1–2|