## 3 Results
### Detailed Analysis of the Cycle of a Repetition for a 5 kg Machine Load  
In Section 3.2 the procedure from Section 3.1 and the execution mode of the reference set was repeated, with a machine load of 5 kg. As seen in Figure 7, the medium duration of a typical repetition was 1.53 s, according to MNR = 40, and the total duration of a set was 61.49 s. Comparing to the duration of a typical cycle of repetitions of 2.26 s, in this case, the duration was reduced by 32%. The frequency of the repetitions was increased, which highlights that, due to the aim of obtaining as high an MNR value as possible, there was a tendency to increase the speed of execution. This translated into higher accelerations and values of the maximum force, which exceeded 0.105 kN, more than twice the load of the Scott machine. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **M** & **N** & **SD** \\ \hline R24\_Fmax & 0.138 & 30 & 0.006 & \\ R2\_Fmax & 0.127 & 30 & 0.004 & \\ \hline  & **M** & **SD** & \(t\) & **df** & \(p\) \\ \hline Pair R24\_Fmax–R2\_Fmax & 0.011 & 0.007 & 8.14 & 29 & \(\leq\)0.001 \\ \hline \hline \end{tabular}  
* M—mean; N—number of subjects; SD—standard deviation; \(t\)—\(t\)—value; df—degrees of freedom; \(p\)—level of significance; R24—final repetition; R2—initial repetition.  
\end{table} 
Table 3: Paired-samples test: pair R24_Fmax–R2_Fmax. Hence, the first important conclusion for this loading case was the tendency of subjects to increase the execution speed; this allowed an increase in the acceleration, transposed in the maximum double force compared to the loading of the machine, compared to an increase of only 35% in the case of loading in Section 3.1. This observation also takes into account the 8.4% longer duration of the set, so a higher time-under-tension of the bicep muscle (i.e., 61.49 s vs. 56.64 s). Although the load of the machine was reduced by half, the maximum force during the set was reduced by 22.2% (i.e., 0.105 kN vs. 0.142 kN), and the duration of the set, and therefore, the time under tension, increased by only 8.4%. The intensity of %IRM was, in this case, 39%, which, for a number of 40 repetitions seems a high value. The explanations for the higher load are, thus, reconfirmed, with a special role of compensatory acceleration in the case of bicep curls, through which the subjects tried to pass quickly over the critical points in the concentric phase. Table 4 presents the maximum values of the force for the execution cycle. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Repetition** & **Fmax (kN)** & **t (s)** & **Repetition** & **Fmax (kN)** & **t (s)** \\ \hline R1 & 0.077 & 2.25 & R21 & 0.105 & 27.78 \\ R2 & 0.094 & 3.88 & R22 & 0.092 & 29.00 \\ R3 & 0.096 & 5.16 & R23 & 0.092 & 30.30 \\ R4 & 0.1 & 6.32 & R24 & 0.097 & 31.68 \\ R5 & 0.095 & 7.5 & R25 & 0.091 & 32.96 \\ R6 & 0.097 & 8.7 & R26 & 0.102 & 34.35 \\ R7 & 0.089 & 9.86 & R27 & 0.092 & 35.71 \\ R8 & 0.1 & 11.17 & R28 & 0.093 & 37.11 \\ R9 & 0.098 & 12.44 & R29 & 0.094 & 38.53 \\ R10 & 0.091 & 13.76 & R30 & 0.098 & 39.89 \\ R11 & 0.093 & 15.07 & R31 & 0.091 & 41.37 \\ R12 & 0.1 & 16.31 & R32 & 0.092 & 42.88 \\ R13 & 0.096 & 17.57 & R33 & 0.089 & 44.56 \\ R14 & 0.104 & 18.89 & R34 & 0.091 & 46.48 \\ R15 & 0.103 & 20.13 & R35 & 0.093 & 48.24 \\ R16 & 0.1 & 21.44 & R36 & 0.094 & 50.18 \\ R17 & 0.1 & 22.72 & R37 & 0.092 & 52.22 \\ R18 & 0.1 & 23.96 & R38 & 0.091 & 54.36 \\ R19 & 0.096 & 25 & R39 & 0.095 & 57.04 \\ R20 & 0.101 & 26.504 & R40 & 0.091 & 60.35 \\ Fmax (kN) & & & 0.095 & & \\
1 RM (kN) & & & 0.242 & & \\ \%IRM & & & 39\% & & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Maximum forces per repetition—5 kg machine load. Figure 7: Evolution of forces versus time for execution to the point of refusal—5 kg load. The evolution of the maximum forces for the entire cycle is presented in Figure 8a. The dynamics of the maximum forces per cycle demonstrate much better regularity than in the case of the higher loading of the Scott machine, suggesting better execution accuracy.