de Camargo, Júlio Benvenutti Bueno; Braz, Tiago Volpi; Batista, Danilo Rodrigues; Germano, Moisés Diego; Brigatto, Felipe Alves; Lopes, Charles Ricardo

Journal of Strength and Conditioning Research: August 2022 - Volume 36 - Issue 8 - p 2089-2093, doi: 10.1519/JSC.0000000000003811

PURPOSE:

To compare the time course of indirect markers of muscle damage after multi-joint and single-joint exercises.

PROCEDURES:

10 resistance-trained men:

Age: 26.9 years.

Body wt. = /83.2 kg.

Height: /176 cm.

Training experience = 5.5 years.

Pre-tests: back squat (BS) 1-RM and 8-RM and leg extension (LE) 8-RM.

The subjects completed 5 sets with an 8-RM for a maximum number of reps in either the BS or LE exercises in each of the 9 scheduled training sessions.

Measurements of the rectus femoris muscle thickness (RFMT), leg circumference (LC), and muscle soreness (MS) were recorded at pre-training, immediate post-training, then at 12, 24, and 36 hours post-training.

CONCLUSIONS:

There were significant increases in dependent variables at every time point after both the multi-joint and single-joint exercise sessions. However, RFMT and LC were greater at immediate post-training and 36 hours, and MS was greater at 24 and 36 hours after BS when compared with LE.

IN PLAIN ENGLISH:

Performing the multi-joint back squat for 5 sets of 8 reps to muscle fatigue resulted in higher levels of indirect markers of muscle damage as compared to performing the single joint leg extension. The greater the amount of muscle structures activated in an exercise, the greater the stress placed on the body.