Ignacio J. Chirosa

Effects of Variable Resistance Training on Maximal Strength: A Meta-Analysis

Abstract Soria-Gila, MA, Chirosa, IJ, Bautista, IJ, Baena, S, and Chirosa, LJ. Effects of variable resistance training on maximal strength: A meta-analysis. J Strength Cond Res 29(11): 3260–3270, 2015—Variable resistance training (VRT) methods improve the rate of force development, coordination between antagonist and synergist muscles, the recruitment of motor units, and reduce the drop in force produced in the sticking region. However, the beneficial effects of long-term VRT on maximal strength both in athletes and untrained individuals have been much disputed. The purpose of this study was to compare in a meta-analysis the effects of a long-term (≥7 weeks) VRT program using chains or elastic bands and a similar constant resistance program in both trained adults practicing different sports and untrained individuals. Intervention effect sizes were compared among investigations meeting our selection and inclusion criteria using a random-effects model. The published studies considered were those addressing VRT effects on the 1 repetition maximum. Seven studies involving 235 subjects fulfilled the selection and inclusion criteria. Variable resistance training led to a significantly greater mean strength gain (weighted mean difference: 5.03 kg; 95% confidence interval: 2.26–7.80 kg; Z = 3.55; p < 0.001) than the gain recorded in response to conventional weight training. Long-term VRT training using chains or elastic bands attached to the barbell emerged as an effective evidence-based method of improving maximal strength both in athletes with different sports backgrounds and untrained subjects.

Changes in the redox status and inflammatory response in handball players during one-year of competition and training

Abstract The present research was designed to evaluate the adaptive responses to oxidative stress and inflammation in handball players subjected to well-controlled training intervals over one-year of competition. Seven blood samples were collected over the season of the study, approximately one a month. Plasma lipid peroxidation, nitrite, cytokines (IL-1β, IL-6, INFγ and TNFα), and the glutathione cycle in erythrocytes, were measured. Exercise intensity, measured with the Borgs scale, increased significantly up to the middle of the competition season, coinciding with maximal creatine kinase and lactate dehydrogenase values, and then decreased at the end of the study. The inflammatory markers including nitrite, IL-1β, IL-6, and, to a lesser extent INFγ, increased early in the training season, and remained elevated until the end of the study. TNFα, however, remained low during the season. The oxidative stress response included a transient increase of the glutathione disulphide/glutathione ratio and glutathione reductase activity at the beginning of the study, returning to basal values somewhat later. Glutathione peroxidase also increased at the end of the training season, and lipid peroxidation levels remained low during the athletic season. These results suggest that well-trained athletes were best adapted to the oxidative response, although the beneficial effects of some of the inflammatory cytokines on skeletal muscle myogenesis and repair cannot be ruled out.

Short‐term ubiquinol supplementation reduces oxidative stress associated with strenuous exercise in healthy adults: A randomized trial

Studies about Coenzyme Q10 (CoQ10 ) supplementation on strenuous exercise are scarce, especially those related with oxidative stress associated with physical activity and virtually nonexistent with the reduced form, Ubiquinol. The objective of this study was to determine, for the first time, whether a short-term supplementation with Ubiquinol can prevent oxidative stress associated to strenuous exercise. The participants (n = 100 healthy and well trained, but not on an elite level) were classified in two groups: Ubiquinol (experimental group), and placebo group (control). The protocol consisted of conducting two identical strenuous exercise tests with a rest period between tests of 24 h. Blood and urine samples were collected from the participants before supplementation (basal value) (T1), after supplementation (2 weeks) (T2), after first physical exercise test (T3), after 24 h of rest (T4), and after second physical exercise test (T5).The increase observed in the lactate, isoprostanes, DNA damage, and hydroperoxide levels reveals the severity of the oxidative damage induced by the exercise. There was a reduction in the isoprostanes, 8-OHdG, oxidized LDL, and hydroperoxydes in the supplemented Ubiquinol group, an increase in total antioxidant status, fat soluble antioxidant (both plasma and membrane), and CAT activity. Also, NO in the Ubiquinol-supplemented group was maintained within a narrow range. Oxidative stress induced by strenuous exercise is accumulative and increases transiently in subsequent sessions of physical activity. A short-term supplementation (2 weeks) with Ubiquinol (200 mg/day) before strenuous exercise, decreases oxidative stress and increases plasma NO, fact that could improve endothelial function, energetic substrate supply, and muscle recovery after strenuous exercise.

Predicting Power Output of Upper Body using the OMNI-RES Scale

Abstract The main aim of this study was to determine the optimal training zone for maximum power output. This was to be achieved through estimating mean bar velocity of the concentric phase of a bench press using a prediction equation. The values for the prediction equation would be obtained using OMNI-RES scale values of different loads of the bench press exercise. Sixty males ( voluntarily participated in the study and were tested using an incremental protocol on a Smith machine to determine one repetition maximum (1RM) in the bench press exercise. A linear regression analysis produced a strong correlation (r = -0.94) between rating of perceived exertion (RPE) and mean bar velocity (Velmean). The Pearson correlation analysis between real power output (PotReal) and estimated power (PotEst) showed a strong correlation coefficient of r = 0.77, significant at a level of p = 0.01. Therefore, the OMNI-RES scale can be used to predict Velmean in the bench press exercise to control the intensity of the exercise. The positive relationship between PotReal and PotEst allowed for the identification of a maximum power-training zone.

A new physical performance classification system for elite handball players: cluster analysis.

Abstract The aim of the present study was to identify different cluster groups of handball players according to their physical performance level assessed in a series of physical assessments, which could then be used to design a training program based on individual strengths and weaknesses, and to determine which of these variables best identified elite performance in a group of under-19 [U19] national level handball players. Players of the U19 National Handball team (n=16) performed a set of tests to determine: 10 m (ST10) and 20 m (ST20) sprint time, ball release velocity (BRv), countermovement jump (CMJ) height and squat jump (SJ) height. All players also performed an incremental-load bench press test to determine the 1 repetition maximum (1RMest), the load corresponding to maximum mean power (LoadMP), the mean propulsive phase power at LoadMP (PMPPMP) and the peak power at LoadMP (PPEAKMP). Cluster analyses of the test results generated four groupings of players. The variables best able to discriminate physical performance were BRv, ST20, 1RMest, PPEAKMP and PMPPMP. These variables could help coaches identify talent or monitor the physical performance of athletes in their team. Each cluster of players has a particular weakness related to physical performance and therefore, the cluster results can be applied to a specific training programmed based on individual needs.

Concurrent Validity of a Velocity Perception Scale to Monitor Back Squat Exercise Intensity in Young Skiers.

Abstract Bautista, IJ, Chirosa, IJ, Robinson, JE, Chirosa, LJ, and Martínez, I. Concurrent validity of a velocity perception scale to monitor back squat exercise intensity in young skiers. J Strength Cond Res 30(2): 421–429, 2016—Execution velocity is among the main variables used to quantify resistance exercise intensity. The velocity at which a given load is displaced is one of the factors, which determine the training adaptations induced in the muscles. The purpose of this study was to assess the validity of the scale of perceived velocity (SPV) applied to the back squat. The study participants were 11 international level young elite skiers (8 men and 3 women) of mean age, height, weight, and estimated 1-repetition maximum/body weight ratio (1RMest/BW) 15.4 ± 1.12 years, 166.8 ± 8.83 cm, 63.6 ± 11.56 kg, and 1.61 ± 0.40, respectively. Participants performed a 2-stage protocol. In the first stage (familiarization), subjects were instructed on how to use the scale and performed an incremental load test to determine their 1RMest. In the second, or validation stage (72 hours later), exercises were executed at 6 relative intensities (20, 30, 40, 50, 60, and 70% of 1RMest) in random order in 2 sessions separated by 72 hours. Real velocity (Velreal) and perceived velocity (Velscale) values were linearly distributed showing excellent coefficients of determination (R2 = 0.98 and R2 = 0.99 for the 2-session trial). A 2-way repeated measures analysis of variance (scale [2] × session [2] × intensity [6]) revealed significant differences in the factor intensity and the interaction scale × intensity (no significant differences were detected in scale, session, scale × session, or scale × session × intensity). These data support the validity of SPV to monitor exercise intensity during lower-body strength training.