1. Effects of an In-Center Resistance Training Program on
Functional Measures, Strength, and Quality of Life in End Stage Renal Disease
M Bruneau Jr.1, J McKinnon1, M Germain2, T Matthews1, T Dodge1, P Dalton1, A LaCroix1, S Van Huysen1, and S Headley, FACSM1
Springfield College, Springfield, MA1, Renal & Transplant Associates of New England, Springfield, MA2
Table 2. Mean SPPB (±SD) changes across time by group.
Exercise
Control P
Baseline
4-wk
8-wk
Total Balance Score
2.3±1.4
2.6±0.9
3.1±1.0
3.3±1.2
3.4±1.1
3.1±1.5
.360
Total Gait Speed Score
1.3±0.5
1.2±0.4
1.0±0.0
1.1±0.4
1.4±0.5
.026**
Total Chair Stand Scores
1.0±1.2
1.5±1.4
1.9±1.7
1.8±1.3
2.3±1.6
2.4±1.7
.001*
Total SPPB Score
4.6±2.4
5.3±2.3
6.2±2.2
6.1±2.4
6.6±2.9
6.8±3.6
.008*
Abbreviations. C=control. E=exercise. SD=standard deviation. SPPB=Short Physical Performance Battery. wk=week. Note: * indicates a significant main effect. **indicates a significant interaction.
Table 1. Mean physical characteristics (±SD) of the study sample (N=20) by group.
Characteristic
Total (N=20)
Exercise (N=12)
Control (N=8)
Age (yr)
57.5±13.3
60.8±13.1
52.6±12.9
Height (in)
68.0±3.8
68.3±3.8
67.4±3.9
Weight (lbs)
213.2±52.1
213.6±50.8
212.6±57.6
BMI (kg⋅m-2)
32.7±8.4
32.5±8.5
33.0±9.2
Gender (%)
Male
55.0±0.5 (N=11)
58.3±0.5 (N=7)
50.0±0.5 (N=4)
Female
45.0±0.5 (N=9)
41.7±0.5 (N=5)
Ethnicity (%)
A. American
40.0±0.5 (N=8)
37.5±0.5 (N=3)
Caucasian
30.0±0.5 (N=6)
33.3±0.5 (N=4)
25.0±0.5 (N=2)
Hispanic
25.0±0.5 (N=3)
Abbreviations. A. American=American American. in= inches. kg⋅m-2=kilograms per meter squared. lbs=pounds. yr=year. %=percentage.
Background
Results
End stage renal disease (ESRD), defined as a glomerular filtration rate < 15 mL·min-1·1.73·m2-1 is a major public health issue in the United States (US).1-7 Over 571,000 Americans receive treatment for ESRD, most of whom are sedentary and frail.1-6 The prevalence of ESRD is higher among African, Hispanic, and Native Americans compared to non-Hispanic white Americans.1 Therefore, due its significant impact on US public health, the treatment of ESRD is a public health priority.
The treatment of ESRD involves the prescription of in-center hemodialysis, 3 days per week.1-6 Resistance exercise is also recommended by the American College of Sports Medicine (ACSM) to improve physical functioning among those living with ESRD.7 The ACSM’s current resistance exercise prescription for ESRD includes 8 to 10 exercises performed for 1 set at repetitions on non-dialysis days.7
Subject Characteristics: Subjects included non-Hispanic white, non-Hispanic black, and Hispanic men and women, who were middle-aged (57.5±13.3 yr) and obese (body mass index: 32.7±8.5 kg·m-2).
SF-36: For SF-36, physical composite scores were significantly higher in both groups across time (p=.023). No significant mean difference was found between groups (p>.05). For SF-36 mental composite scores, no significant mean differences were found between groups or across time (ps>.05).
SPPB: For SPPB, significant main effects for time were found for chair score (p=.001) and total SPPB score (p=.008). A significant interaction was also found for the 4-meter gait speed test (p=.026). Gait speed scores improved for C but not for E across time.
MMT: For MMT, significant group by time interactions were found for the following: right (p=.006) & left (p=.008) calf, right quadriceps (p=.003), right (p=.005) & left (p=.004) hamstrings, and right adductor (p=.020). MMT values increased for E but not C over time.
Purpose
To determine the effect of a supervised in-center resistance training program on functional measures, strength, and quality of life among a sample of patients living with ESRD.
Methods
Subjects: Twenty hemodialysis patients from Fresenius Medical Care Centers in Western Massachusetts were randomized to exercise (E, N=12) or control (C, N=8). Patients randomized to E received in‑center resistance exercise before and during treatment and included 8-10 exercise performed at moderate intensity (rating of perceived exertion [RPE] 3-5 on a 1-10 scale), for 1 set of repetitions, 3 days per week for 8 weeks. Patients randomized to C received usual care and no exercise. All patients were consented, oriented, and medically cleared prior to enrollment, and all testing procedures were approved by Springfield College’s Institutional Review Board and Fresenius Medical Care.
Functional Measures: Functional measures were assessed at baseline (BL), at 4-weeks (4-wk), and at 8-weeks (8-wk) with The Short Physical Performance Battery (SPPB). The SPPB assessment included a 3 or 4 meter gait speed test, a single and/or repeated chair stand test, and a feet together, semi-tandem, and/or tandem balance test. Each assessment was summed and scored on a 0-4 scale with higher scores indicating better functional outcomes. The total SBBP score was computed as the sum of the composite scores for each measure.
Strength Measures: Strength measures were assessed at BL, at 4-wk, and at 8-wk with the Layfayette Manual Muscle Testing (MMT) System. The muscles assessed included the right and left biceps brachii, deltoid, quadricep, hamstring, calf, abductor, and adductor. Strength was operationally defined as the peak force generated by the patient for each assessment and was measured in pounds (lbs).
Quality of Life: Quality of life measures were assessed at BL and at 8-wk with the Short Form (36) Health Survey (SF‑36). The survey uses an 8 scale profile to compute a weighted composite score for physical and mental health, respectively. The weighted composite is then transformed into a scale with higher scores indicating better physical or mental health perceptions.
Table 3. Mean MMT (±SD) changes across time by group.
Exercise
Control P
Baseline
4-wk
8-wk
Biceps R
29.0±19.4
34.9±15.8
37.4±16.5
26.6±13.3
33.2±17.7
28.1±22.1
.125 L
28.7±21.4
29.2±16.2
33.9±15.5
29.9±11.1
32.2±11.4
28.2±16.0
.865
Shoulder
29.7±16.5
30.9±15.5
32.5±13.2
29.8±16.7
29.5±13.2
27.1±14.2
.951
28.4±17.1
28.8±16.6
32.0±11.4
28.8±6
25.5±6.5
27.2±9.1
.455
Calf
23.4±11.3
31.7±14.8
32.6±9.8
40.6±18.9
32.3±13.4
38.4±12.7
.006**
22.4±11.7
29.4±11.1
36.0±12.8
34.8±19.9
29.3±11.8
31.7±9.5
.008*
Quadriceps
28.0±15.7
33.4±10.4
39.3±14.8
33.4±7.5
35.7±14.7
30.3±12.8
.003**
28.2±18.1
33.4±9.8
36.3±12.7
34.5±14.8
33.3±14.2
31.9±17.6
.589
Hamstrings
21.5±11.0
34.5±11.9
32.2±7.7
29.4±12.4
29.1±11.8
27.5±8.4
.005**
21.6±9.4
32.0±11.0
31.0±8.8
31.5±16.8
27.7±13.8
30.7±12.5
.004**
Adductors
21.7±9.9
25.0±8.3
27.2±8.3
28.5±13.3
24.1±10.8
24.4±6.6
.020**
22.9±10.9
23.2±8.0
27.0±7.0
24.8±17.3
21.9±10.0
21.1±7.7
.637
Abductors
28.7±14.0
34.9±16.2
35.5±17.6
32.4±16.4
32.6±17.5
33.1±10.6
.235
26.3±13.9
36.8±16.8
35.6±15.5
30.5±13.1
29.4±16.8
29.1±13.1
.193
Abbreviations. MMT=manual muscle testing. SD=standard deviation. wk=week. Note: *indicates a significant main effect. **indicates a significant interaction.
Conclusions
We examined the effect of a supervised in-center resistance training program on functional measures, strength, and quality of life among a sample of patients living with ESRD. We found the 8-wk resistance training program significantly improved lower body strength in E versus C, particularly for the right calf, the right quadriceps, and both the left and right hamstrings. We also found a significant interaction for the SPPB 4-m gait speed test and a significant main effect for the SPPB chair stand test. However, C was found to improve more than E. SF-36 physical composite scores improved similarly between groups across time.
Our findings indicate that implementation of a supervised 8-wk resistance exercise program may be efficacious for improving both functional and strength measures, and quality of life among those living with ESRD. Future research efforts should seek to replicate our findings in larger samples of men and women with ESRD and to elucidate the influence of in‑center resistance exercise on other biochemical variables that are associated with ESRD.
Statistical Analysis
SF-36: A 2 (group) X 2 (time) mixed factorial ANOVA with repeated measures was used to determine the effect of resistance exercise or control on quality of life. Post-hoc pairwise comparisons were performed for all significant main effects and interactions when appropriate. A Bonferroni correction factor was employed to adjust for multiple pairwise comparisons. Our predetermined alpha level was set at p<.05.
SPPB: A 2 (group) X 3 (time) mixed factorial ANOVA with repeated measures was used to determine the effect of resistance exercise or control on functional measures. Post-hoc pairwise comparisons were performed for all significant main effects and interactions when appropriate. A Bonferroni correction factor was employed to adjust for multiple pairwise comparisons. Our predetermined alpha level was set at p<.05.
MMT: A 2 (group) X 3 (time) mixed factorial ANOVA with repeated measures was used to determine the effect of resistance exercise versus control on strength measures. Post-hoc pairwise comparisons were performed for all significant main effects and interactions. A Bonferroni correction factor was employed to adjust for multiple pairwise comparisons when appropriate. Our predetermined alpha level was set at p<.05.
Acknowledgments
We thank Fresenius Medical Care for allowing us to access their patients treated at Western Massachusetts Kidney Center and Pioneer Valley Dialysis.