## 3 Results  
Table 1 shows the 1 RM strength test results for the traditional SLP and BIOFIT-LP machines. Table 2 and Figure 4 show the mean and standard deviation of the root mean square recorded in each of the muscles analyzed during the use of the SLP at 60 and 75% of 1 RM, the BIOFIT-LP at 60 and 75% of 1 RM, and the OFE-SLP with self-weight as intensity of the exercise. In all cases, it was found that the vastus lateralis was the muscle group that attained the greatest activation, followed by the recuts femoris, and thirdly by the tibialis anterior. After these, in the case of SLP and BIOFIT-LP, the next muscle groups with the highest activation were the biceps femoris and gastrocnemius, in that order; while with the OFE-SLP machine, the order of the latter was reversed. \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **1 RM** & **60\% 1 RM** & **75\% 1 RM** \\ \hline SLP (kg) & 201.51 \(\pm\) 35.35 & 120.91 \(\pm\) 21.21 & 151.14 \(\pm\) 26.51 \\ BIOFIT-LP (kg) & 56.31 \(\pm\) 13.72 & 31.85 \(\pm\) 11.27 & 39.82 \(\pm\) 14.09 \\ \hline \hline \end{tabular} iRM = one-repetition maximum; BIOFIT-LP = BIOFIT leg press; SLP = traditional seated leg press.  
\end{table} 
Table 1: Results of the 1 RM strength test. Figure 4: Root mean square (\(\mu\)V) representation of the electromyographic signal in the different machines with different 1 RM intensities. \begin{table}
\begin{tabular}{c c c c c c} \hline  & **VL (M \(\pm\) SD)** & **RF (M \(\pm\) SD)** & **BF (M \(\pm\) SD)** & **TA (M \(\pm\) SD)** & **GN (M \(\pm\) SD)** \\ \hline Complete & & & & & \\ \hline SLP 60\% & 199.17 \(\pm\) 61.46 & 134.96 \(\pm\) 50.57 & 64.77 \(\pm\) 38.23 & 68.29 \(\pm\) 37.92 & 61.43 \(\pm\) 32.66 \\ SLP 75\% & 241.01 \(\pm\) 70.83 & 176.98 \(\pm\) 72.18 & 82.17 \(\pm\) 39.51 & 88.08 \(\pm\) 37.27 & 77.65 \(\pm\) 37.31 \\ BIOFIT-LP 60\% & 219.09 \(\pm\) 69.23 & 149.25 \(\pm\) 64.14 & 57.51 \(\pm\) 33.48 & 133.69 \(\pm\) 63.86 & 39.48 \(\pm\) 20.78 \\ BIOFIT-LP 75\% & 235.99 \(\pm\) 75.52 & 162.60 \(\pm\) 67.85 & 67.91 \(\pm\) 36.25 & 140.83 \(\pm\) 80.50 & 43.11 \(\pm\) 19.41 \\ OFE-SLP & 66.89 \(\pm\) 26.28 & 30.00 \(\pm\) 17.76 & 21.22 \(\pm\) 10.04 & 58.18 \(\pm\) 55.18 & 40.18 \(\pm\) 26.93 \\ \hline \multicolumn{5}{c}{Concentric} \\ \hline SLP 60\% & 224.98 \(\pm\) 66.44 & 149.84 \(\pm\) 60.63 & 77.11 \(\pm\) 38.01 & 81.63 \(\pm\) 46.72 & 75.83 \(\pm\) 41.86 \\ SLP 75\% & 274.71 \(\pm\) 80.92 & 206.55 \(\pm\) 88.28 & 95.83 \(\pm\) 43.83 & 100.44 \(\pm\) 49.77 & 90.85 \(\pm\) 40.21 \\ BIOFIT-LP 60\% & 251.12 \(\pm\) 80.71 & 157.21 \(\pm\) 74.59 & 69.14 \(\pm\) 30.52 & 104.11 \(\pm\) 51.47 & 48.86 \(\pm\) 26.96 \\ BIOFIT-LP 75\% & 271.15 \(\pm\) 91.27 & 175.80 \(\pm\) 74.10 & 82.08 \(\pm\) 38.36 & 120.86 \(\pm\) 67.79 & 50.45 \(\pm\) 22.55 \\ OFE-SLP & 75.26 \(\pm\) 32.99 & 28.09 \(\pm\) 13.92 & 25.92 \(\pm\) 12.39 & 38.52 \(\pm\) 31.77 & 49.11 \(\pm\) 32.26 \\ \hline \multicolumn{5}{c}{Eccentric} \\ \hline SLP 60\% & 168.86 \(\pm\) 66.04 & 114.56 \(\pm\) 56.17 & 39.28 \(\pm\) 26.53 & 49.32 \(\pm\) 31.60 & 41.51 \(\pm\) 23.71 \\ SLP 75\% & 196.34 \(\pm\) 70.17 & 138.85 \(\pm\) 60.05 & 50.26 \(\pm\) 27.46 & 68.47 \(\pm\) 30.36 & 53.89 \(\pm\) 27.49 \\ BIOFIT-LP 60\% & 179.06 \(\pm\) 59.44 & 138.64 \(\pm\) 63.56 & 26.94 \(\pm\) 11.79 & 151.36 \(\pm\) 89.07 & 24.41 \(\pm\) 13.89 \\ BIOFIT-LP 75\% & 187.59 \(\pm\) 60.51 & 146.03 \(\pm\) 68.19 & 32.87 \(\pm\) 15.79 & 153.58 \(\pm\) 104.76 & 30.84 \(\pm\) 18.44 \\ OFE-SLP & 57.08 \(\pm\) 27.61 & 28.70 \(\pm\) 19.35 & 16.00 \(\pm\) 9.36 & 64.52 \(\pm\) 70.84 & 30.65 \(\pm\) 23.68 \\ \hline \end{tabular}
\begin{tabular}{c c c c c} \hline  & **BF =** biceps** & BIOFIT-LP = BIOFIT leg & **GN =** gastrocnemius** & **OFE-SLP =** \\ \multicolumn{5}{c}{femoris} \\ \multicolumn{5}{c}{femoris} \\ \multicolumn{5}{c}{femoris} \\ \multicolumn{5}{c}{SF =** traditional** seated leg** & **was** & **t** \\ \hline \end{tabular}
\end{table} 
Table 2: Root mean square (\(\mu\)V) recording of the electromyographic signal in the different machines with different 1 RM intensities.