## 4 Discussion
Ankle sagittal plane differences occurred during 14% of the cycle, and ankle frontal and transverse plane differences were observed during 4% and 3% of the cycles, respectively. Moreover, the continuous analysis using POR, further reduced these differences by decreasing the magnitude of statistical significance at the sagittal plane motion and eliminating differences between HFgait and cycling in the transverse plane. These findings suggest that differences in ankle motion between HFgait and cycling are minimal and might not represent impactful differences for exercise prescription. Additionally, this further highlights the importance of continuous analysis (SPM) and POR when comparing kinematic patterns from different activities. In this study, this type of analysis provided a more accurate and meaningful interpretation of the potential differences in ankle joint motion between HFgait and cycling. Restricted join ROM appears to be an important risk factor for the occurrence of locomotor disability in patients with osteoarthritis. Manual therapy and therapeutic exercises are recommended for the treatment of lower limb impairments that involve limited range of motion. Both approaches use specific exercises that target specific limitations in functional range of motion of the knee or hip because such maximum or minimum joint angles might be difficult to achieve during daily life activities and commonly used exercise modalities. HFgait might be a valid option to maximize hip and knee range of motion while receiving cardiovascular benefits from aerobic exercise. Hip and knee sagittal plane range of motion during HFgait involves approximately 78% and 80% of the healthy anatomical sagittal plane range of motion for these joints, respectively [30; 31; 32]. This is significantly more than other previously reported activities including cycling [33]. There are several limitations with the current study. Firstly, while the purpose of the HFgait modality is to be used by populations with or at risk of lower limb injury, the current study recruited healthy individuals. However, although this might be a limitation in the application of the findings since participants with lower limb impairments might not be able to perform the kinematic patterns described here, the current study describes the full kinematic potential of the HFgait exercise modality. This still can be used as a reference in the development of guidelines for exercise interventions and for preliminary studies in clinical populations. Another limitation of the current study is the lack of kinetic data that could highlight the differences between cycling and HFgait and provide further insights into possible injury mechanisms. This should be investigated in future studies. Finally, the current study investigated the kinematics of the HFgait at a comfortable speed for individuals that were just introduced to the movement. It is possible that as individuals become more familiar with the movement their kinematic patterns change or that they might be able to perform the movement at higher walking speeds. Therefore, changes in HFgait kinematics at different intensities and with different degrees of familiarity with this exercise modality should be investigated.