## 2 Materials and Methods
### Protocol  
Seven highly trained recreational male cyclists and triathletes voluntarily participated in the study. Cyclists verbally confirmed that they cycle on average 15,000 km per year. The subjects' mean age was 31.4 \(\pm\) 3.7 years, body height 178.1 \(\pm\) 1.1 cm, and body mass 73.5 \(\pm\) 4.5 kg. They used their own bike, so no bike setup was needed. The bike was mounted on a direct drive ergo-trainer (Elite Drivo, Treviso, Italy) which allowed it to set up a constant workload, and which has been proven reliable [17]. The subjects used a clipless shoe-pedal system, while the pedal float (only left-right) was not defined as it did not affect the calculations.  
The right leg was analyzed. The kinematics data were collected using a 3D high-speed motion-capturing system with active LED markers (NDI Certus, Waterloo, ON, Canada). The system was calibrated at the start of the experiment, while the digitizing probe was calibrated for each subject separately. Forces and torques were collected with a six-component force-torque pedal system (Forped, Cycling Science, d.o.o., Ljubljana, Slovenia), and a customized software (ARS Free Measurement, S2P, d.o.o., Ljubljana, Slovenia) was used. Pedal dynamometer offset was corrected prior to each trial. All data were further processed with a bespoke script written in MATLAB (MathWorks R2018a, Inc., Natick, MA, USA, 2018).  
First, the marker setup was established and markers were digitized. After the warm-up, static calibration was performed. The subjects sat still on the bicycle for ten seconds with the right leg clipped to the pedal semi-extended in a way that the pedal was in the lowest position. The fourth to sixth seconds of the raw data from the static calibration were averaged to minimize the error. Following the static calibration, subjects rode for five  
Figure 3: Joint coordinate system with forces and torques orientation in each segment’s local coordinate system.  
minutes at a workload of 75% of their maximal power with a cadence of 85 rpm, while the gear ratio was not defined. Data from the first and the last minute were analyzed and compared. Data were presented as an ensemble average of the whole minute recorded, from which the joint/pedal forces and torques were calculated. The sampling rate of kinematics data was 128 Hz, while kinetics data had a sampling rate of 1000 Hz and were down-sampled in the post-analysis. A +3 V trigger was used to synchronize kinematics and kinetics data. The kinematics and kinetics data were smoothed with a fourth-order, zero phase shift low-pass Butterworth filter with a cut-off frequency of 12 and 8 Hz, respectively.  
The minimum (min) and maximum (max) joint force and torque were calculated from the average values of one crank cycle (which is specified by z-coordination of the pedal marker 360\({}^{\circ}\) degree clockwise from top dead center) using mean top decile as shown in Equations (13a) and (13b):  
\[\text{max} = (max-min)*0.9+min \tag{13a}\]  
\[\text{min} = (min-max)*0.9+max \tag{13b}\]  
The intra-class coefficients of the correlation (ICC), Cronbach's alpha, and \(t\)-test without a statistically significant difference were used to assess the intra-session reliability between two trials of the measured parameters. Statistical analyses were performed using SPSS V.24 for Windows (IBM Corporation, Somers, NY, USA, 2018) with levels of significance set to \(p<0.050\).