Functional Electromechanical Dynamometer Research Articles

Explanatory Model for Elite Canoeists’ Performance Using a Functional Electromechanical Dynamometer Based on Detected Lateral Asymmetry

Canoe modality in flatwater canoeing has a clear asymmetrical nature. This study aimed (1) to determine the magnitude and direction of neuromuscular properties, range of motion (ROM) and lower-limb strength asymmetries in female and male canoeists; (2) to establish sex-individualized asymmetry thresholds for canoeists’ neuromuscular properties, ROM and lower-limb strength; and (3) to determine the relationship of canoeists’ neuromuscular properties, ROM and lower-limb strength asymmetries with a specific canoe–dynamometer performance test. Twenty-one international canoeists were assessed through tensiomyography (TMG), ROM, lower-limb explosive strength, and a specific canoe incremental dynamometric test. The magnitude of asymmetry assessed through TMG and ROM was not modulated either by sex or performance level (international medal vs. non-medal). Females showed greater asymmetry than males on muscle tone of the erector spinae towards non-stroke side (22.75% vs. 9.72%) and the tibialis anterior (30.97% vs. 16.29%), and Fmax in explosive leg press (2.41% vs. 0.63%) towards the stroke side. International medalists showed greater asymmetry in semitendinosus contraction time towards non-stroke side (20.51% vs. 9.43%) and reached Vmax earlier in explosive leg press towards stroke side leg (19.20% vs. 9.40%). A greater asymmetry in Fmax and in Vm, and a smaller asymmetry in Tvmax and in leg press showed a small predictive capacity for canoeists’ performance on a specific canoe incremental dynamometry test. Reporting reference data from world-class canoeists’ asymmetries can be of great importance for coaches to periodically control lateral asymmetry.

Test-Retest Reliability of 3 Specific Strength Tests in Professional Handball Players.

Current devices to assess strength performance in handball may not be sufficiently sports-specific and reliable methods. Functional electromechanical dynamometry is a new technology that allows the development of accurate strength tests in athletes. To determine the absolute and relative reliability and to compare the reliability of the right and left side, and mean and peak force of 3 specific strength tests in handball players with a functional electromechanical dynamometer: unilateral pullover, standing lift, and step forward. Fourteen male handball players of the first Spanish division (28.79 [4.81]y; 10.38 [4.63]y of professional experience) performed a repeated-measurement design. Three testing sessions were performed (one per week). The first measurement consisted of 4 isometric tests (right and left unilateral pullover, and right and left standing lift) to obtain isometric peak force, and in the second and third sessions, 6 incremental tests until failure (right and left unilateral pullover, and right and left standing lift, right and left step forward) were performed. The tests provided high reliability or acceptable reliability for mean and peak strength of unilateral pullover, standing lift and step forward (intraclass correlation coefficient = .83-.97; coefficient of variation = 3.90-11.57). Effect side was negligible in any of the parameters, except for a small effect side in the left peak force for unilateral pullover and a small effect side on the left side for a step forward. Significant differences in reliability (coefficient of variation ratio > 1.15) were found between the right and left sides and peak and mean force in all exercises except peak force in unilateral pullover and step forward. These results confirm that the tests could be applied to assess physical performance in handball at the same time as regular gym training. Moreover, this is an excellent opportunity to individualize the player's weekly load.

Reliability of a handball specific strength test battery and the association with sprint and throwing performance in young handball players.

A greater motivation for coaches to be more involved in assessment could be the development of specific strength tests closer to specific handball tasks. Therefore, the aims were to determine the reliability of a handball specific strength test battery in young handball players using a functional electromechanical dynamometer (FEMD) and to evaluate the association between the strength test battery and performance measurements. Thirty-two young handball players (25% males and 75% females) performed a repeated-measurement design over four weeks. The players conducted one session per week, with each measurement consisting of two isometric tests to obtain isometric peak force, and four incremental tests. Moreover, performance handball tests (sprint and throwing velocity [TV]) were recorded. The reliability of the whole handball specific strength tests was very high for the peak and mean strength (ICC=0.70-0.85; CV=8.49-13.99; SEM=0.44-0.67 kg). The step forward had a moderate association with 5 to 10 meters' time. The highest correlation between TV<inf>mean</inf> was found with the peak strength of standing lift and between TV<inf>peak</inf> with peak strength of unilateral throw. The sprint total time could be explained by Body Mass Index and peak strength of the standing lift in the 40% and the TV<inf>peak</inf> could be explained by arm span and mean strength of the standing lift in the 68%. The high reliability for all exercises and the significant correlation with handball performance (sprint time and TV) allow us to include these tests in handball team evaluation and training.

Influence of trunk rotator strength on rotational medicine ball throwing performance.

The strength of the trunk musculature plays an essential role in performance. The aims of this study were to analyze the relationship between the strength of the trunk rotation muscles with rotational medicine ball throwing velocity and distance, to study differences between sex in rotational medicine ball throwing and to compare the asymmetries of trunk rotational strength and rotational medicine ball throwing. Thirty physically active college students participated on the study. Horizontal and low cable woodchop exercises were assessed with a functional electromechanical dynamometer and throwing was measured with a radar and a measuring tape. A Pearson's correlation coefficient was calculated for the relation between trunk rotational strength and rotational medicine ball throwing. Independent samples t-test was performed to determine the differences between sex in rotational medicine ball throwing and a paired samples t-test was performed to study the asymmetries. Large and very large correlations were obtained between trunk rotational strength and rotational medicine ball throwing (r=0.68-0.79). Significant differences and a large effect size were found between males and females for all throwing velocity and throwing distance variables (P<0.05; ES>0.90) and asymmetries in performance of mean velocity throwing (P=0.003; ES=-0.60) and peak velocity throwing (P=0.025; ES=-0.43). No significant differences were found between dominant and non-dominant side in any of the trunk rotator strength assessment conditions (P>0.05). There is a large or very large correlation between the STRM and the RMBT in all its modalities. Differences in strength were found between sexes, with no significant differences between dominant and non-dominant sides.

Strength Assessment of Trunk Rotator Muscles: A Multicenter Reliability Study.

Trunk rotator strength plays an important role in sports performance and health. A reliable method to assess these muscles with functional electromechanical dynamometer has not been described. Therefore, the objectives of this paper were (I) to explore the reliability of different strength variables collected in isokinetic and isometric conditions during two trunk rotator exercises, and (II) to determine the relationship of isometric and dynamic strength variables collected in the same exercise. A repeated measures design was performed to evaluate the reliability of the horizontal cable woodchop (HCW) and low cable woodchop (LCW) exercises. Reliability was assessed using t-tests of paired samples for the effect size, the standard error of measurement, the coefficient of variation (CV) and the intraclass correlation coefficient (ICC). The Pearson's (r) correlation coefficient was used to explore the association between isometric and isokinetic tests. HCW exercise is more reliable than LCW exercise in assessing trunk rotator muscles. The strength manifestation that should be used is the average strength, and the most reliable evaluation was the HCW at 0.40 m·s-1 concentric (ICC = 0.89; CV = 10.21%) and eccentric (ICC = 0.85; CV = 9.33%) contraction and the dynamic condition that most correlated with the isometric was LWC at 0.50 m·s-1 (r = 0.83; p < 0.01). HCW is a reliable exercise to measure trunk rotator muscles.

Relación entre la velocidad de lanzamiento y la fuerza específica evaluada a través de dinamometría electromecánica funcional (DEMF) en jugadores de balonmano

Objective. To study the relationship between the specific strength in handball, assessed with Functional Electromechanical Dynamometer (FEMD), and throwing velocity. Methods. Thirteen Spanish elite handball players were evaluated (28.77 ± 4.81 years, 90.19 ± 13.07 kg y 1.86 ± 0.10 m) during the preseason. A day of familiarization with the throwing velocity and strength test with FEMD was performed. One week later, the assessment of specific strength, including the upper and lower body (unilateral pullover test and step forward test) and throwing velocity was conducted by the subjects. Results. Significant correlations were found between (i) throwing velocity peak and isometric strength mean in unilateral pullover test with the dominant hand (r = 0.548, p = 0.05), and (ii) between throwing velocity peak and step forward test with the dominant leg (r = 0.628, p = 0.02). Conclusion. Training exercises closer to real game situations are positively related to performance enhancement in handball players. Therefore, the use of devices that allow the assessment and training at the same time in specific situations, should be extended in the sport coaches and researches.

Defensive two-step test in handball players: reliability of a new test for assessing displacement velocity

Los principales objetivos de este estudio fueron determinar la fiabilidad absoluta y relativa de la prueba de dos pasos (PDP) con un dinamómetro electromecánico funcional (DEMF) en la evaluación de la velocidad de desplazamiento. Participaron en este estudio dieciséis voluntarios varones jugadores de balonmano físicamente activos (edad 21,4 ± 2,1 años). Se utilizó un diseño de medidas repetidas para evaluar la velocidad de desplazamiento corporal con un 15% y un 30% de sobrecarga del peso corporal (SPC). Para calcular la velocidad de desplazamiento corporal se tomó la velocidad media de las tres repeticiones más altas y la velocidad máxima de las contracciones concéntricas. La fiabilidad se evaluó mediante pruebas t de muestras pareadas con el tamaño del efecto (ES), el coeficiente de variación (CV), el error estándar de medición (SEM) y el coeficiente de correlación intraclase (ICC), con intervalos de confianza del 95%. La fiabilidad absoluta proporcionó una repetitividad estable para el protocolo del 15% de SPC para la velocidad media y para la velocidad máxima en ambos protocolos, con un CV inferior al 10% en casi todos los casos. La fiabilidad relativa de los diferentes protocolos de velocidad para evaluar la velocidad media y la velocidad máxima fue aceptable (ICC entre 0,48 y 0,79). El PDP tiene una fiabilidad aceptable para la evaluación de la velocidad de desplazamiento en jugadores de balonmano utilizando un FEMD.

Bilateral index, power, force, and velocity during bench press with different loads in male handball players.

Bilateral index for upper limbs was determined for maximal force, speed and power in 18 male handball players. Variables were individually assessed with a functional electromechanical dynamometer during unilateral and bilateral bench press push-off for 40%, 60%, and 75% of the maximal isometric force. Limb dominance (symmetry indices) and load effects in the bilateral index were analysed. Bilateral index showed a bilateral deficit for power (range = -8.50 to -41.48) and velocity (range = -11.15 to -38.41), that increases with the load (p < 0.05). For maximum force, a bilateral facilitation (range = 2.26-5.57), which did not vary significantly as a function of load, was observed. Symmetry indices showed no association with the bilateral index (40% load: r = 0.45, 60% load: r = 0.05, 75% load: r = 0.39). These results contribute to understanding the phenomenon; however, individual-to-individual observation reflects that caution should be kept when assessing an individual athlete. In conclusion, bilateral deficit or facilitation for bench press depends on the variable considered, whereas its magnitude depends on the load. Moreover, limb dominance does not affect it. This finding must be regarded as a general trend, but a different situation may occur during the assessment of a particular athlete.

Influence of Sex and Dominant Side on the Reliability of Two Trunk Rotator Exercises

Background: A method to assess the influence of sex and side testing on trunk rotator muscles has not been described. The purpose was to analyze the influence of sex and dominant and non-dominant sides (DS-NDS) on the reliability of two trunk rotator exercises and to study the relationship between the DS-NDS of two trunk rotator strength exercises. Methods: The reliability of the horizontal cable woodchop (HCW) and low cable woodchop (LWC) exercises was studied using a test-retest design with 51 physically active students. Isokinetic and isometric strength were assessed with a functional electromechanical dynamometer. Results: There were significant differences in reliability between male and female HCW and no significant differences in reliability between the average of the DS-NDS in HCW and LCW. There were no significant differences between the DS-NDS in the sex of HCW, and the strength of the two exercises showed no significant differences except for two conditions assessed. Very large to extremely large correlations were observed between sides in the strength of two exercises (r = 0.71–0.91). Conclusions: This test is handy for physical trainers or coaches to know the strength of the trunk rotators of their athletes.

Strength level of elderly adults by manual and functional electromechanical dynamometer

Evaluar la fuerza de tren superior a través de los métodos de prueba de flexión de brazo, dinamometría manual y dinamómetro electromecánico funcional en adultos mayores independientes. Estudio transeccional, en 32 adulos mayores. Datos recolectados con dinamómetro manual, prueba de flexión de brazo y con el dinamómetro Electromecánico Funcional Dynasystem. Los resultados con la prueba de flexión de brazo mostraron los mayores índices de fuerza fueron entre 65 a 69 años (21.9 %; f = 7), en dinamometría manual los hombres presentaron baja fuerza (15.6%; f = 5) y en la DEMF-DYNASYSTEM el mayor porcentaje fue para 7 repeticiones (21.3%).

Dynamometric Strength Profile of Hip Muscles in Youth Soccer Players.

Soccer is the most widely practiced sport in the world, demanding high-speed activities such as jumps, sprints and changes of direction. Therefore, having optimal levels of muscle strength improves performance and reduces the injury rate. The objectives of our study were (i) to determine the dynamometric profile of hip muscle strength in young soccer players by position, evaluated at different isokinetic speeds, (ii) to describe the conventional and functional unilateral muscle strength ratios, (iii) to analyze the bilateral balance. Thirty-seven male soccer players (age 17.02 ± 0.92 years) participated in the study. Strength assessment was performed with a functional electromechanical dynamometer, and concentric and eccentric strength of abductors, adductors, extensors and hip flexors were measured bilaterally at 0.5 m/s and 1 m/s. For eccentric right hip abduction at 0.5 m/s, defenders are significantly stronger than midfielders (p = 0.013) and stronger than forwards (p = 0.140). For eccentric right hip adduction at 0.5 m/s, defenders are significantly stronger than midfielders (p = 0.005) and stronger than forwards (p = 0.253), as for eccentric right hip adduction at 1 m/s, defenders are significantly stronger than midfielders (p = 0.014) and stronger than forwards (p = 0.084). There is a significant effect for the conventional strength ratio of left abduction/adduction at 1 m/s. The conventional strength ratio of forwards is significantly higher than that of defenders (p = 0.045) and higher than that of midfielders (p = 0.152). Concentric and eccentric hip strength values differ according to playing position.

Test-Retest Reliability of the Functional Electromechanical Dynamometer for Squat Exercise.

the main objective of this study was to evaluate the test-retest reliability of two different functional electromechanical dynamometry (FEMD)-controlled squat training protocols. twenty-eight healthy young adults volunteered to participate in this study. They attended the laboratory on four different days and performed four sessions: two of three sets of 12 repetitions at 75% 1RM and two of three sets of 30 repetitions at 50% 1RM. The range of movement (ROM), mean dynamic strength (MDS), peak dynamic strength (PDS), mean velocity (MV), peak velocity (PV), mean potency (MP), peak potency (PP), work (W), and impulse (I) were recorded. To evaluate the reliability of FEMD, the intraclass correlation coefficient (ICC), standard error of measurement (SEM), and coefficient of variation (CV) were obtained. reliability was very high for ROM (CV: 3.72%, ICC: 0.95), MDS (CV: 1.09%, ICC: 1.00), PDS (CV: 1.97%, ICC: 1.00), and W (CV: 4.69%, ICC: 1.00) conditions at 50% 1RM and for ROM (CV: 3.90%, ICC: 0.95), MDS (CV: 0.52, ICC: 1.00), PDS (CV: 1.49%, ICC: 0.98), and W (CV: 4.14%, ICC: 1.00) conditions at 75% 1RM and high for the rest of variables at 50 and 75% 1RM. this study demonstrates that FEMD is a reliable instrument to measure ROM, MDS, PDS, MV, PV, PV, MP, MP, W, and I during both squat protocols (50 and 75% 1RM) in healthy young adults.

Muscle Quality and Functional and Conventional Ratios of Trunk Strength in Young Healthy Subjects: A Pilot Study.

Background: The trunk strength conventional ratio (CR) has been evaluated. However, the functional ratio and the ratio of strength to body weight (BW) or muscle mass (MM) have been poorly explored. Relative strength is a measure of muscle quality. Objectives: To analyze the trunk strength ratio normalized by BW and MM and compare the trunk’s conventional and functional ratios collected in isokinetic and isometric conditions. Methods: Twenty-seven healthy males (21.48 ± 2.08 years, 70.22 ± 7.65 kg) were evaluated for trunk isometric and isokinetic strength using a functional electromechanical dynamometer. Results: The extensor’s strength was greater than the flexors, with a CR of 0.41 ± 0.10 to 0.44 ± 0.10. Muscle quality was higher in eccentric contraction and high velocity for flexors and extensors. The functional flexor ratio (FFR) ranged between 0.41 ± 0.09 and 0.92 ± 0.27. The functional extensor ratio (FER) ranged between 2.53 ± 0.65 and 4.92 ± 1.26. The FFR and FER showed significant differences between velocities when considering the peak strength (p = 0.001) and mean strength (p = 0.001). Conclusions: Trunk extensors were stronger than the flexors; thus, the CR was less than one. Muscle quality was higher at a high velocity. Unlike CR, FFR and FER behaved differently at distinct velocities. This finding highlights the need to explore the behavior of the functional ratio in different populations.

A new reliable device to assess trunk extensors strength

Purpose: This study aimed to examine the reliability of trunk extensor strength assessment with a functional electromechanical dynamometer (FEMD). Methods: Thirty-one men performed strength assessment at different velocities (V) (V1 = 0.15 m·s−1, V2 = 0.30 m·s−1, V3 = 0.45 m·s−1) and range of movement (R) (R1 = 25% cm; R2 = 50% cm), and isometric contraction at 90º. Reliability was obtained through the intraclass correlation coefficient (ICC), typical error (TE), and coefficient of variation (CV). Results: The absolute reliability provided stable repeatability of the average eccentric strength in the V1R1 condition (CV = 9.52%) and the maximum eccentric strength in V1R1 (CV = 9.63%) and V2R2 (CV = 9.66%). The relative reliability of the trunk extensor’s average strength was good (ICC = 0.77–0.83) for concentric and good (ICC = 0.78–0.85) and moderate (ICC = 0.67–0.74) for eccentric contraction. Also, good (ICC = 0.77–0.81) and moderate (ICC = 0.55–0.74) reliability of the maximum strength were obtained for concentric and eccentric contraction. The most reliable manifestation to evaluate the concentric (CV = 11.33%) and eccentric (CV = 9.52%) strength was the average strength in the V1R1 condition and the maximum strength (CV = 10.29%) to isometric assessment. The average concentric strength in the V2R2 condition (r = 0.69) and the maximum eccentric strength in the V1R1 condition (r = 0.65) were the best related to the maximum isometric strength. Conclusions: FEMD is a highly reliable device to evaluate trunk extensors strength.

Test-retest reliability of a functional electromechanical dynamometer on swing eccentric hamstring exercise measures in soccer players.

BackgroundThe use of a functional electromechanical dynamometer (FEMD) has been proposed as a valid and effective tool to evaluate specific movement patterns. The aim of this study was to determine the reliability of FEMD on swing eccentric hamstring exercise (SEHE) measures in soccer players.MethodsNineteen federated male soccer players (20.74 ± 4.04 years) performed the SEHE at three different isokinetic velocities (20–40–60 cm/s). These evaluations were conducted in four sessions, two for familiarization and two for registration. The average and maximum load (N) of the three isokinetic velocities was calculated from the values obtained from the FEMD (Dynasystem®, Bangalore).ResultsThe main results of this research showed that the reliability was high for the average load in the condition of 40 cm/s, presenting the highest ICC value (0.94). For maximum load, reliability was high in the condition of 20 cm/s. The manifestation of the most reliable load was the maximum load (ICC = 0.91–0.87).ConclusionsFEMD (Dynasystem®, Bangalore) is a reliable device to evaluate the eccentric strength of the hamstring muscles in soccer players.

Concurrent validity and reliability of a functional electromechanical dynamometer to assess isometric mid-thigh pull performance

The aim of this study was to examine the concurrent validity and reliability of a functional electromechanical dynamometer (FEMD) to assess the isometric mid-thigh pull (IMTP) kinetic variables: peak force (PF), rate of force development (RFD), and time-specific force values (50-, 100-, 150-, and 200-ms). Twenty-seven male collegiate athletes (age: 22.9 ± 1.9 years; stature: 184.8 ± 10.4 cm; body mass: 84.2 ± 11.8 kg) performed four IMTP trials simultaneously on a force platform and the FEMD. The PF variables calculated from performance of the IMTP on both devices were reliable (CV &lt; 3%; ICC &gt; 0.90) and valid (bias &lt; 13.9 N; random error &lt; 52.1 N; r = 1.00), but they showed heteroscedasticity of the errors ( R2 &gt; 0.23). The RFD (CV &gt; 10.88%; ICC &lt; 0.76) and initial force (CV &gt; 8.81%; ICC &lt; 0.76) variables did not reach an acceptable reliability for any device, but they showed strong associations between them ( r range = 0.53–0.69). These results indicate that the FEMD is an acceptable alternative to assess athlete’s maximal force production (i.e. PF), but the data collected with FEMD and force plates should not be used interchangeably.

Test–Retest Reliability of Functional Electromechanical Dynamometer on Five Sit-to-Stand Measures in Healthy Young Adults

Background: The purpose of this study was to determine the reliability for the strength and movement velocity of the concentric phase from the five Sit-to-Stand (5STS), using three incremental loads measured by a functional electromechanical dynamometer (FEMD) in healthy young adults. Methods: The average and peak strength and velocity values of sixteen healthy adults (mean ± standard deviation (SD): age = 22.81 ± 2.13 years) were recorded at 5, 10 and 15 kg. To evaluate the reliability of FEMD, the intraclass correlation coefficient (ICC), standard error of measurement (SEM) and coefficient of variation (CV) were obtained. Results: Reliability was high for the 10 kg (CV range: 3.70–4.18%, ICC range: 0.95–0.98) and 15 kg conditions (CV range: 1.64–3.02%, ICC: 0.99) at average and peak strength, and reliability was high for the 5 kg (CV range: 1.71–2.84%, ICC range: 0.96–0.99), 10 kg (CV range: 0.74–1.84%, ICC range: 0.99–1.00) and 15 kg conditions (CV range: 0.79–3.11%, ICC range: 0.99–1.00) at average and peak velocity. Conclusions: The findings of this study demonstrate that FEMD is a reliable instrument to measure the average and peak strength and velocity values during the five STS in healthy young adults.

Effects of Pre-Activation with Variable Intra-Repetition Resistance on Throwing Velocity in Female Handball Players: a Methodological Proposal.

The purpose of this study was to investigate the acute effect of pre-activation with Variable Intra-Repetition Resistance and isometry on the overhead throwing velocity in handball players. Fourteen female handball players took part in the study (age: 21.2 ± 2.7 years, experience: 10.9 ± 3.5 years). For Post-Activation Potentiation, two pre-activation methods were used: (I) Variable Intra-Repetition Resistance: 1 x 5 maximum repetitions at an initial velocity of 0.6 m·s-1 and a final velocity of 0.9 m·s-1; (II) Isometry: 1 x 5 s of maximum voluntary isometric contraction. Both methods were "standing unilateral bench presses" with the dominant arm, using a functional electromechanical dynamometer. The variable analysed was the mean of the three overhead throws. Ball velocity was measured with a radar (Stalker ATS). The statistical analysis was performed using ANOVA with repeated measures. No significant differences were found for either method (variable resistance intra-repetition: p = 0.194, isometry: p = 0.596). Regarding the individual responses, the analysis showed that 86% of the sample increased throwing velocity with the variable resistance intra-repetition method, while 93% of the sample increased throwing velocity with the isometric method. Both the variable intra-repetition resistance and isometric methods show improvements in ball velocity in female handball players. However, the authors recommend checking individual responses, since the results obtained were influenced by the short rest interval between the pre-activation and the experimental sets.

Reliability and concurrent validity of a functional electromechanical dynamometer device for the assessment of movement velocity

The aims of the study were (i) to determine the reliability and concurrent validity of a functional electromechanical dynamometer (FEMD) to measure different isokinetic velocities, and (ii) to identify the real range of isokinetic velocity reached by FEMD for different prescribed velocities. Mean velocities were collected simultaneously with FEMD and a linear velocity transducer (LVT) in two sessions that were identical, consisting of 15 trials at five isokinetic velocities (0.40, 0.60, 0.80, 1.00, and 1.20 m·s−1) over a range of movement of 40 cm. The results obtained using each method were compared using Paired samples t-tests, Bland-Altman plots and the Pearson’s product–moment correlation coefficient, while the reliability was determined using the standard error of measurement and coefficient of variation (CV). The results indicate that the mean velocity values collected with FEMD and LVT were practically perfect correlations ( r &gt; 0.99) with low random errors (&lt;0.06 m·s−1), while mean velocity values were systematically higher for FEMD ( p &lt; 0.05). FEMD provided a high or acceptable reliability for mean velocity (CV ≤ 0.24%), time to reach the isokinetic velocity (CV range = 1.68%–9.70%) and time spent at the isokinetic velocity (CV range = 0.53%–8.94%). These results suggest that FEMD offers valid and reliable measurements of mean velocity during a fixed linear movement, as well as a consistent duration of the isokinetic phase. FEMD could be an appropriate device to evaluate movement velocity during linear movements. More studies are needed to confirm the reliability and validity of FEMD to measure different velocity metrics during more complex functional exercises.

INFLUENCE OF MAXIMAL ISOMETRIC STRENGTH ON 20-METER SPRINT TIME

ABSTRACT Introduction The squat is an exercise that is widely used for the development of strength in sports. However, considering that not all sports gestures are vertical, it is important to investigate the effectiveness of propulsive force stimuli applied in different planes. Objective The main purpose of this study was to determine the influence of maximum isometric force (MIF) exerted on starting blocks over performance in 5, 10 and 20-meter sprints. Methods Seven high-level male sprinters (mean age ± SD = 28 ± 5.77 years) participated in this study. The variables were: a) MIF in squats and on starting blocks (measured using a functional electromechanical dynamometer [FEMD]), b) time in 5, 10 and 20-m sprints and c) jump height (measured by the squat jump test). For data analysis, a Pearson correlation was performed between the different variables. The criteria for interpreting the strength of the r coefficients were as follows: trivial (&lt;0.1), small (0.1−0.3), moderate (0.3−0.5), high (0.5−0.7), very high (0.7−0.9), or practically perfect (&gt;0.9). The level of significance was p &lt; 0.05. Results There was very high correlation between MIF exerted on starting blocks and performance in the first meters of the sprint (5-m: r = -0.84, p = 0.01). However, there was small correlation between MIF in squats and performance in the first meters of the sprint (5-m: r = -0.22, p &lt; 0.62). Conclusion The MIF applied on starting blocks correlates very high with time in the first meters of the sprint in high-level athletes. In addition, the use of the FEMD provides a wide range of possibilities for evaluation and development of strength with a controlled natural movement. Level of evidence IV; Prognostic Studies - Case series.