# Stride Length Impacts on Sagittal Knee Biomechanics in Flat Ground Baseball Pitching
## 4 Discussion  
The baseball pitch is one of the most dynamic of athletic skills. However, the complex interaction between stride length modification as a compensatory biomechanical response to central and peripheral fatigue on pitching mechanics may amplify shoulder and elbow joint torques and exacerbate throwing arm injuries. Over the course of a game, adjusting the pitching mechanics may be a reactive response to a cumulative workload (number of pitches and aggregate innings), as evidenced by altering the stride length that elicits compensatory lower extremity mechanics followed by the trunk and throwing arm in succession. Biomechanical changes to maintain or increase fastball velocities can affect forward propulsive and braking ground reaction force parameters, which may be a better indicator of exertion that can be monitored [19]. Given the paucity of research examining coordinated drive and stride leg intersegmental knee joint dynamics (kinematic and kinetic parameters) in baseball pitching, our retrospective analysis of the existing data from an original single cohort during simulated flat ground baseball game pitching confirmed our \begin{table}
\begin{tabular}{c c c c c c c c c} \hline  & & **Peak Knee Height** & **Generation Phase** & **Stride Foot Contact** & **Brace- Transfer** & **Maximal Rotation** & **Acceleration Phase** & **Ball Release** \\ \hline \multirow{3}{*}{Joint Angle (\({}^{\circ}\))} & OVER-STRIDE & \(-34.3\) & \(-50.8\)*\({}^{\times 3}\) & \(-42.8\) & \(-30.4\)***\({}^{\times 3}\) & \(-27.3\) & \(-30.7\) & \(-32.6\) \\  & (13.3) & (6.28) & (13.3) & (5.57) & (13.6) & (15.9) & (17.4) \\  & UNDER-STRIDE & \(-31.3\) & \(-42.8\) & \(-45.7\) & \(-37.7\) & \(-25.8\) & \(-29.3\) & \(-32.8\) \\  & (14.5) & (5.89) & (13.8) & (7.57) & (14.0) & (2.63) & (17.0) \\ \hline \multirow{3}{*}{\begin{tabular}{c} Angular \\ Velocity (\({}^{\circ}\)/s) \\ \end{tabular} } & OVER-STRIDE & \(-49.6\) & \(-4.99\)*\({}^{\times 3}\) & \(112.7\)* & \(76.8\) & \(-133.6\) & \(-139.9\)*\({}^{\times 3}\) & \(-128.2\) \\  & (51.6) & (63.8) & (142.8) & (118.4) & (169.0) & (6.43) & (169.4) \\  & UNDER-STRIDE & \(-34.6\) & \(-21.9\) & \(14.0\) & \(101.0\) & \(-109.5\) & \(-198.3\) & \(-222.1\) \\  & (42.8) & (28.7) & (97.5) & (74.4) & (184.7) & (40.9) & (164.3) \\ \hline \multirow{3}{*}{\begin{tabular}{c} Joint \\ Moments \\ (\%BW *H) \\ \end{tabular} } & OVER-STRIDE & \(25.3\) & \(32.8\) & \(17.8\) & \(18.9\)*\({}^{\times 3}\) & \(11.7\)*\({}^{\times 3}\) & \(1.16\) & \(-16.4\) \\  & (23.4) & (14.5) & (33.3) & (3.76) & (17.0) & (12.0) & (45.5) \\  & UNDER-STRIDE & \(22.7\) & \(29.2\) & \(6.68\) & \(7.57\) & \(-6.18\) & \(-7.48\) & \(-9.62\) \\  & (16.9) & (9.33) & (34.7) & (4.23) & (14.9) & (1.43) & (16.4) \\ \hline \multirow{3}{*}{\
\begin{tabular}{c} Joint Power \\ (W/BW *H) \\ \end{tabular} } & OVER-STRIDE & \(-13.2\) & \(-2.68\) & \(37.3\) & \(31.7\) & \(-10.9\) & \(-1.50\)*\({}^{\times 3}\) & \(12.3\) \\  & (14.8) & (18.9) & (56.7) & (26.2) & (44.1) & (10.0) & (24.6) \\ \cline{1-1}  & UNDER-STRIDE & \(-9.08\) & \(-5.86\) & \(10.8\) & \(33.4\) & \(8.07\) & \(21.4\) & \(27.5\) \\ \hline \multirow{3}{*}{
\begin{tabular}{c} Joint \\ Moments \\ (\%BW *H) \\ \end{tabular} } & Mean (SD) for drive knee flexion (\(-\)) and extension (\(+\)), angular displacements (degrees), angular velocities (degrees/second), normalized moments (\% body weight \(\times\) height), and joint powers (watts/body weight \(\times\) height), generation (\(+\)) and absorption (\(-\)). Significant differences indicated (\(p\leq 0.001\)) ** and (\(p\leq 0.05\)) *. Effect size: trivial (\(<\)0.2) no symbol; small (0.2–0.49) \({}^{\dagger}\); large (\(\geq\)0.8) \({}^{\times}\). \\ \hline \end{tabular}
\end{table} 
Table 1: Drive knee flexion/extension dynamics.