The Effects of Resistance Training and Walking on ... - SAGE Journals

JOURNAL 10.1177/0898264305281102 Simons, Andel OF /AGING EXERCISE AND AND HEALFUNCTION TH / February AL2006 FITNESS

The Effects of Resistance Training and Walking on Functional Fitness in Advanced Old Age ROBERT SIMONS Bonsai Spa & Wellness Clinic, Largo, Florida

ROSS ANDEL University of South Florida, Tampa, Florida

The authors assessed the effects of resistance training and walking exercise on measures of functional fitness. Sixty-four volunteers (average age 83.5 years) from an independent-living facility were randomly assigned to walking, resistance training, or control groups. Participants in the walking and resistance-training groups engaged in two exercise sessions per week for 16 weeks. Measures of functional fitness included upper and lower body strength, hip and shoulder flexibility, agility and balance, coordination, blood pressure, and resting heart rate. Repeated measures analysis of variance was used to examine pretest to posttest differences. Both exercise groups showed significant improvements relative to control group in upper and lower body strength, shoulder flexibility, and agility and balance exercise. Findings demonstrate that exercise can lead to improvements in multiple domains of functional fitness even among very old, previously sedentary individuals, possibly making activities of daily living easier to perform. Keywords:

resistance training; walking; functional fitness; older adults

Inevitably, age leads to some functional decline and greater likelihood of difficulties in performing activities of daily living. Functional decline in older adults appears to be influenced by levels of physical activity (e.g., Hubert, Bloch, Oehlert, & Fries, 2002). Review studies AUTHORS’ NOTE: Many thanks to William Haley for his helpful comments on an earlier version of this manuscript. For further information contact: Ross Andel, University of South Florida, School of Aging Studies MHC 1321, 4202 E. Fowler Ave, Tampa, FL 33620. Phone: 813-974-9743, Fax: 813-974-9754, E-mail: [email protected] JOURNAL OF AGING AND HEALTH, Vol. 18 No. 1, February 2006 91-105 DOI: 10.1177/0898264305281102 © 2006 Sage Publications

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indicate that physical inactivity is related to accelerated depletion of functional reserves and deficits in muscle strength and neuromuscular activation, leading to increased incidence of functional problems, frailty, and falls (King, Rejeski, & Buchner, 1998; Mazzeo & Tanaka, 2001; Van der Bij, Laurant, & Wensing, 2002; Spiraduso, 1995). At the same time, sedentary lifestyle is still common among older adults and appears to increase with advancing age. According to the Third National Health and Nutrition Examination Survey (Christmas & Andersen, 2000), physical inactivity rates among American adults average 26% for ages 45 to 64, 27% at ages 65 to 74, and 46% at ages older than 75 years. Growing evidence supports the notion that physical activity can offset age-related functional decline and preserve independence longer into old age. For example, the positive effect of walking on health has been recognized for centuries. Hippocrates wrote around 400 B.C. that “Walking is man’s best medicine” (Spiraduso, 1995, p. 17). Recent scientific studies provide evidence that walking can improve functional health in old age (Brown & Holloszy, 1993; Hamdorf & Penhall, 1999; Wong, Wong, Pang, Azizah, & Dass, 2003). Resistance training has also gained attention as a strategy to support functional health in older adults (e.g., Brandon, Boyette, Lloyd, & Gaasch, 2004; Campbell, Crim, Young, & Evans, 1994; Fiatarone et al., 1994). Age-related decrements in muscle strength, power, and flexibility occur naturally across middle and older adulthood (e.g., Hurley & Hagberg, 1998). For example, strength is estimated to decrease by 40% to 50% between 25 and 80 years of age (American College of Sports Medicine, 1998). In the Framingham study, 40% of women between the ages of 55 and 64, 45% of women aged 65 and 74, and 65% of women between 75 and 84 years of age were unable to lift 10 pounds (Jette & Branch, 1981). Many of the same women also reported having difficulties with performing normal household work. Musculoskeletal deficits are being recognized as an important underlying cause of the onset of frailty and increased incidence of falls with age (e.g., Fiatarone & Evans, 1993; Hurley & Hagberg, 1998) as well as difficulties performing daily and leisure activities such as carrying grocery bags, cooking, gardening, and traveling (Spiraduso, 1995). Exercise programs appear to support muscular, functional, and cardiovascular health. Intervention studies with older adults report

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measurable gains in muscle mass and strength following resistancetraining programs (Akima et al., 2001; Cavani, Mier, Musto, & Tummers, 2002; Fiatarone et al., 1990). Others found exercise-related increase in balance, agility, and flexibility (Cavani et al., 2002) and neuromuscular function (Hakkinen & Hakkinen, 1995; Taaffe, Duret, Wheeler, & Marcus, 1999) as well as reduced incidence of falls (Buchner et al., 1997; Province et al., 1995). Finally, moderate exercise may support cardiovascular function in older adults (Myers, 2003). Increasing attention has been paid to the role of exercise in health promotion in old age. However, still little is known about benefits of exercise among sedentary individuals in advanced old age although older adults older than 80 years of age are the fastest growing segment of the population (U.S. Bureau of the Census, 1996) and have a higher likelihood of living a sedentary life than younger cohorts (Christmas & Andersen, 2000). This study explored the effects of 16 weeks of resistance training and walking exercise on measures of functional and cardiovascular fitness in a sample of adults in advanced old age who were sedentary prior to the study and lived independently in a community. The goal was to assess the effects of the two types of exercise on multiple measures of functional fitness, namely, upper and lower body strength, flexibility, agility and dynamic balance, coordination, and cardiovascular fitness. A secondary goal was to explore feasibility and usefulness of walking and resistance training among these individuals. We hypothesized that both training groups would outperform the control group on the examined measures of functional fitness. We also expected that the training groups would be able to adhere to their exercise routines for the duration of the study. Method PARTICIPANTS

The study included 64 residents (45 women, 19 men) from an independent living facility. This type of facility provides meal and activity services for the residents but typically does not assist with activities of

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daily living. Potential volunteers were recruited through community paper and newspaper advertisements, announcements in the community, and a study presentation. The inclusion criteria were (a) clearance to participate in an exercise program by the primary physician, (b) lack of regular (2 to 3 times a week) engagement in strenuous physical activity for at least 1 year prior to the study, and (c) being at least 65 years of age at the time of study initiation. In addition, the participants were ambulatory, nonhypertensive, nondiabetic, and nondemented. All participants were Caucasian. The study was approved by the Institutional Review Board at the University of South Florida. Several participants in each group used canes, walkers, and electrical transports for safety and convenience but were able to perform their prescribed exercise routines. Participants were on average 83.5 years of age (SD = 6.2, range 66 to 96 years). Only five participants were less than 75 years of age. Women accounted for 73% of the sample. Participants were randomly assigned to one of two exercise groups or a control group. Twenty-one participants (15 women, 6 men) were assigned to the resistance-training program, 18 participants (11 women, 7 men) were assigned to the walking program, and 21 participants (18 women, 3 men) were assigned to the control group. Participants were informed that the intervention programs would be made available to all participants on the completion of the study. Four participants dropped out during the course of the study, 2 for nonstudy related illnesses and 2 for personal reasons. Of these 4 participants, 1 was from the walking group, 2 were from the resistance-training group, and 1 was from the control group. PROCEDURES

All participants regardless of group assignment completed a pretest and posttest that consisted of measures of functional fitness including upper and lower body muscle strength, joint flexibility, agility and balance, coordination, and cardiovascular health. Participants in the resistance-training group and the walking group also completed two exercise sessions per week for a period of 16 weeks. All participants were encouraged to attend a series of six 1-hour health lectures that were given at approximately 3-week intervals


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throughout the 16-week intervention by one of the authors. The lecture topics were aging in the 21st century, senior fitness program development, balance and stability training, aging and the mind, aging and nutrition—Part 1, aging and nutrition—Part 2. PRETEST AND POSTTEST ASSESSMENTS

All pretest and posttest measures were administered by trained instructors who were selected for this part of the study from the Fountains Fountain of Youth Fitness Center or Simons Fitness Enterprises personal training staff. These instructors were blind to the intervention status. We assessed muscle strength using a manual developed by the American Alliance for Health Physical Education, Recreation, and Dance (AAHPERD; Osness, 1990)—Functional Fitness Assessment for Adults Over 60. The 24-hour test-retest reliability of the measures was assessed by several studies and was .80 or higher, with most values more than .90 (see Osness, 1990, pp. 21, 22). In agreement with the AAHPERD manual, participants were tested for lower and upper body muscle strength using one-repetition maximum (1-RM) method where participants are asked to perform one full-strength repetition of a particular exercise two or three times, following a short warm-up. The highest value was recorded. Strength. Lower body strength was measured as total pounds from the 1-RM on leg extensions, leg curl, and leg press machines. Leg extensions and leg press reflect quadriceps strength and leg curls reflect hamstring strength. Upper body strength was measured as total pounds from the 1-RM on lat pull-down, upper back, and chest press machines. Lat pull-down targets latissimus dorsi, one of the major back muscles. The upper back exercise resembles a rowing motion but with no leg movement, targeting deltoid and scapular muscles. Chest (or bench) press targets chest muscles, particularly the pectoralis major, as well as triceps and deltoid muscles. All testing repetitions were initially demonstrated and performed with strict adherence to proper form (slow movement and full range of motion) for both testing accuracy and safety.

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Flexibility. To measure general flexibility, we used the Sit-AndReach test from the AAHPERD manual. During this test, the participant sits on the floor with the knees extended and reaches as far forward as possible. Distance reached was assessed in inches. Joint flexibility was further assessed with a mechanical goniometer at the shoulder joint and the hip joint as degrees of movement. Shoulder flexibility was a composite of scores attained on shoulder abduction and shoulder flexion. We measured shoulder abduction and shoulder flexion from the side position (arm vertical) to the highest point attained without torso movement. Hip flexibility was measured as maximum hip flexion. Participants performed hip flexion from the supine position (thigh horizontal) to the highest point attained with knee bent. All flexibility assessments were taken on the right side of the body. Eye-hand coordination. We used the Soda-Pop test from the AAHPERD manual. While seated, participants were timed as they grasped, turned upside down, and replaced three unopened soda cans that are 5 inches apart. The better time (in seconds) from two trials was recorded. Agility and balance. We used the Agility and Dynamic Balance test from the AAHPERD manual. The score was calculated as total time (in seconds) needed to repeatedly stand up from an armless chair, negotiate a short obstacle course made from three cones, sit down, and lift the feet. Two cones were placed five feet to either side of the chair and six feet behind the chair. Cardiovascular health. We assessed resting heart rate (number of beats per minute) and systolic and diastolic blood pressure. Participants were allowed a minimum of 10 min of rest. Readings were taken in a seated position. INTERVENTION

Trained instructors from the Fountains Fountain of Youth Fitness Center or Simons Fitness Enterprises personal training staff were


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selected to provide supervision for the intervention part of the study. Prior to each intervention session, participants were supervised through a warm-up routine that included neck rotations, volume breathing, triceps stretch (i.e., one hand at a time behind the back), shoulder turn (i.e., reach behind the shoulder blade), two-legged rock, a hamstring stretch, and a knees-to-chest stretch. Resistance-training program. As part of the warm-up, participants were allowed and encouraged to perform several repetitions, with no resistance on each machine to reduce the risk of injury. The initial weight per exercise machine, representing pounds of resistance, was set at 75% of the individual’s 1-RM from the initial assessment (pretest). Each workout consisted of six strength exercises performed on six Keiser machines: leg extensions, leg curls, leg press, lat pull-down, rowing movement, and chest press. Each exercise was performed for one set of 10 repetitions. When 10 repetitions were completed with proper exercise form for three to five consecutive workouts the weight load was increased by 5%. A proper exercise form was defined as relatively slow movement and full range of motion. All training repetitions were performed in approximately 7 s, with 2 s for each lifting movement (concentric muscle action), 4 s for each lowering movement (eccentric muscle action), and a 1 s pause at full muscle contraction to avoid momentum as a factor. All training repetitions were executed through the full range of joint movement as determined by the participant’s functional ability and freedom from discomfort. The duration of the training sessions varied across participants but averaged between 15 and 20 min of overall duration and 6 min of muscle activity, as each of the six training exercises required about 1 min of muscle activity. The trained instructors initially assisted participants getting on and off the machines, setting the seat positions, and designating the weight at the appropriate resistance level. They also provided participants with encouragement, feedback, and reinforcement throughout the workout. Some participants, after a period of time, were paired up to perform the exercise circuit with someone of similar abilities. However, all participants were supervised throughout the duration of the study, especially for periodic resistance increases.

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Walking program. The walking program consisted of two walking sessions per week during the period of 16 weeks. The initial walk length and pace were determined at the beginning of the study based on a preassessment performance during a timed, 880-yard walk. Participants were monitored individually and encouraged to gradually increase the distance of their walks and reduce the elapsed time. However, the walks were self-paced and no maximum time was set to complete the exercise. An outdoor walk course and an indoor inclement weather course were designated. Participants performed their walks on the same day at the same time to enhance exercise adherence and lessen the supervisory task. All walks were supervised and recorded, and participants were encouraged to increase pace and distance walked. ANALYSES

We used paired t tests to calculate within-group pretest-to-posttest differences. Given the number of comparisons performed, these analyses should only be considered exploratory. We used one-way analysis of variance (ANOVA) to test between-group differences in age and baseline (pretest) scores. To explore differences in performance on functional fitness measures attributable to intervention, we performed separate pairwise comparisons within a 2(group: walking or resistance training vs. control) × 2(test: pretest vs. posttest) mixed-design repeated measures analyses of variance (RM-ANOVA). The first factor was betweengroups and the second factor was within-groups. Comparing each exercise group separately against the control group allowed the most direct examination of our main hypothesis—to explore the effects of any exercise on functional measures—and reduced the chances of committing Type II error because of the relatively small sample size. Similar pairwise comparisons were performed, for example, by Brandon et al. (2004), Buchner et al. (1997), and Fiatarone et al. (1994) in studies similar to ours. We used the procedure general linear model (GLM) for unbalanced designs from the SAS statistical software package (SAS Institute,


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1999a) for one-way and repeated measures ANOVAs. This procedure calculates a general linear model and is preferred over SAS procedure ANOVA for its ability to account for differences in sample size across treatment groups (SAS Institute, 1999b). The main goal of these analyses was to test the statistical significance of the group-by-test interaction. When group-by-test interaction was significant, the post hoc Tukey’s test of honestly significant differences was used to explore the direction of the differences identified by the significant interaction. The level of statistical significance was set at a two-tailed .05 level in all analyses. This level was automatically adjusted by the Tukey’s test for comparison-wise Type I error. To avoid multiple comparisons within the same domain in the main analyses, we used composite measures of upper body strength (sum of lat pull-down, chest press, and upper back), lower body strength (sum of leg extensions, leg curl, and leg press), and shoulder flexibility (sum of shoulder flexion and shoulder adduction). We used z scores to account for variations in score ranges across these measures. Variables within each composite were highly correlated (r = .78 or higher). Results The average age was 81.6 years (SD = 3.3) in the walking group, 84.6 years (SD = 4.5) in the resistance-training group, and 84.0 years (SD = 3.3) in the control group. One-way ANOVA yielded no significant between-group differences in age. Mean scores, standard deviations, and within-group pretest to posttest comparisons for all functional fitness measures are presented in Table 1. There were no significant differences in pretest performance across the three groups. Overall, paired sample t tests indicated that participants in the walking and resistance-training groups performed better at posttest compared to pretest on all functional measures and had lower systolic blood pressure at posttest. The control group improved in lat pull-down and coordination and worsened in shoulder adduction and agility and balance. The results from 2(group) × 2(test) RM-ANOVAs follow.

100 17.5 11.4 21.1 21.6 16.3 63.5 5.4 10.2 14.2 16.0 22.0 2.5 12 6 8

37.5 51.7 176.1 18.6 103.2 138.8 143.7 49.2 14.9 133 68 76

SD

50.8 28.1 45.0

M

SD

128* 70 76

149.5*** 150.7*** 44.8** 12.8**

47.1*** 62.3*** 191.4*** 20.2* 116.4***

9 4 6

12.6 15.2 21.6 2.8

22.7 18.7 66.8 5.0 14.2

61.1** 20.2 37.2** 12.5 54.2*** 21.7

M

Posttest

133 70 75

142.0 144.4 50.8 15.1

29.8 45.2 183.8 17.9 102.7

55.2 32.1 48.1

M

13 9 6

10.0 10.0 22.4 2.7

20.3 19.1 81.9 3.6 6.4

20.0 16.2 17.7

SD

Pretest SD

124* 68 75

11 6 6

151.9*** 10.8 153.0*** 10.2 41.4* 12.5 12.7*** 2.3

48.3*** 23.0 61.2*** 19.4 214.3*** 73.9 19.5*** 3.8 107.5*** 7.8

65.5*** 22.1 41.6*** 17.7 55.9*** 21.5

M

Posttest

Resistance Training

Note. Paired sample t test statistic was used to calculate pretest to posttest differences in performance. *p < .05. **p < .01. ***p < .001.

Upper body strength (pounds) Lat pull-down Chest press Upper back Lower body strength (pounds) Leg extensions Leg curl Leg press Flexibility test (inches) Hip flexion (degrees) Upper body flexibility (degrees) Shoulder flexion Shoulder adduction Agility and balance (seconds) Coordination (seconds) Blood pressure (mm Hg) Systolic blood pressure Diastolic blood pressure Resting heart rate (beats/min)

Variable

Pretest

Walking

Table 1 Means and Standard Deviations for Measures of Functional Fitness

128 68 73

146.9 152.0 50.3 15.6

30.0 39.0 138.8 19.3 103.1

46.9 30.0 42.9

M

9 8 5

15.9 13.9 16.5 2.9

17.2 17.2 66.9 5.3 22.1

16.5 12.6 14.7

SD

Pretest

M

129 70 77

140.8 138.4* 58.7** 13.5**

31.7 44.0 139.5 18.5 101.0

12 5 12

30.7 31.2 16.9 3.4

14.1 16.2 68.5 4.2 20.7

18.9 16.8 14.2

SD

Posttest

51.7* 30.0 42.1

Control


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WALKING GROUP VERSUS CONTROL GROUP

The RM-ANOVAs yielded a significant group-by-test interactions for upper body strength (F[1, 38] = 11.68, p < .01), lower body strength (F[1, 38] = 4.54, p < .05), shoulder flexibility (F[1, 38] = 12.41, p < .01), hip flexibility (F[1, 38] = 5.61, p < .05), and agility and balance (F[1, 38] = 18.46, p < .001). The post hoc Tukey’s test comparisons indicated that all significant interactions reflected a performance gain of the walking group over the control group between pretest and posttest. The most substantial performance gains within the walking group were in upper body strength (20%), coordination (14%), lower body strength (12%), and hip flexibility (11%) (see Figure 1). RESISTANCE TRAINING GROUP VERSES CONTROL GROUP

The analyses yielded significant group-by-test interactions for upper body strength (F[1, 41] = 9.85, p < .01), lower body strength (F[1, 41] = 25.17, p < .001), shoulder flexibility (F[1, 41] = 14.29, p < .01), agility and balance (F[1, 41] = 17.84, p < .001), and systolic blood pressure (F[1, 41] = 4.32, p < .05), and a marginally significant result for resting heart rate (F[1, 41] = 3.87, p = .06). Tukey’s tests revealed that all results reflected an improvement in the resistancetraining group over the control group. The most substantial performance gains within the resistance-training group were observed in the lower body strength (20%), agility and balance (20%), upper body strength (17%), and coordination (16%) (see Figure 1). Discussion The goal of this study was to examine the effects of walking and resistance-training exercise on multiple measures of functional fitness among individuals in advanced old age who were sedentary prior to the intervention. The main finding was that both types of exercise led to functional improvement in multiple domains relative to a control group. These findings provide further evidence for the benefits of exercise in advanced old age found previously (Fiatarone et al., 1994). Although our sample included participants with age range

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20 Walking 15 Resistance training

% improvement

10

Control

5 0 (5) (10) (15)

Resting heart rate

Diastolic blood pressure

Systolic blood pressure

Coordination

Agility/balance

Hip flexibility

Shoulder flexibility

Lower body strength

Upper body strength

(20)

Figure 1. Average pretest to posttest improvement on measures of functional fitness in the walking, resistance training, and control groups. Note. Improvement in upper and lower body strength reflects more pounds lifted; improvement in hip and shoulder flexibility reflects more degrees of range of motion; improvement in agility and balance and coordination reflects shorter time of exercise completion; improvement on diastolic and systolic blood pressure reflects lower blood pressure; and improvement in resting heart rate reflects fewer beats per minute. Values in negative show decline.

from 66 to 96 years, only 5 participants (3 in the walking group, none in the resistance-training group, and 2 in the control group) were less than 75 years of age. In addition, both exercise programs appeared to be feasible to sustain, at least for the 16-week duration of the study. Only 3 out of the 39 participants assigned to the two intervention groups did not complete the study (10% attrition). Both walking and resistance training led to substantial improvements in lower and upper body strength. In addition, we found improved hip and shoulder flexibility as well as agility and balance in both exercise groups, although these were not part of the intervention. Flexibility exercises were part of the warm-up routine administered before each exercise session. Cavani et al. (2002) found similar improvements in flexibility in a relatively younger cohort after 6 weeks of training with stretching and resistance-training exercises. Performing quick movements and changes in direction without losing balance becomes increasingly challenging with age (Bassey et al.,


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1992; Brown, Sinacore, & Host, 1995), potentially leading to higher incidence of falls (Buchner et al., 1997; Province et al., 1995). Therefore, the observed improvement in agility and balance may have important implications for functional ability. These findings support the notion that the benefits of exercise in this age group tend to be relatively universal, possibly because of relatively low levels of activity in advanced old age. In addition, it appears that walking, which requires no special equipment and may be more accessible to this age group than resistance training, may improve overall functional fitness in a similar way as resistance training. A paired-sample t test suggested a significant within-group reduction in systolic blood pressure in the resistance-training group (see Table 1). This finding, although only exploratory, may point to a potentially important health benefit given that systolic blood pressure is considered a good indicator of sclerotic arterial changes indicative of cardiovascular disease (e.g., Izzo, Levy, & Black, 2000). Several previous studies found improvement in cardiovascular health following aerobic exercise (Hagerman et al., 2000; Myers, 2003) or resistance training (Harris & Holly, 1987). Possibly, higher intensity or duration of training in our study may have led to cardiovascular benefits in the main analyses. The limitations of this study include the fact that test-retest results were not available. Additionally, a delayed follow-up would have been helpful in terms of the implications of our findings for long-term functional health and a larger sample would improve statistical power. Future research should examine the potential longer term benefits of exercise in this age group. Finally, the participants in this study resided in the same community. Although the participants were encouraged not to share information about intervention programs during the duration of the study, contamination across the control and intervention groups may have occurred. However, any contamination within the control group would mean that the results found in this study only underestimate the effect of intervention. In conclusion, the findings of this study indicate that previously sedentary adults in advanced old age can improve their functional fitness by engaging in a supervised exercise program. Both resistancetraining and walking programs yielded improvements on multiple measures of functional fitness, suggesting that benefits of exercise in

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advanced old age may be universal rather than specific to the type of exercise.

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