## 3 Results
### Single-Leg Vertical Hop Test  
Three months postoperatively, the jump height of the injured leg was only 59.6% that of the contralateral side (non-injured leg: 22.9 (6.2) cm vs. injured leg 13.5 (5.5) cm, \(p\) < 0.001; Figure 2, Table 2). At 6 months postoperatively, the jump height of the injured leg was significantly higher by 44.1% percent when compared to the 3-month value (13.5 (5.5) cm vs. 18.4 (6.9) cm, \(p\) < 0.001, Figure 1, Table 2). However, the LSI at 6 months postoperatively was still only about 79.6% (Table 2). The jump height of the non-injured leg did not change significantly from 3 months to 6 months postoperatively. There were no adverse events related to the SLVHT.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Characteristic** & **Study Population** \\ \hline Total [n] & 143 \\ \hline Gender (male/female [n (\%)]) & 94:49 (66\%:34\%) \\ \hline Age [years] & 26.6 (8.9) \\ \hline Height [cm] & 177.4 (8.3) \\ \hline Weight [kg] & 76.8 (13.7) \\ \hline BMI [kg/m\({}^{2}\)] & 24.3 (3.3) \\ \hline Injury due to the main sport practiced [n (\%)] & \\ Soccer & 66 (46\%) \\ Handball & 22 (15\%) \\ Other ball sports & 16 (11\%) \\ Tennis & 6 (4\%) \\ Winter sports & 8 (6\%) \\ Other sports & 5 (4\%) \\ No sports-related injury & 20 (14\%) \\ \hline Injured leg [n (\%)] & \\ Right & 65 (45\%) \\ Left & 78 (55\%) \\ \hline Diagnosis [n (\%)] & \\ ACL-R isolated & 59 (41\%) \\ ACL-R with meniscus involvement & 84 (59\%) \\ \hline \hline \end{tabular} Data are presented as the mean (standard deviation). Abbreviations: ACL-R, anterior cruciate ligament reconstruction; BMI, body mass index; n, number.  
\end{table}
Table 1: Demographic data of the study population.  
Figure 2: Jump height for the single-leg vertical hop test with the injured and non-injured leg at 3 and 6 months postoperatively in the total ACL-R population. Data are presented as the mean (standard deviation); n = 143; statistics: ***, \(p<0.001\).  
Differences in Jump Heights in the Single-Leg Vertical Hop According to Age, Gender and Injury Severity  
To examine whether age, gender and severity of injury had an effect on jump height, the jump height was comparatively analysed in the corresponding subgroups.  
Female patients had a lower jump height with the injured leg than did male patients at both 3 months and 6 months postoperatively (males vs. females: 3 months, 15.2 (5.4) cm vs. 10.2 (3.8) cm; 6 months, 21.1 (6.3) cm vs. 13.3 (4.9) cm; \(p<0.001\); Table 2). Even though the increase in jump height from 3 to 6 months was higher in males than females, the LSI did not differ significantly at both timepoints (LSI: 3 months, 59.6% (males) vs. 59.5% (females); LSI: 6 months, 80.6% (males) vs. 77.8% (females); \(p>0.5\)). An analysis of jump height in the SLVHT according to age indicated that the jump heights of the injured leg after 3 and 6 months of rehabilitation were higher in younger patients than in the older study group (age \(\leq\)30 years vs. \(>\)30 years: 3 months, 14.3 (5.5) cm vs. 11.4 (4.7) cm; 6 months, 19.5 (6.9) cm vs. 15.5 (6.0) cm; \(p<0.001\), Table 2). The LSI differed between both age groups at both timepoints postoperatively (age \(<\)30 years vs. \(>\)30 years: LSI: 3 months, 61.0% vs. 55.4% (\(p<0.05\)); LSI: 6 months, 81.0% vs. 75.6%). To our surprise, the jump height in the SLVHT with the injured leg did not differ between patients with isolated ACL-R and those with ACL-R with meniscal involvement, at both 3 and 6 months (Table 2).