Background: The lunge exercise is commonly adopted in public fitness programs. However, inadequate training experience and knowledge may result in improper actions, resulting in lowering training efficacy and possibly causing exercise-related diseases. Methods: Twenty-four male fitness trainees (12 novices and 12 experienced seniors) were recruited. Kinematics, kinetics, and muscle activation were measured during forward and backward lunges with different loading positions. Two-way repeated measures ANOVA and one-dimensional statistical parametric mapping (SPM1D) were employed to explore various between training experience across different loading positions and lunge directions. Results: Hip, knee, and ankle ROM and angle peaks were significantly greater in novices than in seniors (P < 0.001). During forward lunges, dumbbells reduced hip moments and stiffness in novices (P < 0.001), while barbells increased ankle moments in seniors (P = 0.022). In the backward lunges, novices showed increased negative power and significant joint instability with dumbbells. Conclusions: Training experience is the significant influence during male lunge exercises. Novices show more stability when using dumbbells instead of barbells for forward lunges. Novices are less stable during backward lunges than more experienced seniors. Overall, novices get a greater benefit of training with dumbbells, while seniors are less likely to hurt their knees and ankles when they use barbells.

This study aimed to examine the effects of wearable resistance (WR) training on change of direction ability (CODA), muscle activation patterns, and knee joint stress in athletes. Fifteen healthy male football players participated in a pre- and post-training intervention designed to target the quadriceps, hamstrings, and calf muscles to improve neuromuscular control and joint stability. Surface electromyography (EMG) was used to assess muscle activation, and finite element analysis (FEA) was applied to evaluate stress distribution in the knee joint. Following the WR training program, there was a significant reduction in knee abduction angle during the stance phase (p = 0.001), indicating enhanced joint stability. Strength in the calf muscles increased significantly, while muscle activation levels in the quadriceps (p < 0.001) and hamstrings (p = 0.007) were also elevated. Enhanced co-activation between quadriceps and hamstrings was observed, and FEA demonstrated a significant decrease in the maximal von Mises stress in the anterior cruciate ligament (ACL) and meniscus. These findings suggest that WR training improves CODA and lower limb muscle coordination while reducing internal knee joint stress, potentially lowering the risk of ACL injuries and enhancing athletic performance.