Previous investigation has noted that neither body build nor initial strength level appear to influence upper-body strength gains resulting from a short-term resistance training (RT) program in young men. Such information is lacking in young women. With increasing interest of women in RT, it would be beneficial to determine if the same outcome as noted in men is operating in women. PURPOSE: To determine the influence of body build on changes in upper-body strength resulting from different modes of RT in college women.
METHODS: College women (n = 708, age = 19.0 ± 0.9 yrs, Ht = 165.0 ± 6.0 cm, Wt = 62.6 ± 10.7 kg) self-selected to train with free weights or machine weights during 12 weeks of periodized RT 3 days/week. 1RM press was measured with free weights (FW, n = 170), supine vertical machine weight (SVP, n = 284), and seated horizontal machine weight (n = 232) before and after training. Fat mass (FM) and fat-free mass (FFM) were determined from a gender-specific skinfold %fat equation. Body build was determined by regressing FFM/Ht² on FM/Ht2. Body build was partitioned into thirds as slender (SL, n = 231), average (AV, n = 239), and solid (SO, n = 232) groups. RESULTS: The SVP group had a significantly greater initial 1RM (37.8 ± 8.5 kg) than the FW (35.6 ± 7.8 kg) and SHP (35.6 ± 7.8 kg) groups. SO body type (36.6 ± 8.3 kg) had a greater initial 1RM than SL (35.8 ± 8.0 kg) and AV (35.1 ± 8.4 kg) body types. Mode x body type ANOVA indicated that SVP (9.5 ± 6.2 kg) and SHP (8.8 ± 5.1 kg) made significantly greater 1RM gains than FW (4.9 ± 3.9 kg), while SO (9.3 ± 6.2 kg) and AV (8.8 ± 5.1 kg) body types made significantly greater gains than SL (6.9 ± 5.0 kg), with no significant interaction. Absolute strength gains had low correlations with initial strength in all modes (r = -0.08 to -0.26), accounting for no more than 7% of the common variance. Body type also had low correlations with absolute strength gains (r = 0.11 to 0.25). CONCLUSIONS: Young women appear to make slightly better initial strength gains using machine weights compared to FW. Body type does not appear to influence training potential to gain strength in women from RT using either mode. Thus, when beginning RT, young women of any body size or initial strength level can make significant gains using either free weights or machine weights.