## 4 Discussion
### Hip Joint and Hand Pushing Forces  
The maximum heel force in hip extension in the TCC group was significantly lower than in the NTCC group by roughly \(-9.3\%\), but there were no significant differences in toe maximum force in hip flexion between the two groups. There were not any significant differences between the two groups in the hand maximum forces either in the shoulder joint of \(90^{\circ}\) or in the elbow joint of \(90^{\circ}\) as in Table 4. These results indicate that the TCC exercise had no effect on the upper limbs and joints in terms of wrist forward flexion strength. In the literature, there is little research on the hand pushing forces; thus, it is impossible to compare our results with others.  
One of the most interesting findings in this study was that a significant difference was found for the heel forces in hip extension between the two groups. The NTTC participants had greater heel forces in the hip extension than the TCC group. It may be the reason that TCC players emphasize movements with the hip flexion muscles rather than hip extension muscles during TCC.  
Another interesting finding is that there was no significant effect of TCC practice on the hand pushing forces in either the shoulder or elbow joints of \(90^{\circ}\).  
It should be noted that previous studies used different means to measure TCC muscle or joint strength, e.g., a hand-held dynamometer to measure grip forces, a jump to estimate joint powers or various types of isokinetic dynamometers to measure the joint strengths as torque. These methods had different types of outcomes, e.g., torque (Nm) from isokinetic dynamometers with different joint angles. In our study, limb/joint strength is measured as force (N) directly. As the device used in measurements and the variables (and units) used in this study are different from those from the previous studies, it is difficult to compare our results with previous ones. That said, we estimate the joint moment using the force and leg length and then compare our numeric outcomes with previously published studies. Using the estimated moment, the knee extension moments are \(77\pm 2.4\) (Mean \(\pm\) Standard error of mean) in TCC and \(71\pm 2.15\) Nm in NTCC, and the knee flexion moments are \(34\pm 1.5\) and \(41\pm 1.4\) Nm, respectively. These results are slightly lower than those in [PERSON] et al. (2002) [PERSON] et al. (2002) and similar to [PERSON] et al. (2014) [PERSON] et al. (2014). Nevertheless, most of the previous studies reported that knee exteriors had higher strength in the TCC than in control groups, which is the same as what we observed from this study.  
Recently, some studies have investigated TCC in various aspects. [PERSON] et al. (2020) reported that the TCC group was able to jump \(44\%\) higher than the NTCC group. During the jumping, the TCC group also showed a lower Centre of Mass (CoM), larger Range of Motion (RoM) in joint angle and higher joint moment and power than NTCC [PERSON] et al. (2022) compared four age groups during jumping and found that the jumping heights decreased with aging [PERSON] et al. (2022). [PERSON] et al. (2022) reported that the knee extensor and flexor in children with developmental coordination disorder were improved after 3 months of TCC exercise [PERSON] et al. (2022). [PERSON] (2022) showed that the muscle functions in sedentary older adults with chronic condition(s) were improved with TCC [PERSON] et al. (2022) observed that the foot pressures in participants with knee osteoarthritis were changed after 6 months of TCC [PERSON] et al. (2022). These studies obtained some meaningful results. However, the strengths in the joints and limbs between TCC and NTCC have not been directly measured and compared. Therefore, this present study would fill the research gap.