A Minimal Training Protocol Improves Strength And Aerobic Fitness In Trained And Untrained Populations

PURPOSE: This NASA funded study examined the effects of a minimal dose exercise strategy on body composition, strength, and aerobic fitness. METHODS: Participants, (6 M/3F, (mean ± SD), 31 ± 6y, 174 ± 12 cm, 82 ± 25 kg, 31.8 ± 10.7 ml⋅kg⋅min-1) Trained (VO2max > 35 ml⋅kg⋅min-1, 41.2 ± 8.2 ml⋅kg⋅min-1, 3 M/1F, 29 ± 5y, 173 ± 7 cm, 68 ± 6 kg), and untrained, (24.2 ± 3.8 ml⋅kg⋅min-1, 3 M/2F, 32 ± 7y, 175 ± 15 cm, 94 ± 28 kg) completed the 12-week intervention with testing at baseline (PRE), 6 weeks (MID), and 12 weeks (POST). Testing included one repetition maximum (RM) and 10RM of resistance exercises (overhead press, (OHP) lat pulldown, leg press, seated row, bench press, and deadlift). We assessed VO2max, VO2peak, running economy, vertical jump, and body composition. Participants exercised weekly at one-hour sessions, including interval (5x1min bouts at 105 ± 17% of maximum wattage (Wmax) with 1.5 min rest), resistance (one set of 25-30 repetitions to failure at 64 ± 16%1RM), and functional plyometric training (10 min of repeating exercises). RESULTS: Maximal (1RM) and submaximal (10RM) strength increased (vs. PRE, p < 0.05), ≥17.8% and ≥ 25.7% respectively, at POST for all exercises (Figure 1a). Both trained and untrained increased 1RM and 10RM at POST (vs. PRE, p < 0.05), except for trained OHP 1RM, bench press 10RM, and untrained seated row 1RM (Figure 1b). VO2max increased (vs. PRE, p < 0.05) at MID and POST. Untrained VO2max increased 12% (vs. PRE, p < 0.05). Trained VO2max increased non-significantly (14%, p = 0.2, Cohen's d = 0.79) with a significant increase in Wmax 9% (vs. PRE, p < 0.05). Participants maintained body composition, running economy, VO2peak, and vertical jump (vs. PRE, p > 0.05). Notably, untrained VO2peak increased 13%, a substantial effect (vs. PRE, p = 0.055, Cohen’s d = 1.37). CONCLUSION: This minimal dose intervention, one-tenth of current recommendations, improves strength and cardiovascular performance while preserving power, body composition, and running economyNASA CTSGC (P-1708) under PTE Federal Award No: 80NSSC20M0129.