scholarly journals Force-Sensitive Mat for Vertical Jump Measurement to Assess Lower Limb Strength: Validity and Reliability Study (Preprint)

2021 ◽  
Author(s):  
Erik Vanegas ◽  
Yolocuauhtli Salazar ◽  
Raúl Igual ◽  
Inmaculada Plaza
Keyword(s):  
Lower Limb ◽  
Vertical Jump ◽  
Sampling Frequency ◽  
Coefficient Of Determination ◽  
Jump Height ◽  
Countermovement Jump ◽  
Raw Data ◽  
Vertical Jump Height ◽  
High Sampling ◽  
The Impact

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 subjects. There are also novel systems using different kind of sensors like force-sensitive resistors, capacitive sensors, and inertial measurement units, among others, to achieve more accurate measurements. OBJECTIVE The objective of this study is twofold. The first objective is to validate the functioning of a developed low-cost system able to measure vertical jump height. The second objective is to assess the effects on obtained measurements when the sampling frequency of the system is modified. METHODS The system developed in this study consists of a matrix of force-sensitive resistor sensors embedded in a mat with electronics that allow a full scan of the mat. This mat detects pressure exerted on it. The system calculates the jump height by using the flight-time formula, and the result is sent through Bluetooth to any mobile device or PC. Two different experiments were performed. In the first experiment, a total of 38 volunteers participated with the objective of validating the performance of the system against a high-speed camera used as reference (120 fps). In the second experiment, a total of 15 volunteers participated. Raw data were obtained in order to assess the effects of different sampling frequencies on the performance of the system with the same reference device. Different sampling frequencies were obtained by performing offline downsampling of the raw data. In both experiments, countermovement jump and countermovement jump with arm swing techniques were performed. RESULTS In the first experiment an overall mean relative error (MRE) of 1.98% and a mean absolute error of 0.38 cm were obtained. Bland-Altman and correlation analyses were performed, obtaining a coefficient of determination equal to <i>R</i><sup>2</sup>=.996. In the second experiment, sampling frequencies of 200 Hz, 100 Hz, and 66.6 Hz show similar performance with MRE below 3%. Slower sampling frequencies show an exponential increase in MRE. On both experiments, when dividing jump trials in different heights reached, a decrease in MRE with higher height trials suggests that the precision of the proposed system increases as height reached increases. CONCLUSIONS In the first experiment, we concluded that results between the proposed system and the reference are systematically the same. In the second experiment, the relevance of a sufficiently high sampling frequency is emphasized, especially for jump trials whose height is below 10 cm. For trials with heights above 30 cm, MRE decreases in general for all sampling frequencies, suggesting that at higher heights reached, the impact of high sampling frequencies is lesser.

scholarly journals Force-Sensitive Mat for Vertical Jump Measurement to Assess Lower Limb Strength: Validity and Reliability Study

10.2196/27336 ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. e27336
Author(s):  
Erik Vanegas ◽  
Yolocuauhtli Salazar ◽  
Raúl Igual ◽  
Inmaculada Plaza
Keyword(s):  
Lower Limb ◽  
Vertical Jump ◽  
Sampling Frequency ◽  
Coefficient Of Determination ◽  
Jump Height ◽  
Countermovement Jump ◽  
Raw Data ◽  
Vertical Jump Height ◽  
High Sampling ◽  
The Impact

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 subjects. There are also novel systems using different kind of sensors like force-sensitive resistors, capacitive sensors, and inertial measurement units, among others, to achieve more accurate measurements. Objective The objective of this study is twofold. The first objective is to validate the functioning of a developed low-cost system able to measure vertical jump height. The second objective is to assess the effects on obtained measurements when the sampling frequency of the system is modified. Methods The system developed in this study consists of a matrix of force-sensitive resistor sensors embedded in a mat with electronics that allow a full scan of the mat. This mat detects pressure exerted on it. The system calculates the jump height by using the flight-time formula, and the result is sent through Bluetooth to any mobile device or PC. Two different experiments were performed. In the first experiment, a total of 38 volunteers participated with the objective of validating the performance of the system against a high-speed camera used as reference (120 fps). In the second experiment, a total of 15 volunteers participated. Raw data were obtained in order to assess the effects of different sampling frequencies on the performance of the system with the same reference device. Different sampling frequencies were obtained by performing offline downsampling of the raw data. In both experiments, countermovement jump and countermovement jump with arm swing techniques were performed. Results In the first experiment an overall mean relative error (MRE) of 1.98% and a mean absolute error of 0.38 cm were obtained. Bland-Altman and correlation analyses were performed, obtaining a coefficient of determination equal to R2=.996. In the second experiment, sampling frequencies of 200 Hz, 100 Hz, and 66.6 Hz show similar performance with MRE below 3%. Slower sampling frequencies show an exponential increase in MRE. On both experiments, when dividing jump trials in different heights reached, a decrease in MRE with higher height trials suggests that the precision of the proposed system increases as height reached increases. Conclusions In the first experiment, we concluded that results between the proposed system and the reference are systematically the same. In the second experiment, the relevance of a sufficiently high sampling frequency is emphasized, especially for jump trials whose height is below 10 cm. For trials with heights above 30 cm, MRE decreases in general for all sampling frequencies, suggesting that at higher heights reached, the impact of high sampling frequencies is lesser.

scholarly journals Effects of ethnicity on the relationship between vertical jump and maximal power on a cycle ergometer

2016 ◽  
Vol 51 (1) ◽  
pp. 209-216 ◽  
Author(s):  
Majdi Rouis ◽  
Laure Coudrat ◽  
Hamdi Jaafar ◽  
Elvis Attiogbé ◽  
Henry Vandewalle ◽  
...  
Keyword(s):  
Body Mass ◽  
High Reliability ◽  
Vertical Jump ◽  
Linear Regression Analysis ◽  
Body Height ◽  
Lower Limbs ◽  
Jump Height ◽  
Maximal Power ◽  
Vertical Jump Height ◽  
The Impact

Abstract The aim of this study was to verify the impact of ethnicity on the maximal power-vertical jump relationship. Thirty-one healthy males, sixteen Caucasian (age: 26.3 ± 3.5 years; body height: 179.1 ± 5.5 cm; body mass: 78.1 ± 9.8 kg) and fifteen Afro-Caribbean (age: 24.4 ±2.6 years; body height: 178.9 ± 5.5 cm; body mass: 77.1 ± 10.3 kg) completed three sessions during which vertical jump height and maximal power of lower limbs were measured. The results showed that the values of vertical jump height and maximal power were higher for Afro-Caribbean participants (62.92 ± 6.7 cm and 14.70 ± 1.75 W∙kg-1) than for Caucasian ones (52.92 ± 4.4 cm and 12.75 ± 1.36 W∙kg-1). Moreover, very high reliability indices were obtained on vertical jump (e.g. 0.95 < ICC < 0.98) and maximal power performance (e.g. 0.75 < ICC < 0.97). However, multiple linear regression analysis showed that, for a given value of maximal power, the Afro-Caribbean participants jumped 8 cm higher than the Caucasians. Together, these results confirmed that ethnicity impacted the maximal power-vertical jump relationship over three sessions. In the current context of cultural diversity, the use of vertical jump performance as a predictor of muscular power should be considered with caution when dealing with populations of different ethnic origins.

Influence of a preventive training program on lower limb kinematics and vertical jump height of male volleyball athletes

2013 ◽  
Vol 14 (1) ◽  
pp. 35-43 ◽  
Author(s):  
Gustavo Leporace ◽  
Jomilto Praxedes ◽  
Glauber Ribeiro Pereira ◽  
Sérgio Medeiros Pinto ◽  
Daniel Chagas ◽  
...  
Keyword(s):  
Training Program ◽  
Lower Limb ◽  
Vertical Jump ◽  
Jump Height ◽  
Vertical Jump Height ◽  
Limb Kinematics ◽  
Lower Limb Kinematics

scholarly journals Both Caffeine and Placebo Improve Vertical Jump Performance Compared With a Nonsupplemented Control Condition

2020 ◽  
pp. 1-4 ◽  
Author(s):  
Jozo Grgic ◽  
Sandro Venier ◽  
Pavle Mikulic
Keyword(s):  
Power Output ◽  
Vertical Jump ◽  
Gelatin Capsule ◽  
Jump Height ◽  
Countermovement Jump ◽  
Maximal Power ◽  
Maximal Power Output ◽  
Jump Performance ◽  
Vertical Jump Height ◽  
And Control

Purpose: To compare the acute effects of caffeine and placebo ingestion with a control condition (ie, no supplementation) on vertical jump performance. Methods: The sample for this study consisted of 26 recreationally trained men. Following the familiarization visit, the subjects were randomized in a double-blind manner to 3 main conditions: placebo, caffeine, and control. Caffeine was administered in the form of a gelatin capsule in the dose of 6 mg·kg body weight−1. Placebo was also administered in the form of a gelatin capsule containing 6 mg·kg−1 of dextrose. Vertical jump performance was assessed using a countermovement jump performed on a force platform. Analyzed outcomes were vertical jump height and maximal power output. Results: For vertical jump height, significant differences were observed between placebo and control conditions (g = 0.13; 95% confidence interval [CI], 0.03–0.24; +2.5%), caffeine and control conditions (g = 0.31; 95% CI, 0.17–0.50; +6.6%), and caffeine and placebo conditions (g = 0.19; 95% CI, 0.06–0.34; +4.0%). For maximal power output, no significant main effect of condition (P = .638) was found. Conclusions: Ingesting a placebo or caffeine may enhance countermovement jump performance compared with the control condition, with the effects of caffeine versus control appearing to be greater than the effects of placebo versus control. In addition, caffeine was ergogenic for countermovement jump height compared with placebo. Even though caffeine and placebo ingestion improved vertical jump height, no significant effects of condition were found on maximal power output generated during takeoff.

scholarly journals Strength and vertical jump performance changes in elite male volleyball players during the season (Cambios en el rendimiento en fuerza y salto vertical en jugadores de élite masculinos de voleibol durante la temporada)

Retos ◽  
2018 ◽  
pp. 291-294
Author(s):  
Miguel Sánchez Moreno ◽  
Carlos García Asencio ◽  
Juan José González Badillo ◽  
David Díaz Cueli
Keyword(s):  
Beneficial Effect ◽  
Strength Training ◽  
Physical Performance ◽  
Lower Limb ◽  
Vertical Jump ◽  
Jump Height ◽  
Jump Performance ◽  
Vertical Jump Height ◽  
Competitive Season ◽  
Volleyball Players

Abstract. This study aimed to analyze the effect of strength training on physical performance in elite male volleyball players during the competitive season. Athletes were assessed at the start of season (SS), midpoint of the competitive season (MS), and at the end of the season (ES). Significant increases were observed in vertical jump height (CMJ), jump squat height (JS) and mean propulsive velocity (MPV) from SS to ES (P < 0.05). Likely beneficial increases were observed on CMJ from SS to MS, on JS from SS to MS and from MS to ES. In addition, likely beneficial effect was found on MPV from MS to ES. Over the full season (SS to ES), very likely beneficial effect was observed on CMJ, MPV and JS. In conclusion, increase in strength of lower limb and vertical jump can be achieved in professional volleyball players over a full playing season. Resumen. El objetivo del estudio fue analizar los efectos de un programa de entrenamiento de fuerza sobre el rendimiento en la fuerza del miembro inferior y la capacidad de salto vertical en jugadores de voleibol masculinos durante la temporada de competición. Los atletas fueron evaluados al inicio (SS), a la mitad (MS) y al final de la temporada (ES). Se observaron aumentos significativos en la altura del salto vertical (CMJ), del salto con cargas (JS) y en la velocidad media propulsiva (MPV) alcanzada con las cargas comunes en el ejercicio de sentadillas entre SS y ES (P < 0.05). El análisis basado en la magnitud del cambio reveló un aumento probable en CMJ de SS a MS, y en JS de SS a MS y de MS a ES. Además, un incremento probable se encontró en MPV de MS a ES. Durante la temporada completa (SS a ES), se observó un aumento muy probable en CMJ, en MPV y JS. En conclusión, se puede lograr un aumento en la fuerza de la extremidad inferior y el salto vertical en jugadores profesionales de voleibol durante una temporada de juego completa.

scholarly journals Physical Performance Improves With Time and a Functional Knee Brace in Athletes After ACL Reconstruction

2020 ◽  
Vol 8 (8) ◽  
pp. 232596712094425
Author(s):  
Laura C. Dickerson ◽  
Alexander T. Peebles ◽  
Joseph T. Moskal ◽  
Thomas K. Miller ◽  
Robin M. Queen
Keyword(s):  
Physical Performance ◽  
Performance Measures ◽  
Repeated Measures ◽  
Vertical Jump ◽  
Performance Testing ◽  
Performance Measure ◽  
Jump Height ◽  
Knee Brace ◽  
Vertical Jump Height ◽  
The Impact

Background: Athletes who return to sport (RTS) after anterior cruciate ligament reconstruction (ACLR) often have reduced physical performance and a high reinjury rate. Additionally, it is currently unclear how physical performance measures can change during the RTS transition and with the use of a functional knee brace. Purpose/Hypothesis: The purpose of this study was to examine the effects of time since surgery (at RTS and 3 months after RTS) and of wearing a brace on physical performance in patients who have undergone ACLR. We hypothesized that physical performance measures would improve with time and would not be affected by brace condition. Study Design: Controlled laboratory study. Methods: A total of 28 patients who underwent ACLR (9 males, 19 females) completed physical performance testing both after being released for RTS and 3 months later. Physical performance tests included the modified agility t test (MAT) and vertical jump height, which were completed with and without a knee brace. A repeated-measures analysis of variance determined the effect of time and bracing on performance measures. Results: The impact of the knee brace was different at the 2 time points for the MAT side shuffle ( P = .047). Wearing a functional knee brace did not affect any other physical performance measure. MAT times improved for total time ( P < .001) and backpedal ( P < .001), and vertical jump height increased ( P = .002) in the 3 months after RTS. Conclusion: The present study showed that physical performance measures of agility and vertical jump height improved in the first 3 months after RTS. This study also showed that wearing a knee brace did not hinder physical performance. Clinical Relevance: Wearing a functional knee brace does not affect physical performance, and therefore a brace could be worn during the RTS transition without concern. Additionally, physical performance measures may still improve 3 months past traditional RTS, therefore justifying delayed RTS.

scholarly journals The Comparative Effects of Ankle Bracing on Functional Performance

2018 ◽  
Vol 27 (5) ◽  
pp. 491-502
Author(s):  
Thomas M. Newman ◽  
Giampietro L. Vairo ◽  
William E. Buckley
Keyword(s):  
Range Of Motion ◽  
Performance Measures ◽  
Clinical Decision Making ◽  
Functional Performance ◽  
Vertical Jump ◽  
Ankle Sprains ◽  
Jump Height ◽  
Physically Active ◽  
Vertical Jump Height ◽  
The Impact

Ankle sprains represent a common musculoskeletal injury that clinicians are tasked with preventing and treating. Because of the prevalence of this injury, ankle braces have been designed to prophylactically protect the joint and reduce the incidence of repetitive sprains. Although an abundance of literature exists focusing on the efficacy of braces in preventing ankle sprains in young, healthy, and physically active populations, there is a scarcity of evidence specific to the impact of these apparatuses on functional performance; therefore, the purpose of this critically appraised topic (CAT) is to investigate the effects of ankle braces on functional performance measures in such individuals. The outcomes of this CAT will assist sport rehabilitation specialists with informed clinical decision making in managing young, healthy, and physically active populations using ankle braces. Do ankle braces hinder functional performance measures when compared with an unbraced condition in a young, healthy, and physically active population? A minimum of level II evidence research studies were surveyed for this CAT. For this CAT, 1 randomized controlled trial and 3 prospective cohort studies were selected. One study found a statistically significant main effect of increased agility run times while participants wore ankle braces. Another study demonstrated a statistically significant decrease in vertical jump height and ankle range of motion while wearing braces. No other statistically significant findings were reported among studies comparing unbraced with braced conditions. Current data indicate that young, healthy, and physically active individuals may experience varied performance effects when executing specific functional performance tasks while wearing ankle braces. In general, bracing does not appear to significantly impair performance on most functional tasks; however, decrements were noted to increases in agility run time and decreases in vertical jump height. Subsequent analysis indicated that a brace may result in decreased ankle plantarflexion, dorsiflexion, eversion, and inversion range of motion, which may underpin noted performance deficits.

scholarly journals Effects of Percutaneous Electrical Nerve Stimulation on Countermovement Jump and Squat Performance Speed in Male Soccer Players: A Pilot Randomized Clinical Trial

2021 ◽  
Vol 10 (4) ◽  
pp. 690
Author(s):  
Gracia María Gallego-Sendarrubias ◽  
José Luis Arias-Buría ◽  
Edurne Úbeda-D’Ocasar ◽  
Juan Pablo Hervás-Pérez ◽  
Manuel Antonio Rubio-Palomino ◽  
...  
Keyword(s):  
Training Program ◽  
Nerve Stimulation ◽  
Vertical Jump ◽  
Sport Performance ◽  
Flight Time ◽  
Soccer Players ◽  
Jump Height ◽  
Countermovement Jump ◽  
Electrical Nerve Stimulation ◽  
Vertical Jump Height

It has been suggested that Percutaneous Electrical Nerve Stimulation (PENS) can increase muscle strength. No previous study has investigated changes in performance in semiprofessional soccer players. This study compares the effects of adding two sessions of PENS to a training program versus the single training program over sport performance attributes (e.g., jump height and squat speed) in healthy soccer players. A cluster-randomized controlled trial was conducted on twenty-three semiprofessional soccer players who were randomized into an experimental (PENS + training program) or control (single training program) group. The training program consisted of endurance and strength exercises separated by 15-min recovery period, three times/week. The experimental group received two single sessions of PENS one-week apart. Flight time and vertical jump height during the countermovement jump and squat performance speed were assessed before and after each session, and 30 days after the last session. Male soccer players receiving the PENS intervention before the training session experienced greater increases in the flight time, and therefore, in vertical jump height, after both sessions, but not one month after than those who did not receive the PENS intervention (F = 4.289, p = 0.003, η 2 p: 0.170). Similarly, soccer players receiving the PENS intervention experienced a greater increase in the squat performance speed after the second session, but not after the first session or one month after (F = 7.947, p < 0.001, η 2 p: 0.275). Adding two sessions of ultrasound-guided PENS before a training strength program improves countermovement jump and squat performance speed in soccer players.

Physical and performance characteristics related to starter status, position, and division in Japanese collegiate American-football players

2021 ◽  
pp. 1-8
Author(s):  
Junta Iguchi ◽  
Minoru Matsunami ◽  
Tatsuya Hojo ◽  
Yoshihiko Fujisawa ◽  
Kenji Kuzuhara ◽  
...  
Keyword(s):  
Performance Test ◽  
Vertical Jump ◽  
American Football ◽  
Football Players ◽  
Jump Height ◽  
Test Results ◽  
Repetition Maximum ◽  
Vertical Jump Height ◽  
Division 1 ◽  
And Performance

BACKGROUND: Few studies have investigated the variations in body composition and performance in Japanese collegiate American-football players. OBJECTIVE: To clarify what characterizes competitors at the highest levels – in the top division or on the starting lineup – we compared players’ body compositions and performance test results. METHODS: This study included 172 players. Each player’s body composition and performance (one-repetition maximum bench press, one-repetition maximum back squat, and vertical jump height) were measured; power was estimated from vertical jump height and body weight. Players were compared according to status (starter vs. non-starter), position (skill vs. linemen), and division (1 vs. 2). Regression analysis was performed to determine characteristics for being a starter. RESULTS: Players in higher divisions and who were starters were stronger and had more power, greater body size, and better performance test results. Players in skill positions were relatively stronger than those in linemen positions. Vertical jump height was a significant predictor of being a starter in Division 1. CONCLUSION: Power and vertical jump may be a deciding factor for playing as a starter or in a higher division.

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