The Effect of the Experimental Training Program 'Grappler Quest' on the Motor Fitness of Brazilian Jiu-Jitsu Athletes

Background/Objectives: Despite the growing popularity of specialised training interventions aimed at developing motor abilities relevant to combat sports, scientific evidence regarding their effectiveness in Brazilian Jiu-Jitsu (BJJ) remains limited. This study aimed to estimate the effects of the experimental Grappler Quest (GQ) training program on the motor fitness profile of BJJ athletes and to explore whether training experience was associated with the magnitude of training-related changes. Methods: In this randomised trial, 44 competitive male BJJ athletes were allocated to an experimental group (EXP; n = 22) or a control group (CON; n = 22). Both groups followed an 8-week training protocol: the EXP group performed the structured GQ program, consisting of small circuit-based workouts, including resistance, plyometric, gymnastic, and BJJ-related exercises, whereas the CON group followed a standard BJJ training cycle. The motor profile was assessed before and after the intervention (pretest vs. posttest) using selected motor tests. The prespecified primary outcomes were strength-endurance performance in the bench press and squat performed with 50% body mass. Other motor-performance outcomes were treated as secondary or exploratory. Associations between training experience and intervention-related changes were analysed exploratorily. Results: ANCOVA of adjusted post-intervention means indicated between-group differences favouring the EXP group. Large effects were observed for the primary strength-endurance outcomes: bench press at 50% body mass (η² = 0.52) and squat at 50% body mass (η² = 0.40). Large effects were also observed for selected secondary outcomes, including pull-ups with a judogi (η² = 0.39), trunk flexibility (η² = 0.49), and maximal straddle sitting position (η² = 0.37) (all p < 0.001). After Benjamini-Hochberg false discovery rate adjustment, most between-group differences remained statistically significant, although secondary outcomes should be interpreted cautiously. In EXP, improvements were observed across multiple outcomes, including 1RM bench press (mean gain x~ = 5.23 kg), 1RM squat (x~ = 4.27 kg), pull-ups (x~ = 1.91 reps), judo-gi hangs (bent arms x~ = 3.91 s; straight arms x~ = 4.90 s), and flamingo balance (x~ = 4.59 s) (all p < 0.001). In the EXP group, exploratory correlations suggested that shorter training experience was generally associated with greater conditioning-related improvements, whereas flexibility and balance showed the opposite pattern. Conclusions: The GQ intervention package was associated with greater improvements in the motor fitness profile than standard BJJ training. The findings support the potential usefulness of structured circuit-based conditioning as an adjunct to standard BJJ practice, particularly for strength-endurance development. However, the study does not allow the isolated effect of the specific GQ exercise content to be separated from the effect of adding a structured conditioning block, and no direct conclusions can be drawn regarding injury prevention or return-to-play outcomes.