abstract
-
Dynamic muscle strength (1 RM), symptom limited treadmill endurance, and bone mineral density and content, were compared among three groups (5 males and 5 females in each group) of elderly subjects (mean age of72.5 years) who had either continued to weight train twice per week for 5 years (TR), ceased to weight train after 2 years (DETR), or had acted as controls throughout (CON). The TR and DETR trained hard (progressing up to 3 sets at up to 80% of I RM) for 2 years; the TR continued training for an additional 3 years at a maintenance level (2-3 sets at 60-70% 1RM), whereas the DETR stopped training; the 10 CON subjects did not train for the duration of the study but took part in identical testing procedures. After two years of resistance training, dynamic strength in the TR and DETR groups increased significantly above the baseline and CON values for all exercises (p<0.0001). Following 3 years of maintenance level training, leg press, arm curl, and bench press 1 RM (sum of both limbs) in the TR remained 21.6kg (17%), 15.7kg (82%), and 8.3kg (34%) above baseline values respectively. The I RM in the DETR were 18.4kg (14%), 5.3kg (24%), and 1.4kg (9"10) above baseline for leg press, arm curl, and bench press after 5 years, whereas the CON declined over the 5 year period by 18.4kg (9.7%), 4.4kg (19"10), and 3.5kg (6%) respectively. There were non-significant improvements in treadmill performance in the TR and DETR and decline in the CON after 2 years of resistance training. Treadmill performance declined between years 2 and 5 in all groups. Bone mineral density and content were not different among the groups across all time points. We conclude that: 1) The strength gains from long-term resistance training in the elderly are not entirely lost even after 3 years of detraining, 2) The effects are specific to the exercises performed in the training program.