## 4 Discussion  
The purposes of this study were to analyze the influence of sex on the reliability of two TRE, compare the reliability of the DS-NDS in the assessment of two TRE, and study the relationship between the DS-NDS and the strength of two TREs. The results indicated that sex affected reliability in the HCW exercise but not in the LCW exercise. The DS-NDS did not affect the reliability of the measures in the HCW exercise. They did so in the LCW exercise, regardless of which manifestation of strength was measured. Considering sex and the dominant side, there were no differences in the HCW exercise, but differences were found in the LCW exercise. In females, the dominant side was more reliable when average strength was taken, and in males, the non-dominant side was more reliable when peak strength was taken. The strength in both exercises did not show significant differences in DS-NDS in almost all conditions. Furthermore, the strong correlations of DS-NDS were very large and extremely large. Few studies have evaluated STRM with a similar method. [PERSON] et al. (2017) obtained high reliability (ICC = 0.93-0.97) using a very similar protocol with a standing cable wood chop exercise and weight stack machine with incremental loads (20 to 55 Kg) [15]. [PERSON] et al. found high reliability (ICC = 0.83-0.98) when evaluating the STRM with the chop and lift test in a half-kneeling position and using a dynamometer and a pulley with 12% and 15% of the individual's body mass for the lift and chop, respectively [14]. However, no study assessed the STRM in isokinetic mode and in a functional way [7] as has been performed in the present study, which is the most novel. The most commonly used devices to assess STRM are isokinetic devices, load cells, and handheld dynamometers. Trunk strength assessments with isokinetic devices have high reliability, but their high cost and their very analytical evaluation of the muscle make them not transferable to daily activities or sporting gestures [27,28]. The trunk assessment with FEMD makes it possible to assess trunk reliability more functionally and closer to sporting gestures. Moreover, the advantage of FEMD over other devices is its ease of use, transportability, and low cost compared to isokinetic classic devices. The STRM influences daily activities and performances such as golf or kayaking [3,17]. In addition, the STRM is essential to provide stability to the spine, so knowing the reliability of the measurements helps both those in the clinical/medical field and coaches or physical trainers. A difference in the STRM reliability was found in HCW exercise, with females being more reliable. A study that assessed trunk rotator power analyzed the reliability by sex and found no differences, with ICCs ranging from 0.93 to 0.97 [11]. Nevertheless, [PERSON] et al. reported that males are more reliable than females when assessing trunk extensor strength and strength resistance [10]. This may suggest that sex may affect the reliability of trunk tests depending on which exercise is performed. In this case, no sexdifferences were found in reliability for the LWC exercise, although the lowest CV was found in the HCW exercise. On the other hand, the dominant side does not affect the reliability of the measurements in the HCW exercise, but it does in the LCW exercise. Furthermore, depending on which expression of strength is used, DS-NDS is more reliable. On the contrary, in previous studies in which the mean power between DS-NDS has been analyzed, all the ICCs have been around 0.90 [15]. Another study did not consider side laterality, assessing all subjects only on the right side [11]. Knowing the reliability of DS-NDS is very important for coaches and sports physicians. Sometimes the reliability of both sides is not measured. For example, when a training or rehabilitation program is applied, an improvement is sought according to the dominant side without considering the non-dominant side's value.