Cross-validity of one maximum repetition predictive equation for men with spinal cord injury

Objectives: The study aimed to test the cross-validation of a specific one maximum repetition (1RM) predictive equation based on the 4- to 12-maximum repetition test (4-12RM) for men with spinal cord injury (SCI). Study design: Cross-sectional study. Setting: Rehabilitation Hospital Network. Participants: Fifty-eight men aged 31.9 (20.0-38.0) years (median and quartile) with SCI were enrolled in the study. Interventions: None. Outcomes measures: Volunteers were tested in 1RM test or 4-12RM of the bench press exercise with 2-3 interval days in a random order. The intraclass correlation coefficient (ICC) with Bland Altman plot was used to compare a specific predictive equation (SPE) and six current predictive equations (CPE) based on the 4- to 12-maximum repetition with the 1RM test. Results: The SPE showed the highest intraclass correlation coefficient (ICC = 0.91; 95%CI 0.85-0.95), the smallest range of the interval around the differences (Δ = 36.6) and the second lowest mean difference between 1RM test and 1RM predictive equation (-2.4 kg). The CPE3 presented the lowest mean difference (-1.6 kg). All intraclass correlations' predictive equations were classified as excellent. Conclusion: The SPE presented a suitable and satisfactory validity to assess men with SCI at the bench press exercise. Thus, the equation is an accurate method to predict 1RM in SCI.