Effects of Training Loads on Short-term Strength Adaptations in Older Adults

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: 51 untrained, healthy older adults (mean±SD age: 67.5±5.9; BMI: 29.4±6.6) 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. CONCLUSIONS: 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.