Effects of Training Loads on Short-term Strength Adaptations in Older Adults Sandor Dorgo, Ph.D., CSCS 1 , Rebecca J. Reed-Jones, Ph.D. 1 , Chantal A. Vella, Ph.D. 2 , Christina Samples, B.S. 1 , Chandrasekhar Bulusu, MHS(PT) 1 1 The University of Texas at El Paso, El Paso, TX; 2 University of Idaho, Moscow, ID ABSTRACT During the initial period of resistance training the rapid gains in muscular strength are mainly due to neuromuscular factors rather than morphological changes in the muscle tissue. It has been hypothesized that improvements in muscular strength may be elicited by simply practicing the resistance training movement and initial gains may be comparable to gains achieved through using an overload. PURPOSE: To compare changes in muscular strength in healthy older adults participating in a resistance training program using traditional resistance (TR) versus minimal resistance (MR). METHODS: 40 untrained, healthy older adults (mean±SD age: 67.7±6.5; BMI: 29.9±6.9) were recruited and randomly assigned to one of two groups: 1) TR group or 2) MR group. Training included five resistance training exercises (Bench Press, Lat Pulldown, Cable Upright Rows, Triceps Pressdown, and Leg Curl) for three sets of ten repetitions on two days per week for four weeks. Subjects in the TR group exercised using 75% of their predicted one repetition maximum (1RM). Subjects in the MR group used a 5 ft. PVC pipe for the bench press exercise, and the lowest weight on the selectorized weight training machines for the other exercises. Following the pre-testing six follow-up tests were conducted. All five resistance training movements were tested with a 4RM to 6RM testing procedure and 1RM strength were predicted using appropriate equations. Each testing session was followed by training. Data were analyzed using a general linear mixed model and alpha level was set at p<0.05. RESULTS: Both the TR and MR groups showed significant improvement (p<0.001) in strength for all five exercises from pre- to post-test. Strength improvements in the TR group ranged from 13.1% and 36.0%, while in the MR group from 11.1% to 27.4%. Group by time interactions were not significant for the Bench Press (p=0.97), Lat Pulldown (p=0.58), Cable Upright Row (p=0.94), Triceps Pressdown (p=0.31), and Leg Curl (p=0.29) exercises. CONCLUSION: Findings of this study indicate that initial improvements in muscular strength may be elicited by practicing proper exercise technique without using resistance overloads. This style of program design may provide a safe and effective method of introduction to resistance training in older adults. INTRODUCTION PURPOSE METHODS RESULTS CONCLUSION To compare the changes in muscular strength in healthy, previously untrained older adults participating in a resistance training program using traditional resistance (TR) versus minimal resistance (MR). • Mainly due to neuromuscular factors rapid strength gains may be observed during the initial period of training in untrained subjects. • Neuromuscular adaptations may be more pronounced in previously untrained older adults. • Muscular strength improvements may be elicited by simply practicing the resistance training movement with minimal resistance and initial gains may be comparable to gains achieved through using an overload. • Three sets of ten repetitions were performed for each exercise twice per week for 4 weeks. • Subjects in TR group used resistance of approximately 75% of 1RM. • Subjects in MR group used very low (i.e., < 10% 1RM) resistance. • Strength was measured pre- and post-intervention using 4RM to 6RM testing procedures . • 1 RM strength were predicted using appropriate equations. • Data were analyzed using a general linear mixed model. • Alpha level was set at p<0.05. • Significant strength improvements for all five exercises were observed in both the TR and MR groups from pre- to post- intervention (p<0.0001). • MR group showed similar strength improvements as the TR group from pre- to post-test. • Range of strength improvements was 13.1% to 36.0% in the TR group and 11.1% to 27.4% in the MR group. • Group by time interactions were not significant for the Bench Press (p=0.967), Lat Pulldown (p=0.583), Cable Upright Row(p=0.935), Triceps Pressdown (p=0.311), and Leg Curl (p=0.290) exercises. • Practice of proper exercise technique without using resistance overloads may promote initial strength gains similar to a traditional resistance training program in untrained older adults. • This style of program design can be a safe and effective method of introducing resistance training to older adults. ACKNOWLEDGEMENTS The project described was supported by Grant Number P20MD002287 from the National Institutes of Health (NIH), National Center on Minority Health and Health Disparities (NCMHD) through the Hispanic Health Disparities Research Center (HHDRC). The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH, NCMHD or HHDRC. Table 1. Descriptive characteristics of the subjects Participants: 14 Men and 26 Women (N=40) Group N Age (years)* Height (cm)* Weight (kg)* BMI(kg/m 2 )* TR 20 67.90 ± 6.85 162.45 ± 7.75 75.75 ± 23.44 28.48 ± 7.55 MR 20 67.49 ± 6.39 165.46 ± 7.51 85.15 ± 16.03 31.21± 6.16 Mean (± SD) pre-training subject descriptive characteristics. *p>0.14 between groups. Figure 1. Older adult subject demonstrates the bench press and the triceps pressdown exercises using minimal resistance RESULTS Table 2. Pre- and Post-test strength values and percent strength changes for the five experimental exercises in the TR and MR groups Exercise TR MR Group by Time p-value Pre-test (lb) Post-test (lb)** % Change Pre-test (lb) Post-test (lb)** % Change Bench Press 54.8±26.4 62.8±32.1 13.1±15.1 64.6±30.4 72.5±32.2 14.0±11.6 0.967 Lat Pulldown 93.8±27.6 110.3±33.7 17.9±12.9 110.8±28.1 122.7±31.7 11.1±9.8 0.583 Upright Rows 35.6±14.7 45.6±19.1 29.2±30.6 41.4±15.3 51.8±16.6 27.4±17.9 0.935 Triceps Pressdown* 35.7±12.4 43.4±15.6 22.0±24.1 46.0±13.8 54.2±14.65 19.8±11.4 0.311 Leg Curls 52.2±20.8 71.2±29.9 36.0±21.4 64.8±29.2 79.5±32.7 27.4±28.0 0.290 *Significant group effect for Triceps Pressdown exercises (p=0.026), no significant group effect for other exercises (p>0.11). **Significant time effect observed at post-test for all exercises (p<0.0001). METHODS • Longitudinal training intervention with pre- vs. post-test design. • Untrained older adults were randomly assigned to TR & MR groups. • Five exercises were performed to include: Bench Press, Lat Pulldown, Cable Upright Row, Triceps Pressdown, and Leg Curl.