Koen Aldridge
Research Mentor: Lauren Opielinski Ortega
Mentor Department: , 0
Author(s): Koen M Aldridge, Lauren E Opielinski, Rachel N Logue Cook, Sandra K Hunter
Session: Session 7 (4:00 PM – 4:50 PM)
Presentation Type: Poster 118
Abstract
Introduction: Unilateral training, often used clinically when one limb cannot be loaded, is shown to increase strength on the untrained (contralateral) side of the body. In the literature, there is around a 7% increase on the contralateral side, however, it is not well known on how aging contributes to these differences (Munn et al 2005). Purpose: To investigate the contralateral effect of unilateral training in a case study of a healthy 78-year-old female. Methods: The participant (157cm, 52kg) completed a four-week (3 sessions / week) unilateral training protocol, consisting of structured exercise training sessions and experimental testing conducted pre- and post-training. During training sessions, the participant performed 20 minutes of unilateral high-intensity interval cycling on a specialized exercise bike, followed by four sets of eight unilateral leg extensions at 75% one repetition maximum (1RM) using the same limb. Measures for cardiorespiratory fitness (VO2peak via cycle ergometer), fatigue (the difference in power between the first five dynamic contractions and the last five during a set of 80 knee extensions at 20% MVC), and strength (maximal force and power of the knee extensors) were performed unilaterally in each individual lower limb to assess the changes due to training. Results: Following four weeks of training, the trained limb improved in VO2 peak by 15.6% (16.8 ml/kg/min vs 19.4ml/kg/min) with a 20% increase in peak workload achieved (50 W vs 60 W). Despite not training, the contralateral limb also improved in VO2 peak by 13.9% (17.2ml/kg/min vs. 19.6ml/kg/min), both pre and post achieved at a peak workload of 55W. Fatigability (relative reduction in power) decreased from pre- to post-training in the trained limb (41.7% vs. 28.4%) and did not change in the contralateral limb (39.9% vs. 38.6%). Unilateral 1RM of the knee extensors increased 25% (40lbs to 50lbs) on the trained limb, and 11.1% on the contralateral limb (45lbs to 50lbs). Conclusion: This case study represented a unique opportunity to train a 78 year old female and explore the impact of the contralateral training effect. These data suggest that unilateral training has a positive effect on the contralateral limb in older adults for fatigue, strength and cardiorespiratory fitness. As older adults acquire unilateral limitations, such as hip/knee surgery or strokes, training the stronger limb may help preserve strength in the weaker limb, all while increasing whole-body cardiovascular capabilities.
