Open Access
Optimal reactive strength index: is it an accurate variable to optimize plyometric training effects on measures of physical fitness in young soccer players?
(Wolters Kluwer, 2018) Ramírez Campillo, Rodrigo; Álvarez, Cristian; García Pinillos, Felipe; Sánchez Sánchez, Javier; Izquierdo Redín, Mikel; Ciencias de la Salud; Osasun Zientziak
This study aimed to compare the effects of drop-jump training using a fixed drop-box height (i.e., 30-cm [FIXED]) vs. an optimal (OPT) drop-box height (i.e., 10-cm to 40-cm: generating an OPT reactive strength index [RSI]) in youth soccer players' physical fitness. Athletes were randomly allocated to a control group (n = 24; age = 13.7 years), a fixed drop-box height group (FIXED, n = 25; age = 13.9 years), or an OPT drop-box height group (OPT, n = 24; age = 13.1 years). Before and after 7 weeks of training, tests for the assessment of jumping (countermovement jump [CMJ], 5 multiple bounds), speed (20-m sprint time), change of direction ability (CODA [Illinois test]), strength {RSI and 5 maximal squat repetition test (5 repetition maximum [RM])}, endurance (2.4-km time trial), and kicking ability (maximal kicking distance) were undertaken. Analyses revealed main effects of time for all dependent variables (p < 0.001, d = 0.24–0.72), except for 20-m sprint time. Analyses also revealed group × time interactions for CMJ (p < 0.001, d = 0.51), depth jump (DJ) (p < 0.001, d = 0.30), 20-m sprint time (p < 0.001, d = 0.25), CODA (p < 0.001, d = 0.22), and 5RM (p < 0.01, d = 0.16). Post hoc analyses revealed increases for the FIXED group (CMJ: 7.4%, d = 0.36; DJ: 19.2%, d = 0.49; CODA: −3.1%, d = −0.21; 5RM: 10.5%, d = 0.32) and the OPT group (CMJ: 16.7%, d = 0.76; DJ: 36.1%, d = 0.79; CODA: −4.4%, d = −0.34; 5RM: 18.1%, d = 0.47). Post hoc analyses also revealed increases for the OPT group in 20-m sprint time (−3.7%, d = 0.27). Therefore, to maximize the effects of plyometric training, an OPT approach is recommended. However, using adequate fixed drop-box heights may provide a rational and practical alternative.
Open Access
Aerobic capacity and future cardiovascular risk in Indian community from a low-income area in Cauca, Colombia
(BioMed Central, 2017) Ramírez Vélez, Robinson; Correa Bautista, Jorge Enrique; Ramos Sepúlveda, Jeison Alexander; Piñeros Álvarez, Carlos Andrés; Giraldo, Lorena Isabel; Izquierdo Redín, Mikel; García Hermoso, Antonio; Rodríguez Rodríguez, Fernando; Cristi Montero, Carlos; Ciencias de la Salud; Osasun Zientziak
Background: Several studies indicates that children’s aerobic capacity levels are predictors of the future risk of non-communicable diseases. Therefore, the aim of this study was to establish the proportion of subjects whose aerobic capacity is indicative of future cardiovascular risk in Indian-Nasa community from a low-income area in Cauca, Colombia. Methods: We performed a cross-sectional analysis of morphological component (height, weight, body mass index (BMI), waist circumference, triceps skinfold, subscapular skinfold, and body fat percent [BF%]), and the cardiorespiratory component (course-navette 20 m, shuttle run test and estimation of maximal oxygen consumption by indirect VO2max) from 576 participants (319 boys and 257 girls) aged 10 to 17.9 years, using the standardized FUPRECOL test battery. Results: We showed that the boys performed better than the girls in cardiorespiratory fitness. The proportion of subjects with an aerobic capacity indicative of future cardiovascular risk was 7.3%. By sex, 3.8% of boys and 11.7% of girls (X2 p = 0.001) displayed an unhealthy aerobic capacity in this study. Conclusion: The findings of this study that provide the first data on aerobic capacity health for Colombian Nasa Indian children and adolescents aged 10–17.9 years. Although the known loss of aerobic capacity is a serious consequence of the future risk of non-communicable diseases, the deterioration of physical fitness deserves increased attention among indigenous population.
Open Access
High muscular fitness has a powerful protective cardiometabolic effect in adults: influence of weight status
(BioMed Central, 2016) Ramírez Vélez, Robinson; Correa Bautista, Jorge Enrique; Lobelo, Felipe; Izquierdo Redín, Mikel; Alonso Martínez, Alicia; Rodríguez Rodríguez, Fernando; Cristi Montero, Carlos; Ciencias de la Salud; Osasun Zientziak
Background: Low levels of muscular fitness (MF) are recognized as an important marker of nutritional status and a predictor of metabolic complications, cardiovascular disease and death, however, the relationship between MF, body mass index (BMI) and the subsequent cardiometabolic protective effects has been less studied among Latin American populations. This study identified an association between MF and the cardiometabolic risk score index (CMRSI) and the lipid-metabolic cardiovascular risk index (LMCRI) in a wide sample of university students grouped according to their BMI. Methods: Six thousand ninety five healthy males (29.6 ± 11.7 year-old) participated in the study. Absolute strength was measured using a T.K.K. analogue dynamometer (handgrip), and the participant’s strength was then calculated relative to their body mass (MF/BM). The LMCRI was derived from the levels of triglycerides, low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), and glucose levels in a blood sample. The CMRSI was calculated by summing the standardized residuals (z-score) for waist circumference, total cholesterol, LDL-c, triglycerides, HDL-c, and median blood pressure. Subjects were divided into six subgroups according to BMI (normal vs. overweight/obese) and MF/BM tertiles (unfit, average, fit). Results: The group of participants with low and moderate levels of MF/BM showed higher CMRSI values independent of BMI (P < 0.001). The group with normal BMI and high MF/BM had the highest levels of cardiometabolic protection. All overweight/obese BMI groups had significantly higher LMCRI values independent of the level of MF/BM (P < 0.001). Conclusions: Participants with high MF/BM showed reduced cardiometabolic risk, which increased significantly when they were within normal parameters.
Open Access
Handgrip strength attenuates the adverse effects of overweight on cardiometabolic risk factors among collegiate students but not in individuals with higher fat levels
(Nature Research, 2019) García Hermoso, Antonio; Tordecilla Sanders, Alejandra; Correa Bautista, Jorge Enrique; Peterson, Mark Dean; Izquierdo Redín, Mikel; Prieto Benavides, Daniel Humberto; Sandoval Cuellar, Carolina; González Ruiz, Katherine; Ramírez Vélez, Robinson; Ciencias de la Salud; Osasun Zientziak
The aims of this study are to (i) examine a clustered metabolic syndrome composite score (MetScore) and fatness among college students across body mass index (BMI) categories, and (ii) determine whether fit individuals have lower MetScores, fewer individual metabolic syndrome components, and lower fatness than unfit individuals across BMI categories. A total of 1,795 participants aged >18 years who participated in The FUPRECOL Study were selected for the present analyses. Handgrip strength was tested by a grip dynamometer and used to classify adults as fit or unfit. Among all participants, MetScore, percentage of body fat, and visceral adiposity increased linearly across the BMI categories among college students (all P < 0.001). Individuals who were overweight and fit had a lower MetScore (-0.6 SD; P =0.02), body fat percentage (-2.6%; P < 0.001) and visceral adiposity (-0.2; P = 0.01) than unfit peers. Moderately fit obese individuals had significantly lower visceral fat levels than unfit obese peers (-3.0; P = 0.03). These results suggest that having adequate handgrip strength-a proxy of overall strength capacity-may attenuate obesity-related cardiometabolic risk. Moreover, weight loss should be recommended to all individuals with obesity, even among those who are currently considered fit.
Open Access
Schoolbag weight carriage in Portuguese children and adolescents: a cross-sectional study comparing possible influencing factors
(BMC, 2019) Barbosa, João; Marqués, Mário C.; Izquierdo Redín, Mikel; Neiva, Henrique P.; Barbosa, Tiago M.; Ramírez Vélez, Robinson; Alonso Martínez, Alicia; García Hermoso, Antonio; Aguado Jiménez, Roberto; Marinho, Daniel; Ciencias de la Salud; Osasun Zientziak
Background Schoolbags and the consequences of carrying them, particularly those associated with overload, are often studied as a health concern. Modifications in gait and posture were reported when children carried loads that corresponded to more than 10% of their body weight (BW). The aims of this study were to verify the load that is carried by Portuguese students and how it is influenced by factors such as school grade, school schedule, lunch site, physical education, sex and body mass index (BMI). Acquiring a more specific knowledge of the Portuguese context and understanding the influence of these factors may allow us to generate proposals to control them in ways that benefit students.MethodsThe load carried by students in the 5th grade (10.60.4years) and 9th grade (14.70.6years) were weighed with a luggage scale on all days of the week, resulting in 680 evaluations. Data related to the school day were also collected, such as the student's lunch site, how he or she got to school and his or her school schedule for that day. Individual height and weight were also assessed. Results The 5th grade students carried greater loads than the 9th grade students, resulting in a substantial difference relative to their BW. The school loads of the 5th grade students were mostly greater than 10% of their BWs. Girls tended to carry heavier loads than boys, and overweight students also tended to carry heavier loads. Students who could eat lunch at home carried less weight, and on physical education days, the total load carried increased, but the backpacks of the 5th grade students were lighter.Conclusions The results of the current study describe excessive schoolbag weight among Portuguese students and expound on some of the factors that influence it, which can help researchers and professionals design a solution to decrease children's schoolbag loads.
Open Access
A protocol for a new methodological model for work-related shoulder complex injuries: from diagnosis to rehabilitation
(BioMed Central, 2017) Setuain Chourraut, Igor; González Izal, Miriam; Paularena, Ainara; Luque, José Luis; Andersen, Lars L.; Izquierdo Redín, Mikel; Ciencias de la Salud; Osasun Zientziak
Background: Work-related injuries of the shoulder complex represent a challenge for clinicians because of the large variety of clinical entities involved and the broad anatomic structures that can be affected. Furthermore, commonly performed orthopedic tests have demonstrated limited accuracy for diagnosing the injury despite considerable research efforts. The aim of this study protocol is therefore to describe a comprehensive approach integrating both a clinical- and functional status-based pathology and an adapted rehabilitation prescription. Methods/Design: A longitudinal cohort study will be performed at the Department of Rehabilitation and Medical Assistance of a mutual insurance society for work-related injury management in Spain (Mutua Navarra, Pamplona, Navarra Spain). Patients will be attended by an occupational physician who specializes in work-related injuries and is part of the project team that will systematically visit all the participants. After the medical diagnosis and any requested supplementary evaluations (i.e., radiological examinations), the patients will be referred to the rehabilitation service. Before the physiotherapeutic rehabilitation program is initiated, the patients will undergo a comprehensive functional screening at the biomechanics laboratory. Using a decision-making scheme, the identified functional deficits will be used to customize the individual rehabilitation plan. Discussion: The proposed objective criteria-based shoulder diagnosis and rehabilitation model could be a new effective strategy for minimizing the time required to regain functional capacity and recover from symptoms among patients with work-related shoulder injuries.
Open Access
Energy metabolism during repeated sets of leg press exercise leading to failure or not
(Public Library of Science, 2012) Gorostiaga Ayestarán, Esteban; Navarro Amezqueta, Ion; Calbet, José A. L.; Hellsten, Ylva; Cusso, Roser; Guerrero, Mario; Granados, Cristina; González Izal, Miriam; Ibáñez Santos, Javier; Izquierdo Redín, Mikel; Ciencias de la Salud; Osasun Zientziak
This investigation examined the influence of the number of repetitions per set on power output and muscle metabolism during leg press exercise. Six trained men (age 3466 yr) randomly performed either 5 sets of 10 repetitions (10REP), or 10 sets of 5 repetitions (5REP) of bilateral leg press exercise, with the same initial load and rest intervals between sets. Muscle biopsies (vastus lateralis) were taken before the first set, and after the first and the final sets. Compared with 5REP, 10REP resulted in a markedly greater decrease (P,0.05) of the power output, muscle PCr and ATP content, and markedly higher (P,0.05) levels of muscle lactate and IMP. Significant correlations (P,0.01) were observed between changes in muscle PCr and muscle lactate (R2 = 0.46), between changes in muscle PCr and IMP (R2 = 0.44) as well as between changes in power output and changes in muscle ATP (R2 = 0.59) and lactate (R2 = 0.64) levels. Reducing the number of repetitions per set by 50% causes a lower disruption to the energy balance in the muscle. The correlations suggest that the changes in PCr and muscle lactate mainly occur simultaneously during exercise, whereas IMP only accumulates when PCr levels are low. The decrease in ATP stores may contribute to fatigue.
Open Access
Physical fitness profile of competitive young soccer players: determination of positional differences
(SAGE, 2016) Marqués, Mário C.; Izquierdo Redín, Mikel; Gabbett, Tim J.; Travassos, Bruno; Branquinho, Luís; Ciencias de la Salud; Osasun Zientziak
The aim of this study was to compare the anthropometric and physical fitness characteristics of the different playing positions in adolescent soccer players. Furthermore, differences among playing ages (under 14, under 16, and under 18 years) were determined. One hundred and sixty-seven young male national level soccer players were tested on anthropometric characteristics and physical performance tests (30 m sprint, ball kicking, overhead medicine ball throw, and countermovement jump). The results demonstrated differences in anthropometric characteristics between positions (p < 0.05). Differences were also found in the physical performance tests; forwards performed better in the throwing, countermovement jump, and sprint tests than defenders. Midfielders demonstrated greater countermovement jump performances than right defenders. Our results highlight that there is an influence of playing position on the anthropometric and physical qualities in adolescent players. This emphasizes the importance of evaluating the physical profile of players and their development according to playing age and playing position.
Open Access
Effects of plyometric training and beta-alanine supplementation on maximal-intensity exercise and endurance in female soccer players
(De Gruyter, 2017) Rosas, Fabián; Ramírez Campillo, Rodrigo; Martínez Salazar, Cristian; Caniuqueo Vargas, Alexis; Cañas Jamet, Rodrigo; McCrudden, Emma; Meylan, César; Moran, Jason; Nakamura, Fábio Y.; Pereira, Lucas A.; Loturco, Irineu; Díaz, Daniela; Izquierdo Redín, Mikel; Ciencias de la Salud; Osasun Zientziak
Plyometric training and beta-alanine supplementation are common among soccer players, although its combined use had never been tested. Therefore, a randomized, double-blind, placebo-controlled trial was conducted to compare the effects of a plyometric training program, with or without beta-alanine supplementation, on maximalintensity and endurance performance in female soccer players during an in-season training period. Athletes (23.7 ± 2.4 years) were assigned to either a plyometric training group receiving a placebo (PLACEBO, n = 8), a plyometric training group receiving beta-alanine supplementation (BA, n = 8), or a control group receiving placebo without following a plyometric training program (CONTROL, n = 9). Athletes were evaluated for single and repeated jumps and sprints, endurance, and change-of-direction speed performance before and after the intervention. Both plyometric training groups improved in explosive jumping (ES = 0.27 to 1.0), sprinting (ES = 0.31 to 0.78), repeated sprinting (ES = 0.39 to 0.91), 60 s repeated jumping (ES = 0.32 to 0.45), endurance (ES = 0.35 to 0.37), and change-of-direction speed performance (ES = 0.36 to 0.58), whereas no significant changes were observed for the CONTROL group. Nevertheless, compared to the CONTROL group, only the BA group showed greater improvements in endurance, repeated sprinting and repeated jumping performances. It was concluded that beta-alanine supplementation during plyometric training may add further adaptive changes related to endurance, repeated sprinting and jumping ability.
Open Access
The insulin-like growth factor system is modulated by exercise in breast cancer survivors: a systematic review and meta-analysis
(BioMed Central, 2016) Meneses Echávez, José Francisco; González Jiménez, Emilio; Schmidt Río-Valle, Jacqueline; Correa Bautista, Jorge Enrique; Izquierdo Redín, Mikel; Ramírez Vélez, Robinson; Ciencias de la Salud; Osasun Zientziak
Background: Insulin-like growth factors (IGF´s) play a crucial role in controlling cancer cell proliferation, differentiation and apoptosis. Exercise has been postulated as an effective intervention in improving cancerrelated outcomes and survival, although its effects on IGF´s are not well understood. This meta-analysis aimed to determine the effects of exercise in modulating IGF´s system in breast cancer survivors. Methods: Databases of PuMed, EMBASE, Cochrane Central Register of Controlled Trials, EMBASE, ClinicalTrials. gov, SPORTDiscus, LILACS and Scopus were systematically searched up to November 2014. Effect estimates were calculated through a random-effects model of meta-analysis according to the DerSimonian and Laird method. Heterogeneity was evaluated with the I2 test. Risk of bias and methodological quality were evaluated using the PEDro score. Results: Five randomized controlled trials (n = 235) were included. Most women were post-menopausal. Highquality and low risk of bias were found (mean PEDro score = 6.2 ± 1). Exercise resulted in significant improvements on IGF-I, IGF-II, IGFBP-I, IGFBP-3, Insulin and Insulin resistance (P < 0.05). Non-significant differences were found for Glucose. Aerobic exercise improved IGF-I, IGFBP-3 and Insulin. No evidence of publication bias was detected by Egger´s test (p = 0.12). Conclusions: Exercise improved IGF´s in breast cancer survivors. These findings provide novel insight regarding the molecular effects of exercise on tumoral microenvironment, apoptosis and survival in breast cancer survivors.