The aim of this study was to investigate the whole-body biomechanical determinants of 180° change of direction (COD) performance. 61 male athletes (age: 20.7 ± 3.8 years, height: 1.77 ± 0.06 m, mass: 74.7 ± 10.0 kg) from multiple sports (soccer, rugby, and cricket) completed 6 trials of the modified and traditional 505 on their right leg, whereby 3D motion and ground reaction force data were collected during the COD. Pearson's and Spearman's correlations were used to explore the relationships between biomechanical variables and COD completion time. Independent T-tests and Hedges' g effect sizes were conducted between faster (top 20) and slower (bottom 20) performers to explore differences in biomechanical variables. Key kinetic and kinematic differences were demonstrated between faster and slower performers with statistically significant (p ≤ 0.05) and meaningful differences (g = 0.56-2.70) observed.Faster COD performers displayed greater peak and mean horizontal propulsive forces (PF) in shorter ground contact times, more horizontally orientated peak resultant braking and PFs, greater horizontal to vertical mean and peak braking and PF ratios, greater approach velocities, and displayed greater reductions in velocity over key instances of the COD. Additionally, faster performers displayed greater penultimate foot contact (PFC) hip, knee, and ankle dorsi-flexion angles, greater medial trunk lean, and greater internal pelvic and foot rotation. These aforementioned variables were also moderately to very largely (r or ρ = 0.317-0.795, p ≤ 0.013) associated with faster COD performance. Consequently, practitioners should focus not only on developing their athletes' ability to express force rapidly, but also develop their technical ability to apply force horizontally. Additionally, practitioners should consider coaching a 180° turning strategy which emphasizes high PFC triple flexion for center of mass lowering while P a g e | 2 also encouraging whole-body rotation to effectively align the body towards the exit for faster performance.

CUTTING ACTIONS ARE IMPORTANT MANEUVERS IN MULTIDIRECTIONAL SPORT AND ARE ALSO KEY ACTIONS ASSOCIATED WITH NONCONTACT ANTERIOR CRUCIATE LIGAMENT INJURY; HOWEVER, IT IS IMPORTANT TO NOTE THAT 3 PRIMARY CUTTING TECHNIQUES HAVE BEEN STUDIED WITHIN THE LITERATURE: THE SIDE-STEP, CROSSOVER CUT, AND SPLIT-STEP. THESE CUTTING TECHNIQUES DEMONSTRATE KINETIC AND KINEMATIC DIFFERENCES, WHICH HAVE DISTINCT IMPLICATIONS FOR BOTH PERFORMANCE AND POTENTIAL INJURY RISK. IN THIS REVIEW, WE DISCUSS THE ADVANTAGES AND DISADVANTAGES OF THE 3 CUTTING TECHNIQUES AND PROVIDE CUTTING TECHNICAL GUIDELINES, VERBAL COACHING CUES, AND CHANGE-OF-DIRECTION SPEED AND AGILITY PROGRAMMING RECOMMENDATIONS TO ENHANCE PERFORMANCE AND PROMOTE SAFER MECHANICS.

Objective: To assess the validity of the cutting movement assessment score (CMAS) to estimate the magnitude of peak knee abduction moments (KAM) against three-dimensional (3D) motion analysis, while comparing whole-body kinetics and kinematics between subjects of low (bottom 33%) and high CMASs (top 33%).

Cutting manoeuvres are important actions associated with soccer performance and a key action associated with non-contact anterior cruciate ligament injury; thus, training interventions that can improve cutting performance and movement quality are of great interest. The aim of this study, therefore, was to determine the effects of a six-week change of dire[ction (COD) speed and technique modification training intervention on cutting performance and movement quality in male youth soccer players (U17s, n = 8) in comparison to a control group (CG) (U18s, n = 11) who continued ‘normal’ training. Cutting performance was assessed based on completion time and COD deficit, and the field-based cutting movement assessment score (CMAS) qualitative screening tool was used to assess cutting movement quality. Significant main effects for time (pre-to-post changes) (p ≤ 0.041, η2 = 0.224–0.839) and significant interaction effects of time and group were observed for cutting completion times, COD deficits, and CMASs. Improvements in completion time (p < 0.001, g = 1.63–1.90, −9% to −11% vs. −5% to 6%) and COD deficit (p ≤ 0.012, g = −1.63 to −2.43, −40–52% vs. −22% to −28%) for the COD intervention group (IG) were approximately two-times greater than the CG. Furthermore, lower CMASs (i.e., improved cutting movement quality) were only observed in the IG (p ≤ 0.025, g = −0.85 to −1.46, −23% to −34% vs. 6–19%) compared to the CG. The positive changes in CMASs were attributed to improved cutting technique and reduced incidences of high-risk deficits such as lateral trunk flexion, extended knee postures, knee valgus, hip internal rotation, and improved braking strategies. The results of this study indicate that COD speed and technique modification training, in addition to normal skills and strength training, improves cutting performance and movement quality in male youth soccer players. Practitioners working with male youth soccer players should implement COD speed and technique modification training to improve cutting performance and movement quality, which may decrease potential injury-risk.