Force steadiness is quantified by evaluating the fluctuations in muscle force during constant-force contraction task. Aging is associated with a progressive impairment in force steadiness, indicating reduced sensorymotor function. Resistance and/or power training may improve force steadiness in aging individuals. However, the influence of resistance/power training on force steadiness in very old individuals (+80 yrs) remains unknown. PURPOSE: To examine the effect of resistance/power training on force steadiness in old (60 yrs) and very old (80 yrs) women. METHODS: Old (62.7 ± 2.2 yrs, n=20, TG60) and very old (81.8 ± 2.7, n=13, TG80) women performed 12 wks of heavy-resistance power training (HRPT) for the leg muscles (24 sessions) using training loads of 75-80% 1-RM. Two groups of non-training age-matched women served as controls (n=20, CG60; n=12, CG80). Force steadiness was evaluated during static unilateral leg extension at 20 and 60% MVC (30 and 20-s duration, respectively) using on-line visual display of the exerted force. RESULTS: Prior to training 80-yr women demonstrated impaired steadiness at 60% MVC reflected by elevated SD[force] and CV (SD[force]/force) and reduced accuracy (greater target force offset; TFO) compared to 60-yr women (p<0.05). No age deficits were observed at 20% MVC. Maximal static leg extensor strength (MVC) increased post training by 28.1 and 21.5% in TG80 and TG60, respectively (p<0.05). Post training SD, CV and TFO at 60% MVC decreased 30, 31 and 47% in TG60 (p<0.01) and 32, 36 and 39% in TG80 (p=0.01-0.06). No changes were observed in force steadiness at 20%. No changes were observed in the control groups. A 22% deficit in MVC between TG80 and CG60 was observed prior to training (p<0.05), which was removed after training (4.6%, n.s.). Likewise, pre training age deficits in SD, CV and TFO of 24, 8 and 35% all were reduced after training (-7,-14, 2%) (p<0.05). CONCLUSION: HRPT led to improved force steadiness at 60% MVC in old (60 yrs) and very old (80 yrs) women. Further, age related deficits in steadiness at 60% MVC disappeared after HRPT. No age deficits were observed at 20% MVC, where force steadiness remained unaffected by training. Resistance/power training appears to effectively enhance lower limb force steadiness control at moderate to high force levels in old and very old women (60-80 yrs).