Effect of training on the relationship between maximal and submaximal strength

Area of Science:

• Sports Science
• Exercise Physiology
• Strength and Conditioning

Background:

• Accurate assessment of maximal strength is crucial for training prescription and performance monitoring.
• The one-repetition maximum (1-RM) test is a gold standard but can be time-consuming and potentially risky.
• Dynamic submaximal tests, like the 7-10 RM test, offer a potentially safer and more practical alternative.

Purpose of the Study:

• To determine the validity of a dynamic 7-10 repetition maximum (RM) test for estimating maximal knee extension strength (1-RM).
• To assess the accuracy of the 7-10 RM test in both untrained and resistance-trained individuals.
• To evaluate how training affects the relationship between 7-10 RM and 1-RM strength.

Main Methods:

• Fifty-eight participants (33 men, 25 women) were assigned to a training (N=47) or control (N=11) group.
• The training group underwent 18 weeks of knee extension training (2-3 sessions/week).
• One-repetition maximum (1-RM) and 7-10 RM tests were administered before (T1) and after (T2) the training period.

Main Results:

• The training group significantly improved both 1-RM (31.7%) and 7-10 RM strength (51.4%) (P < 0.01).
• The relative strength assessed by the 7-10 RM test increased from 68.4% of 1-RM at T1 to 79.1% of 1-RM at T2 (P < 0.01).
• A linear equation (1-RM = 1.554*(7-10 RM weight) - 5.181) accurately predicted 1-RM at T1 (R2=0.89).
• This equation systematically overpredicted 1-RM by 21.2 kg in trained subjects at T2 (P < 0.01).

Conclusions:

• The dynamic 7-10 RM test is a valid method for estimating 1-RM in untrained individuals.
• Resistance training alters the relationship between 7-10 RM and 1-RM strength.
• The established prediction equation for 1-RM is not accurate for trained individuals post-training, necessitating adjustments for this population.