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Dr. Ulloa-Diaz, David
Nombre de publicaciĆ³n
Dr. Ulloa-Diaz, David
Nombre completo
Ulloa Diaz, David Leonardo
Facultad
Email
dulloa@ucsc.cl
ORCID
2 results
Research Outputs
Now showing 1 - 2 of 2
- PublicationReliability of isometric and isokinetic trunk flexor strength using a functional electromechanical dynamometer(PeerJ, 2019)
;Rodriguez-Perea, Angela ;Chirosa RĆos, Luis J. ;Martinez-Garcia, Dario; ;Guede Rojas, Francisco ;Jerez-Mayorga, DanielChirosa Rios, Ignacio J.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 sā1, V2 = 0.30 m sā1, V3 = 0.45 m sā1) 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 sā1 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 sā1 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 sā1 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. - PublicationAssessment of the load-velocity profile in the free-weight prone bench pull exercise through different velocity variables and regression models(PLOS, 2019)
;GarcĆa-Ramos, Amador; ;Barboza GonzĆ”lez, Paola ;RodrĆguez Perea, Ćngela ;MartĆnez GarcĆa, DarĆo ;Quidel CatrilelbĆŗn, Mauricio ;Guede Rojas, Francisco; ;Janicijevic, DanicaWeakley, JonathonThis aims of this study were (I) to determine the velocity variable and regression model which best fit the load-velocity relationship during the free-weight prone bench pull exercise, (II) to compare the reliability of the velocity attained at each percentage of the one-repetition maximum (1RM) between different velocity variables and regression models, and (III) to compare the within- and between-subject variability of the velocity attained at each %1RM. Eighteen men (14 rowers and four weightlifters) performed an incremental test during the free-weight prone bench pull exercise in two different sessions. General and individual load-velocity relationships were modelled through three velocity variables (mean velocity [MV], mean propulsive velocity [MPV] and peak velocity [PV]) and two regression models (linear and second-order polynomial). The main findings revealed that (I) the general (Pearsonās correlation coefficient [r] range = 0.964ā0.973) and individual (median r = 0.986 for MV, 0.989 for MPV, and 0.984 for PV) load-velocity relationships were highly linear, (II) the reliability of the velocity attained at each %1RM did not meaningfully differ between the velocity variables (coefficient of variation [CV] range = 2.55ā7.61% for MV, 2.84ā7.72% for MPV and 3.50ā6.03% for PV) neither between the regression models (CV range = 2.55ā7.72% and 2.73ā5.25% for the linear and polynomial regressions, respectively), and (III) the within-subject variability of the velocity attained at each %1RM was lower than the between-subject variability for the light-moderate loads. No meaningful differences between the within- and between-subject CVs were observed for the MV of the 1RM trial (6.02% vs. 6.60%; CV ratio = 1.10), while the within-subject CV was lower for PV (6.36% vs. 7.56%; CV ratio = 1.19). These results suggest that the individual load-MV relationship should be determined with a linear regression model to obtain the most accurate prescription of the relative load during the free-weight prone bench pull exercise.