Enrique Martínez-Ruiz’s research while affiliated with Oceanographic Center of Murcia and other places

Aim To evaluate the reliability of isometric peak force (IPF) in a novel “long-length” 90°Hip:20°Knee (90:20) strength test and to compare the simulated soccer match induced fatigue-recovery profile of IPF in this test with that of an isometric 90°Hip:90°Knee (90:90) position test. Methods Twenty semi-professional soccer players volunteered for the study of which 14 participated in the first part of the study which assessed 90:20 reliability (age = 21.3 ± 2.5 years, height = 1.79 ± 0.07 m, body mass = 73.2 ± 8.8 kg), while 17 completed the second part of the study evaluating fatigue-recovery (age 21.2±2.4 yrs., height = 180 ± 0.09 m, body mass 73.8 ± 8.9 kg). We evaluated the inter-session reliability of IPF in two 90:20 test protocols (hands on the wall (HW); and hands on chest (HC)) both performed on two occasions, 7 days apart. We then assessed 90:20 (HC) and 90:90 IPF immediately before (PRE) and after (POST) after a simulated soccer match protocol (BEAST90mod) and 48 (+48 h) and 72 hours (+72 h) later. Results Part one: the 90:20 showed moderate to high overall reliability (CV’s of 7.3% to 11.0%) across test positions and limbs. CV’s were lower in the HW than HC in the dominant (7.3% vs 11.0%) but the opposite happened in the non-dominant limb where CV’s were higher in the HW than HC (9.7% vs 7.3%). Based on these results, the HC position was used in part two of the study. Part two: 90:20 and 90:90 IPF was significantly lower POST compared to PRE BEAST90mod across all testing positions (p<0.001). IPF was significantly lower at +48 h compared to PRE in the 90:20 in both limbs (Dominant: p<0.01,Non-dominant: p≤0.05), but not in the 90:90. At +72 h, IPF was not significantly different from PRE in either test. Conclusions Simple to implement posterior IPF tests can help to define recovery from competition and training load in football and, potentially, in other multiple sprint athletes. Testing posterior chain IPF in a more knee extended 90:20 position may provide greater sensitivity to fatigue at 48 h post simulated competition than testing in the 90:90 position, but also may require greater degree of familiarization due to more functional testing position.

Fatigue-recovery profile raw data: Individual values for each participant on the different time points using the 90:20 and 90:90 protocols. (XLSX)

Reliability study raw data: Coefficient of variation calculations for the 90:20 protocol. (XLSX)

Introduction: Given the prevalence of hamstring injuries in football, a rehabilitation program that effectively promotes muscle tissue repair and functional recovery is paramount to minimize reinjury risk and optimize player performance and availability. Purpose: This study aimed to assess the concurrent effectiveness of administering an individualized and multifactorial criteria-based algorithm (rehabilitation algorithm [RA]) on hamstring injury rehabilitation in comparison with using a general rehabilitation protocol (RP). Methods: Implementing a double-blind randomized controlled trial approach, two equal groups of 24 football players (48 total) completed either an RA group or a validated RP group 5 d after an acute hamstring injury. Results: Within 6 months after return to sport, six hamstring reinjuries occurred in RP versus one injury in RA (relative risk = 6, 90% confidence interval = 1-35; clinical inference: very likely beneficial effect). The average duration of return to sport was possibly quicker (effect size = 0.34 ± 0.42) in RP (23.2 ± 11.7 d) compared with RA (25.5 ± 7.8 d) (-13.8%, 90% confidence interval = -34.0% to 3.4%; clinical inference: possibly small effect). At the time to return to sport, RA players showed substantially better 10-m time, maximal sprinting speed, and greater mechanical variables related to speed (i.e., maximum theoretical speed and maximal horizontal power) than the RP. Conclusions: Although return to sport was slower, male football players who underwent an individualized, multifactorial, criteria-based algorithm with a performance- and primary risk factor-oriented training program from the early stages of the process markedly decreased the risk of reinjury compared with a general protocol where long-length strength training exercises were prioritized.

Background Lower limb posterior chain isometric peak force (IPF) measured in the supine position was found to be sensitive to match induced fatigue in footballers (McCall et al. 2015). However, hamstrings fatigue following simulated football may be greatest close to full knee extension (Cohen et al. 2014), and the majority of hamstring strains occur in an extended position (Mendiguchia et al. 2012). Objective To evaluate the effects of a simulated match on IPF in a novel test and a supine position test immediately post, and at +48 h, and +72 h post-match. Design A within-subject, repeated-measures design was used to investigate the short-term effects of fatigue following a simulated football match-protocol –the BEASTmod90⁴ (Akubat et al. 2014). Participants 17 semi-professional players (age 21.2±2.4 yrs, body mass 73.8±8.9 kg) competing in a Spanish Third-Division team volunteered to participate in the study, which was implemented after the end of their competitive season. Interventions IPF was measured using a portable force platform immediately before (PRE) and after (POST) the BEASTmod90 protocol, and at +48 h and +72 h post match. Two tests were used: (i) Standing with tested leg at 90° hip and 20° knee flexion (90:20); (ii) Supine with tested leg at 90° knee and hip flexion (S90). Main Outcome Measurements Fatigue after a simulated football match-protocol. We hypothesized that the 90:20 would show greater levels of fatigue than the S90. Results IPF significantly declined PRE versus POST match in the 90:20 in both legs (p<0.001), and in the S90 in the non-dominant (p<0.001) and dominant leg (p<0.01). IPF was significantly lower at +48 h compared to PRE in the 90:20 in both legs (p<0.01, p≤0.05), but not in the S90. At +72 h, IPF was not significantly different from PRE in either test. Conclusions These findings suggest potential angle-specific differences in posterior chain fatigue following a simulated match, and that the 90:20 may be more sensitive to post competition residual posterior chain fatigue.

In the last decade, it has been suggested that whole- body vibration training (WBV) may increase neuromuscular performance and consequently affect the muscular improvement as either acute response to vibration or chronic adaptation training. Vibrating platforms generate frequencies from 5-45 Hz and vertical oscillations of 1-11 mm peak to peak, affecting more or less intensity acceleration changing by combining frequency and amplitude. Vibration training, in a session as various offers different results in regard to changes in body composition and in increasing the vertical jump, sprint, and the different manifestations of force development. These promising results await further research to establish parameters (duration, frequency and amplitude) with vibration stimulation in young active subjects. This literature review provides an update on the scientific evidence on the body vibrations in order to answer the question whether WBV, meaning the exercise by increasing the gravitational load collection, is a treatment option if the aim is to improve neuromuscular function, flexibility, balance, agility, coordination and body composition. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

A few number of researchs have analysed sagittal spine curvatures in different positions in dancers in order to show if dance practice influences sagittal spine disposition. Thus, the aim of the present research study was to compare and categorize sagittal spine curvatures in different positions in dancers. Seventy-six dancers, who studied 4th or 5th year of the Dance Conservatory Professional of Murcia, participated in this study. Thoracic and lumbar sagittal spine curvatures were measured with a Spinal Mouse® in standing, sitting and toe-touch test (TT test). After that, thoracic and lumbar curvatures were classified for each position based on normality values. Thoracic and lumbar mean vales were 18.51 ±10.71° and 24.74+8.53° in standing, 6.32±9.90° and 1.64±10.11° in sitting, and 42.61±11.14 and 34.52±9.82° in TT test, respectively. In standing position, the percentage of dancers with normal or corrected thoracic kyphosis was very similar (51.32 and 48.68%, respectively). All dancers showed a low thoracic kyphosis in sitting; while most of them had a slight thoracic kyphosis curvature in TT test (81.58%), although few participants showed a mild (13.16%) or high (5.26%) thoracic kyphosis curvature. Regarding lumbar curvature, the majority of those who participated in the study showed a slight lumbar lordosis in standing and sitting positions (75 and 92%, respectively), while few dancers had a rectification and hyperlordosis lumbar curvature in standing (23.68 and 1.31 %, respectively) and mild lumbar kyphosis in sitting (7.89%). In the TT test, most of the participant had a mild or high lumbar kyphosis curvature (77.63 and 15.79%, respectively), with a low percentage of dancers with slight curvatures (6.58%). In conclusion, systematic dance practice is associated with slight sagittal spine curvatures in standing and sitting position. However, dancers had lumbar kyphotic attitudes in maximal trunk flexion with extended knees position.

The objective of this study was to examine the effects of a neuromuscular training program combining eccentric hamstring muscle strength, plyometrics, and free/resisted sprinting exercises on knee extensor/flexor muscle strength, sprinting performance, and horizontal mechanical properties of sprint running in football (soccer) players. Sixty footballers were randomly assigned to an experimental group (EG) or a control group (CG). Twenty-seven players completed the EG and 24 players the CG. Both groups performed regular football training while the EG performed also a neuromuscular training during a 7-week period. The EG showed a small increases in concentric quadriceps strength (ES = 0.38/0.58), a moderate to large increase in concentric (ES = 0.70/0.74) and eccentric (ES = 0.66/0.87) hamstring strength, and a small improvement in 5-m sprint performance (ES = 0.32). By contrast, the CG presented lower magnitude changes in quadriceps (ES = 0.04/0.29) and hamstring (ES = 0.27/0.34) concentric muscle strength and no changes in hamstring eccentric muscle strength (ES = −0.02/0.11). Thus, in contrast to the CG (ES = −0.27/0.14), the EG showed an almost certain increase in the hamstring/quadriceps strength functional ratio (ES = 0.32/0.75). Moreover, the CG showed small magnitude impairments in sprinting performance (ES = −0.35/−0.11). Horizontal mechanical properties of sprint running remained typically unchanged in both groups. These results indicate that a neuromuscular training program can induce positive hamstring strength and maintain sprinting performance, which might help in preventing hamstring strains in football players.