Older Adult & Exercise
Ageing & the Effect on Body Systems
Aerobic Exercise Guidelines
​
Resistance Training
Guidelines
​
​
Introduction
The ageing process is typically accompanied by an array of physiological changes, all of which present some degree of challenge to health and wellness, including both physiological and psychological functioning. As we age the body tissues and systems start to degenerate affecting optimal functioning. The three main areas that have significant effects on physical functioning include the muscular system, cardiorespiratory system, and the brain and nervous system. After the age of 50, approximately 5-to-10% of muscle loss occurs per decade coupled with 10-to-30% bone loss. There are also metabolic declines of 2-to-3% per decade that lead to fat accumulation and other negatively associated conditions. Other adverse changes that occur include cardiorespiratory system modifications that affect the individual’s aerobic capacity and functioning (Kasch et al., 1990; Lakatta, 1990) and an elevated risk of coronary heart disease (Singh, 2004).
The following areas are discussed: (1) physiological changes related to ageing; (2) results of resistance training and aerobic endurance training on ageing aspects; (3) suggested training protocols and procedures for older adults.
Ageing and the Muscular System
Muscle is necessary for muscular actions, and without regular movements, the individual’s health, physical fitness, and quality of life declines rapidly. Intriguingly, muscle tissue also produces and releases hormone-like substances (myokines) that have endocrine effects on the body’s other organs. Pedersen (2011) noted that these myokines may contribute to exercise-induced protection against numerous chronic physical inactivity syndromes. Studies have displayed evidence that muscular fitness has a profound and extensive influence on physical function (Holviala et al., 2006; Kalapotharakos et al., 2005) which is particularly important during the older adult stage of life.
​
Holviala et al., (2006) investigated the effects of strength training on functional capabilities and balance in middle-aged and older females. The authors reported that 21-weeks of strength training led to large increases in maximal and explosive strength of the leg extensors and in 10-metre walking time. This is in addition to improvements in dynamic balance test performance in both middle (52.8 +/- 2.4 years) and older (63.8 +/- 3.8 years) age groups. The benefits of resistance training are further supported by Kalapotharakos et al., (2005) who examined the effect of 12-weeks of heavy (80% of 1 RM) and moderate (60% of 1RM) on functional performance in healthy, inactive older age adults (60-74 years). Thirty-three subjects were randomly assigned to one of three groups; (1) control (CS, n = 10); (2) heavy resistance training (HRT, n = 11), or moderate resistance training (MRT, n = 12) and participated in 12 weeks of strength training, 3-times per week. Subjects performance measurements included 1RM lower-body strength, chair-rising time, walking velocity, stair-climbing time, and flexibility. The authors found significant differences between HRT and MRT for 1RM strength of the lower limbs after the 12-week training period. Functional performance improved comparably for both HRT and MRT after the training period.
​
Research has also suggested that muscular fitness may have a positive effect on cognitive performance and emotional health in older adults (Buse et al., 2008; Cassilhas et al., 2007). Busse et al., (2008) examined the effects of resistance training on cognitive performance and muscle strength in inactive elderly subjects with memory impairment. Thirty-one subjects with no dementia or depression were randomly assigned into two groups: (1) Resistance Exercise Group; and (2) Control Group. The resistance training exercise protocol lasted nine months and involved subjects performing three series of six exercises per session, for approximately one hour, twice a week. Busse and colleagues found that the resistance exercise group showed a significant increase in the Rivermead Behavioral Memory Test score (P = 0.021) and muscle strength (P < 0.001), with no significant difference in the other parameters evaluated. These results suggest that supervised resistance training can improve memory performance in inactive elderly individuals with previous memory impairments, besides increasing muscle strength.
Cassilhas et al., (2007) assessed the effect of moderate or high-intensity resistance training had on cognitive functions in 62 elderly subjects. Subjects were assigned to one of three groups; (1) Control; (2) moderate intensity; and (3) high intensity. Subjects were measured before and after on physical, hemodynamic, cognitive, and mood parameters. The authors found that both the resistance exercise groups improved significantly on the 1RM test compared to the control group (P <0.001). Subjects in the high-intensity group gained more lean mass (P = 0.05) than the control group and both resistance exercise groups performed better on the digit span forward (P < 0.05), Corsi's block-tapping task backwards (P < 0.05). Moderate- and high-intensity resistance exercise programs had equally significant effects on cognitive functioning on the following tests: Rey-Osterrieth complex figure immediate recall, Toulouse-Pieron concentration test errors, SF-36 (general health), POMS (tension-anxiety; depression-dejection; and total mood disorder).
Progressive Deterioration of the Musculoskeletal System
This reduction in muscle mass adversely affects a variety of metabolic risk factors, including obesity, dyslipidaemia, type 2 diabetes, and cardiovascular disease (Strasser and Schobersberger, 2010). Muscle tissue after the age of 30 declines at a rate of 3-to-8% per decade for individuals that do not engage in resistance training (Flack et al., 2011). By the age of 50 these inactive individuals, muscle mass decreases at an even faster rate of about 5-10% each decade. Nelson et al., (1994) estimated that by the age of 60 muscle mass loss for individuals that do not engage in resistance training is almost 0.5kg per year. This decline in muscle mass across the age ranges negatively affects a range of metabolic risk factors including cardiovascular disease, type 2 diabetes, obesity and dyslipidaemia (Strasser and Schobersberger, 2010).
​
At rest muscle tissue is extremely metabolically active, and this has a major influence on resting metabolic rate. Wolfe (2006) states that in untrained muscle, continuing protein breakdown and synthesis uses approximately 5-to-6-calories per pound of muscle every day. Subsequently, Keys and colleagues (1973) noted that the age-related decline in muscle mass has a direct association with the age-related degeneration in resting metabolic rate, which they estimated to be between 2-to-3% per decade in adults. In older adults around 65-to-75% of the calories used every day are attributed to resting metabolism, muscle loss and the ensuing metabolic reduction that is frequently accompanied by fat accumulation and gain (Wolfe, 2006).
​
Salvi and colleagues (2006) reported that approximately 80% of males and 20% of females over 60 years are either overweight or clinically obese. Scientific evidence has demonstrated that increased fat weight is related with an elevated risk of high blood pressure, adverse blood lipid profiles, type 2 diabetes and cardiovascular disease (Maggio and Pi-Sunyer, 2003; Wilson et al., 2002). Additionally, the ageing process is also linked with increased intra-abdominal fat deposits and according to Kohrt et al., (1993) is an independent risk for diabetes and cardiovascular disease. According to Flack et al., (2011) muscle loss may directly increase the risk of type 2 diabetes and cardiovascular disease. This is because muscle tissue is the primary site for both glucose and triglyceride removal. Boyle, (2010) estimated that by 2050 that one in three adults will have diabetes, therefore, it would be advisable for people to preserve as much muscle tissue as feasible during their older years.
Sarcopenia (muscle loss) is closely related to bone loss (osteopenia) and the ageing process due to the progressive deterioration of the musculoskeletal system. However, the degree of bone loss exceeds the degree of muscle loss. Marcell, (2003) estimated that up to 10% of muscle mass may be lost each decade, compared to an almost 30% decrease in bone (Kemmler et al., 2005; Warren et al., 2008). There are numerous challenges that occur due to musculoskeletal decline including carrying objects, rising from a seated position, walking, stair climbing and maintaining balance and posture (Warren et al., 2008; Holviala et al., 2006). One particular area of concern is the increased risk of failing as studies have suggested that the mortality and morbidity rates are higher in older adults who have fallen (Graafmans et al., 1996).
​
As discussed above there are numerous physical performance factors that are negatively affected by ageing, with the rate of decrease greater in some activities compared to others. This according to Klein, (2003) is due to the disproportionately higher rate of atrophy in fast-twitch (Type II) muscle fibres compared to slow-twitch (Type I) muscle fibres. As a result of this decline muscle power (more closely related with Type II than Type I muscle fibres) decreases at a greater rate than muscle strength (Häkkinen et al., 2001; Izquierdo et al., 1999; McKinnon et al., 2015). Equally, muscle endurance (more closely related with Type I than Type II muscle fibres), decreases at a slower rate than muscle strength (Frontera et al., 2008; Trappe et al., 2001). Therefore, while skeletal muscle enables movement and enhances many physiological functions in the body, muscle loss associated with ageing affects individuals to reduced health, fitness, and physical capabilities.
Cardiorespiratory System
​
The myocardium (heart), blood vessels, blood and the lungs collectively form the cardiorespiratory system (CRS). The ageing process adversely affects the CRS components and subsequently elevates the risk of cardiovascular disease. For example, maximal heart rate, stroke volume and cardiac output decrease gradually throughout the ageing process (Shephard, 1997). Furthermore, the left ventricle wall and arteries thicken, as well as a stiffening of the lungs which results in reduced aerobic capacity (Crapo, 1993). Fleg (1986) stated that age-related stiffening of the arterial tree results in increased systolic blood pressure, which may impose a greater load on the myocardium. As an adaptive mechanism to maintain normal wall stress, a modest age-associated concentric left ventricular hypertrophy develops (approximates 30% between 25-to-80 years). Aerobic exercise capacity decreases with age, although subjects who maintain a high level of physical activity, the decline appears to be approximately half of the 10% per decade decrease seen in inactive individuals. An age-related decline in maximal exercise heart rate has been a universal finding. However, some studies have found that cardiac output decreases with age, both at rest and during exercise, a recent study of subjects carefully screened to exclude latent coronary artery disease found no such decline in cardiac output. In these subjects, the age-related decline in maximal heart rate and systolic emptying at peak exercise was offset by increased utilisation of the Frank-Starling mechanism.
The prevalent risk factors for cardiovascular disease are increased resting blood pressure and adverse blood lipid profiles (high triglycerides, high total cholesterol, high low-density lipoprotein [LDL] cholesterol, or low high-density lipoprotein [HDL] cholesterol). Ong et al., (2007) estimated that nearly 35% of American adults, experience elevated blood pressure (hypertension), and almost 45% have blood lipid profiles outside suggested ranges (Lloyd-Jones et al., 2009). Although these coronary risk factors increase with age, there are exercise interventions that can reduce the probability of cardiovascular decline and disease.
Brain and Nervous System
​
Similar to other body systems, the brain and nervous system experience a continuing decline during the ageing process. Age-associated alterations in the brain and nervous system are accountable for various psychological and physiological performance difficulties in ageing adults, ranging from delayed response time to Alzheimer’s disease. Several mental health problems in this area arise including poor physical self-concept and self-esteem, general mood disturbance, depression, high tension and anxiety, and reduced cognitive abilities (Annesi and Westcott, 2004; 2007; Annesi et al., 2011).
​
Interestingly, O’Connor and colleagues (2010) reviewed a series of randomised controlled trials that examined whether strength training affects anxiety, chronic pain, cognition, depression, fatigue symptoms, self-esteem, and sleep. From a comparatively small body of evidence, the authors found that strength training was largely positive, and the weight of the available evidence supported the premise that strength training is associated with:
​
-
Reduction in anxiety symptoms among healthy adults.
​​
-
Reduction in pain intensity among patients with low back pain, osteoarthritis, and fibromyalgia.
​​
-
Improvements in cognition among older adults
​​
-
Reduction in symptoms of depression among patients with diagnosed depression or fibromyalgia.
​​
-
Reductions in fatigue symptoms.
​​
-
Improvements in self-esteem.
​​
-
Improvements in sleep quality among depressed older adults.
Several physical health issues affect the brain and the nervous system including chronic pain related to fibromyalgia, osteoarthritis and low back injuries that are associated with the ageing process (O’Connor, Herring and Caravalho, 2010). Additionally, there is a continuing decline in individuals motor skills and the ability to complete physical tasks due to nervous deterioration. These sensory input problems make it more difficult for older adults to perform physically active tasks and generalised exercise programs. For instance, the decline in eye functioning leads to impaired visual input that corresponds with less accurate eye-limb coordination (Guan and Wade, 2000). Additionally, the sensory mechanisms in the muscles also decline (muscle spindles) and in the joints (Golgi tendon organs) sensitive to movement force) (de Morais et al., 2013).
​
Exercise Guidelines for Older Adults
General recommendations for apparently healthy older adults include the inclusion of both aerobic (Table 1) and resistance training which is comparable to the guidelines set for the general adult population. The exercise professional should refer the client to a physician or health care professional if the client has or is at risk of developing medical or health conditions.
​
Aerobic Training for Older Adults
​
Westcott and Faigenbaum, (2012) suggest that older adults engage in large-muscle aerobic activity on most days of the week with each session lasting between 20-to-60 minutes at a training intensity between 60-to-90% of maximum (age-predicted) heart rate. Furthermore, the American College of Sports Medicine (ACSM, 2012; Riebe et al., 2015) recommends that aerobic exercise have two separate categories according to training intensity. The first category (individuals at high risk of CVD) undergoes a medical exam and diagnostic test before engaging in moderate-intensity training (40-to <60% VO2R or heart rate reserve; 3-to- <6 METs), e.g., walking). The second category (moderate risk for CVD) should undergo a medical examination before starting vigorous intensity training (≥60-to-90% VO2 or heart rate reserve, >6 METs, e.g., jogging or running).
​
Aerobic Training Frequency for Older Adults
The aerobic training frequency should be founded on a personalised client assessment as to how the suggested weekly exercise time is achieved in accordance with the client’s personal lifestyle. The recommended amount of aerobic exercise for moderate-intensity training category is between 150-to-300 minutes per week (2-to-5 hours), and the suggested training frequency is 5-days per week. For instance, a client can achieve the 150-minutes of weekly moderate-intensity aerobic activity by performing 30-minutes of walking on Monday, Wednesdays, Thursdays, Saturdays, and Sundays. The recommended amount of aerobic exercise for the vigorous-intensity training category is between 75-to-150 minutes per week and the suggested training frequency is 3-days per week. For example, 90 minutes of weekly vigorous intensity aerobic activity could be attained by doing 30 minutes of jogging on a Tuesday, Thursday, and Saturday.
​
Aerobic Training Intensity for Older Adults
​
Guidelines for aerobic training intensity have previously been founded on exercise heart rate. However, in older adults’ considerations need to be made due to the large differences in maximal heart rate. Additionally, this population group are more likely to be prescribed medications that affect their heart rate response to exercise and physical activity. This has led to the current guidelines to be established on the client’s perceived physical exertion levels during the exercise session. On the new Borg or R.P.E scale, it is recommended that individuals who perform moderate-intensity training do so at a physical exertion level of 5-to-6. Clients performing vigorous-intensity training should perform the exercise session at a perceived physical exertion level of 7-to-8.
​
Aerobic Training Duration for Older Adults
The recommendations for aerobic training duration are prescribed in minutes per day. This training duration can also be separated into smaller parts for moderate-intensity exercise to accommodate the client’s daily schedule. For older clients in the moderate-intensity training category, the suggested daily duration is a >30 minutes, which may be accumulated in exercise sessions of >10 minutes each. For clients in the vigorous-intensity training category, the suggested daily session is >20 minutes. This should be completed in a single exercise session. A mixture of moderate-intensity and vigorous-intensity aerobic training may also be performed if the client follows the particular training durations.
​
Modes of Aerobic Activities for Older Adults
​
Aerobic exercise may be more beneficial for the older client if they performed rhythmic activities that engaged large muscles for >20 minutes at a vigorous intensity or >30 minutes at a moderate-intensity exercise. Older clients that have difficulties performing weight or load-bearing activities may perform weight-supported aerobic exercises (i.e., recumbent cycling, upright cycling, rowing or swimming). Additionally, older adults who are physically capable of performing weight-bearing exercises can perform a range of ambulatory activities (i.e., walking, jogging, running, stepping or elliptical training).
Table 1. Aerobic Endurance Training Guidelines for Older Adults.
Resistance Training Guidelines for Older Adults
Resistance Training
Established resistance training recommendations from Westcott and Faigenbauum, (2012) call for a range of both single-joint exercises and multiple-joint exercises that involve the major muscle groups. According to these recommendations, older adults should complete 2-to-3 resistance training sessions per week on separate days.
Westcott and Faigenbauum, (2012) present a relatively large resistance loading range of between 60-to-90% 1RM they also suggest that older clients perform 10-to-15 repetitions of each exercise initially. The authors further note that progression in loading can occur by almost 5% whenever 15 repetitions are achieved by the client. It is also suggested that from strength development that older adults perform controlled resistance movements as a tempo rate of between 4-to-6 seconds per repetition with a full range of movement (Table 2).
​
Resistance Training Frequency for Older Adults
​
Research on resistance training and older adults suggest that this population group responds differently with regards to exercise frequency. For instance, Hunter et al., (2013) examined the effects of three different training frequencies of combined resistance and aerobic training on total energy expenditure and activity-related energy expenditure in older females. Seventy-two females (60-to-74 years old) were randomly assigned to the following groups: (1) 1 day/week of aerobic and 1 day/week of resistance (1+1); (2) 2 days/week of aerobic and 2 days/week resistance (2+2); or (3) 3 days/week aerobic and 3 days/week resistance (3+3). All groups increased fat-free mass, strength and aerobic fitness and decreased fat mass. No significant changes were observed in cytokines or perceptions of fatigue/depression. No time by group interaction was found for any fitness/body composition variable. TEE and AEE increased with the 2+2 group but not with the other two groups. Non-exercise training AEE (NEAT) increased significantly in the 2+2 group (+200 kcal/day), group 1×1 showed a drift for an increase (+68 kcal/day) and group 3+3 decreased significantly (−150 kcal/day). The authors concluded that 3+3 training may inhibit NEAT by being too time consuming and does not induce superior training adaptations to 1+1 and 2+2 training.
​
Conversely, Westcott et al., (2009) applied the ACSM protocols for exercise type, intensity, and duration across 3 training frequencies. Males and female subjects aged between 21-to-80 years participated in a 10-week combined strength and aerobic activity program. Across all training frequencies (1, 2, or 3 sessions per week), mean changes included a reduction in body fat of 1.97%, a decrease in fat weight of 1.7 kg, an increase in lean weight of 1.35 kg, a reduction in systolic blood pressure of 3.83 mm Hg, and a reduction in diastolic blood pressure of 1.73 mmHg. More frequent weekly training sessions were associated with greater improvements in body fat percentage, fat weight, and lean weight. This is supported by DeMichele et al., (1997) who examined training frequency effects on torso rotation muscle strength. Fifty-eight male (age 30 ± 11yrs) and 25 females (age 28 ± l0yrs) with no history of low back pain participated in this study. Subjects isometric (IM) torso rotation strength was measured before (T1) and after (T2) 12-weeks of training. DeMichele and associates reported that the 1 day per week group did not increase IM torso rotation strength compared to the control group at any angle. Both the 2 and 3 days per week groups increased their IM torso rotation strength compared to the control group at all but one angle. There were no significant differences in IM torso rotation strength between the groups that trained 2 or 3 days per week. During the training period, the 2 and 3 days per week groups increased their dynamic training load significantly more than the 1 ×/wk group.
​
It has been recommended by established health and fitness organisations (ACSM and NSCA) that older adults schedule resistance training sessions on two or three non-consecutive days each week if develop muscular strength is a primary goal. However, more evidence is needed to fully establish specific training frequencies as attempting to apply training frequencies from different population age ranges is similar to comparing apples to oranges.
Sets (Volume)
​
There have been several major reviews that have compared the effects of various sets on strength development on several population groups. For example, Carpinelli and Otto (1998) reported that one-set of resistance exercise is as effective as multiple-sets for increasing muscle strength and hypertrophy. In contrast, a meta-analysis by Rhea et al., (150) specified that two-sets were more effective than one-set, that three exercise sets were more effective than two exercise sets, and that four exercise sets were more effective than three exercise sets. They determined that multiple-set training was more beneficial than one-set training and that four-sets per muscle group elicited the greatest strength gains. Krieger’s (108) meta-regression also reported that multiple- set training is more effective than single-set training. His analyses displayed similar effects from performing one-set per exercise and four-sets per exercise and similar effects from performing two-sets per exercise and three-sets per exercise, which produced greater strength gains than single-set training.
​
However, Eichman and GieBing (2013) reported that one high-intensity exercise set was superior to three-sets of each exercise to improve muscle mass and strength. In this study (n=43) subjects trained twice a week for ten-weeks with one group performing high-intensity training (n=16) and one drop-set of each exercise to the point of momentary muscular failure (HIT). The other group (n=14) performed as many repetitions as possible in each set and performed three sets of each exercise (3ST). The control group (n=13) did not strength train at all. The body composition of all groups was analysed in weeks 0 and 11. Strength tests and bioelectrical impedance analysis displayed increased strength and muscle mass in both training groups but not in the control group. However, both strength and muscle mass increased to a greater extent in HIT than in 3ST. After ten weeks of training, HIT increased the maximum number of repetitions in the nine-test exercise by a mean of 25 (15.7/40.3) repetitions per exercise while 3ST increased repetitions by an average of only 15 (6.4/24) repetitions per exercise. Furthermore, HIT increased to a significantly greater extent than 3ST while decreasing body fat.
​
Baechle and Westcott (2010) have logically suggested that previously untrained older adults start with one-set of each exercise. As the client increases in confidence and enthusiasm for resistance exercise, then the fitness professional may consider increasing the training volume by progressively transitioning to ≥ two sets of selected exercises. Older adults should have an inter-set recovery period of between 2-to-3 minutes training bout to enable muscle recovery and energy replenishment before each exercise set (Miranda et al., 2007).
Repetitions (Intensity) and Resistance Loading
​
There is an inverse relationship between the resistance loading used for an exercise and the number of repetitions that can be completed. For instance, the greater the loading the client lifts the fewer repetitions they can achieve. Several studies have reported favourable and significant adaptations in older adults that incorporated a repetition range of 8-to-12 repetitions with a loading that produced temporary muscle fatigue.
​
For example, Frontera and associates (1985) investigated the effects of strength training on muscle function and mass in older males. Twelve healthy untrained subjects (age range 60-to-72 yr.) participated in a 12-week strength training program (8 reps per set; 3 sets per day; 3 days per week) at 80% 1RM for extensors and flexors of both knee joints. By week 12 the subject’s extensor and flexor strength had increased by 107.4 (P <0.0001) and 226.7% (P <0.0001), respectively. Isokinetic peak torque of extensors and flexors increased by 10.0% and 18.5% (P <0.05) at 60 degrees/s and 16.7 and 14.7% (P <0.05) at 240 degrees/s. Midthigh composition displayed an increase (P <0.01) in total thigh area (4.8%), total muscle area (11.4%), and quadriceps area (9.3%). Biopsies of the vastus lateralis muscle revealed similar increases (P <0.001) in type I fibre area (33.5%) and type II fibre area (27.6%). This is supported by the previously discussed study by Westcott et al., (2009) applied the ACSM protocols for exercise type, intensity, and duration across 3 training frequencies.
​
Taaffe et al., (1996) examined the effects of 52 weeks resistance training at one of two exercise intensities (80% 1RM vs. 40% 1RM) on thigh muscle strength, fibre CSA, and tissue composition in healthy 65-79-year-old females. Subjects were assigned a control (CO), high-intensity (HI) or low-intensity (LO) training group. Exercise protocols consisted of three sets of leg press, knee extension, and knee flexion exercises, 3 days per week, at either 80% of one-repetition maximum (1-RM) for 7 repetitions (HI) or 40% of 1-RM for 14 repetitions (LO). Muscle strength was assessed by 1-RM, thigh lean tissue mass (LTM), fat mass, and bone mineral, and fibre CSA of vastus lateralis muscle. Results showed that muscle strength increased significantly compared to control both HI (59.4 +/- 7.9%) and LO (41.5 +/- 7.9%) increased significantly (p = 0.001). Type I fibre CSA increased over time (P < 0.05) in both HI and LO exercise groups, with a trend for increased type II area (HI, P = 0.06; LO, P = 0.11). Both training protocols produced significant gains in thigh muscle strength, which were associated with fibre hypertrophy, although these did not translate into significant alterations in thigh tissue composition.
Harris et al., (2004) examined the effects of training intensity on strength gains in older adults over 18-weeks using non-periodised, progressive resistance-training protocols. Sixty-one male and female subjects volunteered for this study and were separated into 4 groups: Group 1 (n = 17, 71.4 +/- 4.6 years) performed 2 sets of 15RM, group 2 (n = 13, 71.5 +/- 5.2 years) performed 3 sets of 9RM, group 3 (n = 17, 69.4 +/- 4.4 years) performed 4 sets of 6RM, group 4 (n = 14, 72.3 +/- 5.9 years) served as controls. Training groups exercised 2 days per week performing 8 resistance exercises. Excluding for training intensity, the acute program variables were equated between groups. A 1RM for 8 exercises was obtained every 6 weeks. By weeks 12 and 18, all training groups were significantly stronger than controls (p < 0.01). However, no difference existed between groups 1, 2, and 3 at any time. The data suggests that, for protocols with equated acute program variables, strength gain is similar over 18 weeks for training intensities ranging from 6 to 15 RM in previously untrained older adults. When programming non-periodized, progressive resistance exercise for novice senior lifters, in the initial phases of the program, a wide range of intensities may be employed with similar strength gain.
​
Chestnut and Docherty (2009) compared the strength, cross-sectional area, specific tension, and anthropometric changes elicited by 4RM and 10RM resistance training protocols in 24 untrained subjects. Subjects were randomised to either the 4RM or the 10RM group. Subjects trained with free weights 3 times per week for 10 weeks. The 4RM group performed 6 sets of 4 repetitions to failure and the 10RM group performed 3 sets of 10 repetitions to failure. Strength (1RM) was measured at 0, 6, and 10 weeks and muscle cross-sectional area, specific tension, and relaxed-and flexed-arm girth were measured at 0 and 10 weeks. The results showed significant (p < 0.05) increases in subjects forearm extensor and flexor 1RM strength, muscle cross-sectional area, specific tension, and flexed-arm girth in both groups. The 4RM and 10RM loading intensities elicited significant and equal increases in strength, cross-sectional area, specific tension, and flexed girth. These results suggest that 4RM and 10RM resistance-training protocols equated for volume produce similar neuromuscular adaptations over 10 weeks in previously untrained subjects.
​
Wescott and Faigenbaum (2012) have logically suggested that older adults without prior experience in resistance training begin with 10 to 15 repetitions at low intensities (i.e., 40-to-60% 1RM). As the older client becomes familiar with resistance training, they may progress to 10-to-15 reps at 60-to-70% 1RM. When this exercise protocol becomes habitual, older adults may train safely and effectively with higher-intensity resistance and repetition protocols, (i.e., 8-to-12 reps with 70-to-80% 1RM, and even 4-to-8 reps at 80-to-90% 1RM).
​
Movement Speed During Resistance Training
​
It has been suggested that muscular strength development is best achieved with relatively heavy resistance at a controlled movement speed. Munn et al., (2005) investigated and compared the effects on strength in the initial phase of resistance training with one or three sets and fast (140 degrees.s(-1)) or slow speeds (50 degrees.s(-1)). Untrained subjects (n = 115) were randomly assigned to a control group or one of four training groups: one set fast; three sets fast one set slow; or three sets slow. All subjects trained 3 sessions per week for 6 weeks with the resistance training groups performing 6- to-8RM unilateral elbow flexion contractions. Control subjects did not engage in any form of training. Subjects 1RM maximum strength, arm circumference, and biceps skinfold thickness were measured before and after training protocols. The results showed that one slow set significantly increased strength by 25% (p < 0.001), whereas three sets of training produced significantly greater increases in strength than one set (difference = 23% of initial strength, P < 0.001) and fast training resulted in a significant greater increase in strength than slow training (difference = 11% P = 0.046). The interaction between sets and speed was negative (-15%) and of borderline significance (P = 0.052), suggesting there is a benefit of training with three sets or fast speeds, but there is not an additive benefit of training with both. Munn and associates concluded that three sets of exercise produce twice the strength increase of one set in the early phase of resistance training. Training fast produces greater strength increases than training slow; however, there does not appear to be any additional benefit of training with both three sets and fast contractions.
It has been suggested that to develop muscular power it may be best to perform resistance exercises with moderate resistance at fast movement speeds (Wilson et al., 1993). Older adults training for increased muscle strength may attain better results by lifting loads greater than 60% of maximum at controlled movement speeds, whereas those training for muscle power may attain better results by lifting loads less than 60% of maximum at faster movement speeds. However, most studies have been completed with regards to athletic performance and it is questionable how these training effects can be validated in this population group. That’s said, it is logical to suggest that older adults should begin exercising with a resistance training program that seeks to increase muscular strength and then progresses to include power training protocols. Caserotti et al., (2008) has shown that explosive-type heavy-resistance training (power training) may be a safe mode of training in healthy women even in the eighth decade of life. Importantly, Caserottis and colleagues showed that power training produces adaptive neuromuscular changes that are frequently connected with the risk of falls and disability in aged individuals.
Breathing
​
An important aspect that is often overlooked is the breathing actions and mechanics when older adults perform resistance training. Irrespective of the exercise intensity, older adults should refrain from holding their breath when engaged in resistance training. Breath-holding also known as the Valsalva manoeuvre, increases internal pressure to levels that can inhibit venous blood flow, elevate blood pressure, and may cause adverse sensations including light-headedness or blackouts (Graham, 2012). The commonly accepted breathing procedure for older adults during resistance training is to exhale throughout each concentric muscle action and to inhale throughout each eccentric muscle action (Baechle and Westcott, 2010).
​
Resistance Training Progression
​
The central premise for individuals to consider when endeavouring to develop muscle strength, size, and function is to systematically stress the skeletal muscles via progressive resistance training. This can be achieved (to some degree) with bodyweight exercises, external resistance (i.e., elastic bands, free or machine weights). These modes of exercise will enable the older adult to progressively increase the exercise resistance as the muscle adapts to the imposed stressor. When the resistance training is progressively increased within a prescribed loading (repetition) range of 6-to-15 repetitions significant results in strength have been shown in older adults. Importantly, whatever repetition range is prescribed for the client correct technique and form should be maintained throughout the whole movement. Once the older client is ready to progress then the resistance should be raised by approximately 5% (Westcott and Faigenbaum, 2012).
Table 2. NSCA Resistance Training Recommendations for Older Adults
