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Background
Vertical jump height is widely used in health care and sports fields to assess muscle strength and power from lower limb muscle groups. Different approaches have been proposed for vertical jump height measurement. Some commonly used approaches need no sensor at all; however, these methods tend to overestimate the height reached by the su...
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... the proposed protocol, volunteers were asked to stand on a marker placed on the center of the mat and perform 3 medium-to-maximal effort CMJs, with their hands fixed at the waist, with 5 to 10 seconds rest between trials. This technique is depicted in Figure 5. After these jumps, the volunteers were asked to perform CMJAS this time, and following the same scheme. ...
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Citations
... Once calibrated, wearable inertial measurement units (IMUs) on multiple points of the body also assess balance by tracking accelerometry [12]. Pressure-Sensitive Mats (PSMs) also measure balance via CoP and have been used in balance studies [13][14][15], as well as many other applications covering vertical jump measurement, evaluating bodyweight exercise, sleep monitoring, and pressure sore prevention [16][17][18][19][20][21]. Instead of using load cells like a force plate, PSMs measure CoP by finding the average pressure location across a matrix of pressure sensors. ...
The accurate measurement of human balance is required in numerous analysis and training applications. Force plates are frequently used but are too costly to be suitable for home-based systems such as balance training. A growing body of research and commercial products use Pressure-Sensitive Mats (PSMs) for balance measurement. Low-cost PSMs are constructed with a piezoresistive material and use copper tracks as conductors. However, these lack accuracy, as they often have a low resolution and suffer from noise, non-repeatable effects, and crosstalk. This paper proposes novel algorithms that enable the Centre of Pressure (CoP) to be computed using low-cost PSM designs with significantly higher accuracy than is currently achievable. A mathematical model of a general low-cost PSM was developed and used to select the design of the PSM (track width and placement) that maximises CoP accuracy. These yield new optimal PSM geometries that decrease the mean absolute CoP error from 17.37% to 5.47% for an 8 × 8 sensor layout. Then, knowledge of the footprint was used to further optimise accuracy, showing a decrease in absolute error from 17.37% to 3.93% for an 8 × 8 sensor layout. A third algorithm was derived using models of human movement to further reduce measurement error.
... The sensor selection part was conducted according to the experiments to design and arrange the sensor array sections according to the zonal workspace ( Figure 4). Based on the author's tests and experiences, this process has been built along with zonal sensor performance hypotheses [34] with the criteria like availability, price, and performance [40,41]. The initial sensor selection process started with some studies on sensor types and responses. ...
... The layout of the sensor board was determined by considering the price, working area, and sensitivity based on ZP as follows. The FSR406 force sensor [46] was considered VG (very good, with excellent reliability [29,40]). This sensor needs a 10 K ohm resistor to sense the pressure for our aim in this study. ...
Getting proper rest is an essential issue, but it is neglected as the major component of every person’s overall health and well-being. Enough proper rest has a lot of proven health benefits. This paper aims at proposing a systematic framework to find the suitable pillows and mattresses for individuals to have proper rest and sleep. The proposed system includes a set of force-sensing resistors (FSR), thermal sensors, humidity-thermal sensors, and a central unit to process the acquired data. Customized software in LabVIEW is developed to monitor the results and ultimately identify the proper ergonomic mattresses and pillows for users. Initial experiments were performed based on zonal performance and multitasking to design, construct, and test each system as a novel hypothesis. The studies and tests were carried out in two steps. The first step included hardware testing and sensor arrangement, and the second step involved processing the acquired data to identify a good product. In this study, we propose a feasible framework to select convenient mattresses and pillows for each person.
... Many protocols exist in the literature to prove or validate the proposed systems. Leaps with and without countermovement [7][8][9][10], jumps with and without arm swing [11,12], drop jumps [13][14][15], single and double leg jumps [16], continuous jumps [17], squat jumps [7], and loaded squat jumps [18] are among the various types of jumps performed in those protocols. The height achieved by the user can be measured with any of these types of leaps, but the CMJ and SJ are the most widely utilized in all related work. ...
... Many protocols exist in the literature to prove or validate the proposed systems. Leaps with and without countermovement [7][8][9][10], jumps with and without arm swing [11,12], drop jumps [13][14][15], single and double leg jumps [16], continuous jumps [17], squat jumps [7], and loaded squat jumps [18] are among the various types of jumps performed in those protocols. The height achieved by the user can be measured with any of these types of leaps, but the CMJ and SJ are the most widely utilized in all related work. ...
... For instance, the researchers analyzed the long jump test and dynamic balance correlations on amateur rugby players [8], and Radhouane Haj Sassi et al. [29] examined the relationship to the free countermovement jump (FCMJ) and the 10m straight sprint (10mSS). The main indicators involved are jump height, peak force, peak power, rate of force development, and reactive strength index [2][3][4]7,19,20]. However, the correlation between jump height, EP, and FT has not been well investigated. ...
Background: The purpose of this study is threefold: (1) compare differences in countermovement jump (CMJ) variables and squat jump (SJ) variables in male track and field athletes; (2) explore the correlation of Fast Twitch Fibers (FT), Effect of Pre-stretch (EP) and other variables during the CMJ in male track and field athletes; (3) explore the correlation of SJ variables in male track and field athletes. Methods: 96 male university athletes (21.25 ± 1.04 years; 71.96 ± 8.58 kg; 180.05 ± 5.66 cm) in track and field volunteered to participate in this study. They are from Capital University of Physical Education and Sports, and all athletes are above the national standard at the second level. Subjects sequentially completed 3 CMJs and 3 SJs on the force plate. Throughout the entire range of motion, the CMJ and SJ were performed with both hands on the hips. In a laboratory, all of the individuals were assessed at the same time. SPSS 25.0 (Chicago, IL, USA) was used to run independent samples t-test and Pearson correlation analysis. Results: The vertical jump displacement (VJD) (p < 0.01), squat displacement (SD) (p < 0.01), peak velocity (PV) (p < 0.01), peak power (PP) (p < 0.05), average power (AP) (p < 0.01) were significantly higher during the CMJ than during the SJ. The peak force (PF) (p < 0.01) was significantly smaller during the CMJ than during the SJ. The FT and EP during the CMJ were associated with low test-retest reliability (coefficient of variation (CV): 9.73–8.86%). VJD, SD, PF, PP, and AP produced high test-retest reliability (CV: 2.29–4.48%) during both the CMJ and SJ movements. The correlation results were as follows, the VJD during the CMJ was significantly related to SD, PF, PP, AP (r = 0.21, r = 0.42, r = 0.8, r = 0.69, respectively). The PF during the CMJ was significantly related to PP and AP (r = 0.87, r = 0.72, respectively). The PV during the CMJ was significantly related to PP and AP (r = 0.63, r = 0.79, respectively). During the CMJ, there were significant connections between PP and AP (r = 0.94). Except for SD showed no significant relationships and the results for the correlation of other variables were the same as CMJ during the SJ. Furthermore, the Fast Twitch Fibers (FT) during the CMJ was significantly related to PP and AP (r = 0.49, r = 0.46, respectively). The Effect of Pre-stretch (EP) during the CMJ was significantly related to PV, PP, AP and FT (r = 0.36, r = 0.24, r = 0.27, r = 0.22, respectively). Conclusions: Our results indicate that both FT and EP were highly significantly correlated with PP in CMJ, and both FT and EP were significantly correlated with AP in CMJ. In addition, FT and EP data have good reliability. It means that FT and EP may be important indicators of lower limb strength in male track and field athletes under certain conditions. This will inform the training of male track and field athletes.
... The vertical jump was widely used in health care and athletes to measure lower limb muscle strength and power (Vanegas et al., 2021). The subjects' arms were allowed to move freely during the vertical jump assessment (Petrigna et al., 2019). ...
Promoting a high level of strength, power, and postural control in specific playing positions is crucial throughout the puberty phase in young football players. This study explored peak power, lower limb explosive strength, and balance performance among youth football players across their playing positions. Forty-three young male football players (age: 15.81±1.33 years) participated, categorized into four positions: 5 goalkeepers, 12 defenders, 20 midfielders, and 6 forwards. Significant differences were observed in peak power output among playing positions (p=0.003, η²=0.226), with forwards superior over midfielders (p=0.011). However, no meaningful disparities were found in vertical jump characteristics. Variations in center of body pressure sway speed medial-lateral direction were identified for nondominant and dominant leg (p=0.025, η²=0.211; p=0.033, η²=0.198), with the lower sway speed in goalkeepers (p=0.022) in comparison with forwards (p=0.040). However, the study found no significant differences in the other characteristics of static balance performance, nor in the dynamic balance. In conclusion, the study emphasizes significant variations in peak power output across player positions but not for lower limb explosive strength and balance performance among groups.
Wearable sensing fabrics have great potential for applications such as human-computer interaction, motion monitoring, and human shape reconstruction. However, existing fabric sensors tend to sacrifice wearing comfort for sensing functionality, which restricts their application scenarios and hampers long-term usability due to poor wearability. To address this challenge, a novel fabric structure was designed to work with a flat knitting machine to realize a single-ply and knit-only textile pressure-sensing matrix. The sensing fabric has a sensing range of 0.255 to 35.65 kPa, with a maximum sensitivity of 0.72 kPa
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. Although its sensing performance fluctuates under fatigue testing, washing and drying, folding, and stretching operations, it still supports use. It also has thermal comfort performance comparable to a regular T-shirt. We produced a pair of sensing shorts containing 256 sensing units and collected a total of 224,483 frames of data containing 18 postures from 6 participants. Posture classification using ResNet-18 achieved 88.2% accuracy.
