Dr. Ulloa-Diaz, David

Aim. To determine the absolute and relative reliability of functional trunk tests, using a functional electromechanical dynamometer to evaluate the isokinetic strength of trunk flexors and to determine the most reliable assessment condition, in order to compare the absolute and relative reliability of mean force and peak force of trunk flexors and to determine which isokinetic condition of evaluation is best related to the maximum isometric. Methods. Test-retest of thirty-seven physically active male student volunteers who performed the different protocols, isometric contraction and the combination of three velocities (V1 = 015 m s−1, V2 = 0.30 m s−1, V3 = 0.45 m s−1) and two range of movement (R1 = 25% cm ; R2 = 50% cm) protocols. Results. All protocols to evaluate trunk flexors showed an absolute reliability provided a stable repeatability for isometric and dynamic protocols with a coefficient of variation (CV) being below 10% and a high or very high relative reliability (0.69 < intraclass correlation coefficient [ICC] > 0.86). The more reliable strength manifestation (CV = 6.82%) to evaluate the concentric contraction of trunk flexors was mean force, with 0.15 m s−1 and short range of movement (V1R1) condition. The most reliable strength manifestation to evaluate the eccentric contraction of trunk flexors was peak force, with 0.15 m s−1 and a large range of movement (V1R2; CV = 5.07%), and the most reliable way to evaluate isometric trunk flexors was by peak force (CV = 7.72%). The mean force of eccentric trunk flexor strength with 0.45 m s−1 and short range of movement (V3R1) condition (r = 0.73) was best related to the maximum isometric contraction. Conclusion. Functional electromechanical dynamometry is a reliable evaluation system for assessment of trunk flexor strength.

Throwing velocity is one of the most important factors for scoring goals in handball. This study aimed to identify the type of throw and procedure for selecting the final test outcome that provide throwing velocity with the greatest reliability. Fifteen experienced handball players and 33 non-experienced participants were tested in two sessions. Each session consisted of 4 trials of 3 different throwing tests (unspecific, 7-meters, and 3-steps). The maximum value of 4 trials, average value of 4 trials, and average value of the 3 best trials were considered. Throwing velocity was highly reliable (coefficient of variation [CV]≤3.3%, intraclass correlation coefficient≥0.89) with the exception of the unspecific throw for the non-experienced group (CV≥5.9%, intraclass correlation coefficient≤0.56). The 3-steps throw (CV=1.7%) was more reliable than the 7-meters throw (CV=2.1%) (CVratio=1.19) and unspecific throw (CV = 3.8%) (CVratio=2.18), the 3 procedures provided a comparable reliability (CV range=2.4−2.6%; CVratio≤1.07), and the experienced group (CV=1.0%) presented a higher reliability than the non-experienced group (CV=4.0%) (CVratio=3.83). These results support the 3-steps throw to maximise the reliability of throwing velocity performance.

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.