Research in Sport Medicine and Technology

---

The main goal of this research was to design and evaluate the features of a "home-based weightless fitness device with digital adjustment" for performing muscular exercises in a home environment. To achieve this goal, a combined quantitative and qualitative approach was employed, and a detailed assessment of the device's performance was conducted. In the initial stage, existing fitness equipment, resistance training methods, and technological advancements were investigated. This review provided fundamental information for the initial design of the device. Subsequently, using design software such as Rhino Cross 6 and AutoCAD 2018, precise three-dimensional models and initial prototypes were created. To validate the device's resistance, a digital force gauge was utilized, measuring the displayed force in eight different settings with the resistance adjusted on the device, allowing for the calculation of device deviation from standard and error margin. Furthermore, to assess the device's reliability three seated movements—leg press extension, seated chest press, and seated front raise bicep curl—, each performed with eight consecutive repetitions using a 10-kilogram weight. The results of Pearson's correlation coefficient (0.9) showed that the instrument has high reliability. Also, the results of intra-correlation reliability coefficient (0.8) showed that the device has good reliability and high accuracy in the produced resistance in different movements and repetitions. Ultimately, this research introduces an effective tool for muscular exercises in a home setting. With its precise resistance adjustment capability and versatility in exercise options, the device empowers athletes to perform exercises with greater precision. Overall, this study yields practical and implementable results, potentially playing a crucial role in enhancing the health and fitness of athletes and the general community.
 
 

---

One of the most common abnormalities in the lower extremity, is the flexible flat foot. Pes planus is a condition where medial longitudinal is flatter than normal and the entire sole of the foot comes into near complete or complete contact with ground and causes distortions in the structures of the skeletal parts of the foot. The purpose of this study was the effect of six weeks of local and comprehensive corrective exercises on proprioception, balance and ankle navicular drop in 10-18 years old female with flexible flat foot deformity. This research was quasi-experimental study performed in two phases: pre-test and post-test. Fifty one female with flexible flat foot postures entered the study as subject. They were randomly divided into 2 experimental groups (local and comprehensive) and 1 group control. As one of the inclusion criteria, a navicular drop test was performed for subject to assess the condition of the foot posture. The experimental group performed corrective exercise for 6 weeks (3 sessions per week for 30 minutes) while control group performed the routine exercise. Ankle proprioception, balance and navicular drop was evaluated before and after the interventions. Statistical analysis was performed in SPSS software version 26. A covariance analysis test was use to evaluate the between-group difference, and paired sample test was used to evaluate the within-group changes. This study's finding showed that the corrective exercise group in the post-test had a better performance than pre-test in proprioception, navicular drop and balance (P=0.000) but in the control group, no significant difference was observed between the two stages of the test (P>0.05). it was also observed in the comparison between groups that in the post-test in the variables of the proprioception, navicular drop and balance of the experimental group achieved better results than the control group (P>0.05). This study show that six weeks of local and comprehensive corrective exercises has significantly improved proprioception, navicular drop and balance in 10-18 years old female with flexible flat foot. According to the results obtained in this study, it seems that corrective exercises can be used in this group to improve proprioception, static balance and posture

---

Nowadays there is no specific and effective standard for evaluating the helmets in martial arts which it has caused a lot of brain damages. The purpose of this study was designing and modeling a helmet assessment machine in martial arts, based on dynamic’s parameters and criteria. SolidWorks, Adams and Catia softwares were used for designing this machine. Also, In order to build this machine, an artificial head that equipped with force and acceleration sensors and a mechanical arm for applying impact to the head were used. The validation of the machine was done by comparing its results (impact force, linear acceleration and rotational acceleration) with the results obtained from the simulated model in the computer. The Pearson correlation coefficient of 0.9 that obtained from this comparison indicates that the results of this machine are correct. To confirm the reliability of the machine, an Intraclass Correlations was used, the results showed values of 0.7 and greater than that and it also confirmed the appropriate repeatability of the machine. According to the results of this study, due to the considering the important parameters of linear and rotational acceleration and the impact force in evaluating helmets and investigating the mechanism of head injury in the conditions close to competition ones, the device can be an appropriate equipment for more accurate measurement of helmets in martial arts.