Influence of resistance exercise on lumbar strength in older, overweight adults.

OBJECTIVE: To measure lumbar extensor strength in overweight (OVW) and nonoverweight (NOVW) elderly adults before and after resistance exercise training (RX).
DESIGN: Descriptive, comparative study.
SETTING: University-based wellness center and research facility. PARTICIPANTS: Eighty-four adults (age range, 60-83 y) were placed into 1 of 2 groups based on body mass index (BMI): control (NOVW; mean BMI, 22.5 kg/m(2)) or OVW (mean BMI, 29.2 kg/m(2)). Subjects were then randomly assigned to either a resistance exercise (RX) or nonexercising group. INTERVENTION: Six months of total body RX and isolated lumbar extension exercise. MAIN OUTCOME MEASURES: Body composition, isometric lumbar extension strength, and 1-repetition maximum for each of the training exercises.
RESULTS: Upper-body strength increased by 18.3% and 17.2% for the NOVW-RX and OVW-RX groups, respectively. Lower-body strength increased by 12.7% and 19.5% for the NOVW-RX and OVW-RX groups, respectively. At baseline, the OVW participants had greater total lumbar extension strength (1067 Nm vs 714 Nm) compared with the NOVW participants (P<.05). When expressed per kilogram of fat-free mass, there were no differences in baseline total lumbar extension strength. After RX, lumbar extension strength increased by 58% and 34% for the NOVW-RX and OVW-RX groups, respectively (P<.05). No changes in lumbar extension, upper- or lower-body strength were noted for the nontraining groups.
CONCLUSIONS: OVW subjects were found to have greater absolute and similar relative, upper-body, lower-body, and lumbar extension strength at baseline when compared with their NOVW counterparts. Also, isolated lumbar extension exercise was effective in improving lumbar extensor strength in OVW and NOVW persons.

RCT Entities:   Population Interventions Outcomes