# Knee Loading Asymmetries During Descent and Ascent Phases of Squatting After ACL Reconstruction
## 3 Results  
Forty participants were initially enrolled in the study. Five participants were lost to follow-up by 6 months after ACLR, resulting in thirty-five participants included in this analysis. Descriptive statistics for sex, age, race, weight, height and BMI of the included participants are presented in Table 1. More than half of the participants (54%) had a concomitant meniscal repair. Nearly two-thirds (63%) of participants had a patellar tendon autograft during ACLR. Overall limb loading (vGRFi) was more symmetric compared to knee-specific loading contributions (KFMi, HKRi) (Table 2, Figure 2). \begin{table}
\begin{tabular}{c c c} \hline \hline  & **Number of Participants** & **95\% Confidence** \\  & **(\%) or Mean (SD)** & **Interval** \\ \hline Sex (female) & 21 (60.0) & \\ \hline Age (years) & 19.7 (4.6) & 18.1–21.3 \\ \hline Race & & \\ Asian & 2 (5.7) & \\ Black or African American & 3 (8.6) & \\ Hispanic, Latino or Spanish & 3 (8.6) & \\ White & 25 (71.4) & \\ Other & 2 (5.7) & \\ \hline Weight (kg) & 74.2 (16.3) & 68.6–79.8 \\ \hline Height (m) & 1.7 (0.1) & 1.7–1.7 \\ Body mass index (BMI; kg/m\({}^{2}\)) & 25.9 (4.8) & 24.2–27.5 \\ Concomitant meniscus repair (Yes) & 19 (54.3) & \\ \hline Graft type & & \\ Hamstring tendon autograft & 4 (11.4) & \\ Patellar tendon autograft & 22 (62.9) & \\ Quadriceps tendon autograft & 8 (22.9) & \\ Allograft & 1 (2.9) & \\ \hline \hline \end{tabular} Abbreviations: %, percentage; SD, standard deviation; kg, kilograms; m, meters; BMI, body mass index.  
\end{table} 
Table 1: Participant and surgical characteristics. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**Descent (Mean \(\pm\) SD)**} & \multicolumn{3}{c}{**Ascent (Mean \(\pm\) SD)**} & \multirow{2}{*}{_p-Value_} \\ \hline  & **Injured** & **Uninjured** & **ILR** & **Injured** & **Uninjured** & **ILR** & _p-Value_ \\ \hline vGRFi (BW/kg\(\cdot\)m) & 0.48 \(\pm\) 0.12 & 0.52 \(\pm\) 0.13 & 0.93 \(\pm\) 0.12 & 0.45 \(\pm\) 0.10 & 0.51 \(\pm\) 0.10 & 0.90 \(\pm\) 0.14 & 0.045 * \\ \hline KFMi (N\(\cdot\)m\(\cdot\)s/kg\(\cdot\)m) & 0.22 \(\pm\) 0.10 & 0.35 \(\pm\) 0.15 & 0.70 \(\pm\) 0.39 & 0.18 \(\pm\) 0.09 & 0.32 \(\pm\) 0.11 & 0.64 \(\pm\) 0.39 & \textless{}0.001 * \\ \hline HKRi (N\(\cdot\)m\(\cdot\)s/kg\(\cdot\)m) & 1.74 \(\pm\) 0.71 & 1.12 \(\pm\) 0.53 & 1.84 \(\pm\) 0.93 & 2.04 \(\pm\) 0.84 & 1.17 \(\pm\) 0.53 & 2.06 \(\pm\) 1.12 & 0.006 \\ \hline Time (s) & \multicolumn{3}{c}{1.00 \(\pm\) 0.25} & \multicolumn{3}{c}{0.96 \(\pm\) 019} & 0.036 * \\ \hline \hline \end{tabular}  
* \(p\)-value of \(<\)0.05. Abbreviations: SD, standard deviation; ILR, interlimb ratio; vGRFi, vertical ground reaction force impulse; BW, bodyweight; s, seconds; kg, kilograms; m, meters; KFMi, external knee flexion moment impulse; N, neutrons; HKRi, ratio of external hip flexion to knee flexion moment impulse.  
\end{table} 
Table 2: Results of interlimb ratios for vertical ground reaction force impulse, external knee flexion moment impulse and ratio of external hip flexion to knee flexion moment impulse, as well as time during the different phases of squats. There was a significant difference in loading asymmetry between the descent and ascent phases of bilateral squats for all biomechanical variables (Table 3). Participants demonstrated more asymmetry during the ascent phase for vGRFi ILR (\(p\) = 0.045; Descent (D): 0.93 \(\pm\) 0.12, Ascent (A): 0.90 \(\pm\) 0.14), KFM i ILR (\(p\) < 0.005; D: 0.70 \(\pm\) 0.39, A: 0.64 \(\pm\) 0.39) and HKRi ILR (\(p\) = 0.006; D: 1.84 \(\pm\) 0.93, A: 2.06 \(\pm\) 1.12) (Figure 1). There was a significant difference in time with the ascent phase being faster than the descent phase (\(p\) = 0.036; D:1.00 \(\pm\) 0.25 s, A:0.96 \(\pm\) 0.19 s) (Figure 2).