Altitude‑induced effects on neuromuscular, metabolic and perceptual responses before, during and after a high‑intensity resistance training session

Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This work was supported by the Spanish Ministry of Science, Innovation and Universities under Grant (PGC2018-097388-B-I00-MCI/AEI/FEDER, UE), by the Andalusian FEDER Operational Program (B-CTS-374-UGR20) and FPU pre-doc- toral Grant (FPU18/00686) awarded to one of the authors (CB). The authors have no relevant financial or non-financial interests to disclose.Purpose We tested if an acute ascending to 2320 m above sea level (asl) affects corticospinal excitability (CSE) and intracortical inhibition (SICI) measured with transcranial magnetic stimulation (TMS) at rest, before, during and after a traditional hypertrophy-oriented resistance training (R-T) session. We also explored whether blood lactate concentration (BLa), ratings of perceived exertion (RPE), perceived muscular pain and total training volume differed when the R-T session was performed at hypoxia (H) or normoxia (N). Methods Twelve resistance-trained men performed eight sets of 10 repetitions at 70% of one repetition maximum of a bar biceps curl at N (SpO(2) = 98.0 +/- 0.9%) and H (at 2320 asl, SpO(2) = 94.0 +/- 1.9%) in random order. Before each session, a subjective well-being questionnaire, the resting motor threshold (rMT) and a single pulse recruitment curve were measured. Before, during and after the R-T session, BLa, RPE, muscle pain, CSE and SICI were measured. Results Before the R-T session only the rMT differed between H (- 5.3%) and N (ES = 0.38). RPE, muscle pain and BLa increased through the R-T session and were greater at H than N (12%, 54% and 15%, respectively) despite a similar training volume (1618 +/- 468 kg vs. 1638 +/- 509 kg). CSE was reduced during the R-T session (similar to 27%) but recovered ten minutes after, regardless of the environmental condition. SICI did not change after any R-T session. Conclusions The data suggest that acute exposure to moderate hypoxia slightly increased the excitability of the most excitable structures of the corticospinal tract but did not influence intracortical or corticospinal responses to a single R-T session.CRUE-CSICSpanish Ministry of Science, Innovation and Universities (PGC2018-097388-B-I00-MCI/AEI/FEDER, UE)Andalusian FEDER Operational Program (B-CTS-374-UGR20)FPU pre-doctoral (FPU18/00686

Maximal isometric handgrip strength and endurance differences between elite and non-elite young judo athletes

Background and Study Aim: Judo is a combat sport in which the maintenance of handgrip strength is essential because the judokas repeat this action continuously during the struggle for grip. While descriptions of maximal isometric handgrip strength in judokas are relatively common, few data exist concerning the ability to resist successive isometric contractions in the hands and its relation to performance. The aim of this study was the differences and similarities between elite and non-elite young judokas in terms of maximal isometric handgrip strength and their endurance to this strength.Material and Methods: Seventy-three adolescents participants from three national (elite) and one regional team (non-elite) were tested. The maximal isometric handgrip strength was recorded during a maximum test of 6 s with an electronic Digimax dynamometer. The endurance to the isometric handgrip strength was measured by a test consisting of 8 contractions of 10 s each alternating with 10 s of passive rest, and was also recorded with the same machine.Results: The endurance test decreases the relative and mean isometric handgrip strength of male and female judokas (p≤0.01), irrespective of their competitive level. However, male and female elite judokas developed higher levels of relative isometric handgrip strength in the maximum test and during all contractions of the endurance test than non-elite judokas (p≤0.01 for both sexes). In all cases, the non-elite group took longer to reach the maximal isometric handgrip strength (p≤0.05).Conclusions: Maximal isometric handgrip strength and the endurance to this strength were able to distinguish between elite and non-elite young judokas. Coaches should include conditioning programs for both maximal isometric handgrip strength and the ability to resist successive isometric contractions to maximize performance

Hypoxia matters: comparison of external and internal training load markers during an 8‑week resistance training program in normoxia, normobaric hypoxia and hypobaric hypoxia

Purpose To compare external and internal training load markers during resistance training (RT) in normoxia (N), intermittent hypobaric hypoxia (HH), and intermittent normobaric hypoxia (NH). Methods Thirty-three volunteers were assigned an 8-week RT program in either N (690 m, n = 10), HH (2320 m, n = 10), or NH (inspired fraction of oxygen = 15.9%; ~ 2320 m, n = 13). The RT program (3x/week) consisted of six exercises, with three sets of six to 12 repetitions at ~ 70% of one repetition maximum (1RM) with the first session of each week sed for analysis. 1RM in back squat and bench press was used to evaluate muscle strength before and after the program. External load was assessed by the volume load relative to body mass (RVL, kg·kg−1). Internal load was assessed by the ratings of perceived exertion (RPE) and heart rate (HR). Results Smaller relative improvements were found for the back squat in the N group (11.5 ± 8.8%) when compared to the NH group (22.2 ± 8.2%, P = 0.01) and the HH group (22 ± 8.1%, P = 0.02). All groups showed similar RVL, HR responses and RPE across the program (P˃0.05). However, reduced HR recovery values, calculated as the difference between the highest HR value (HRpeak) and the resting heart rate after a two min rest, were seen in the N and NH groups across the program (P < 0.05). Conclusion It seems that 8 weeks of intermittent RT in hypoxic environments could maximize time-efficiency when aiming to improve strength levels in back squat without evoking higher levels of physiological stress. Performing RT at hypobaric hypoxia may improve the cardiorespiratory response, which in turn could speed recovery.Open access funding provided by Örebro UniversitySpanish Ministry of Science, Innovation and Universities under grant [PGC2018-097388-B-I00-MCI/AEI/FEDER, UE]Andalusian FEDER Operational Program [B-CTS-374-UGR20]FPU pre-doctoral grant [FPU18/00686

Effect of a resistance exercise at acute moderate altitude on muscle health biomarkers

The intensification of the stress response during resistance training (RT) under hypoxia conditions could trigger unwanted effects that compromise muscle health and, therefore, the ability of the muscle to adapt to longer training periods. We examined the effect of acute moderate terrestrial hypoxia on metabolic, inflammation, antioxidant capacity and muscle atrophy biomarkers after a single RT session in a young male population. Twenty healthy volunteers allocated to the normoxia (N < 700 m asl) or moderate altitude (HH = 2320 m asl) group participated in this study. Before and throughout the 30 min following the RT session (3 × 10 reps, 90 s rest, 70% 1RM), venous blood samples were taken and analysed for circulating calcium, inorganic phosphate, cytokines (IL-6, IL-10 and TNF-α), total antioxidant capacity (TAC) and myostatin. Main results displayed a marked metabolic stress response after the RT in both conditions. A large to very large proportional increase in the adjusted to pre-exercise change of inflammatory and anti-inflammatory markers favoured HH (serum TNF-α [ES = 1.10; p = 0.024] and IL-10 [ES = 1.31; p = 0.009]). The exercise produced a similar moderate increment of myostatin in both groups, followed by a moderate non-significant reduction in HH throughout the recovery (ES =  − 0.72; p = 0.21). The RT slightly increased the antioxidant response regardless of the environmental condition. These results revealed no clear impact of RT under acute hypoxia on the metabolic, TAC and muscle atrophy biomarkers. However, a coordinated pro/anti-inflammatory response balances the potentiated effect of RT on systemic inflammatioUniversidad de Granada/CBUA This research was funded by the Spanish Ministry of ScienceInnovation and Universities (grant number PGC2018-097388-B-I00-MCI/AEI/FEDER, UE)FEDER/Junta de Andalucía-Ministry of Economic TransformationIndustry, Knowledge and Universities (grant number B-CTS-374-UGR20

Predicting Vertical Jump Height from Bar Velocity

The objective of the study was to assess the use of maximum (Vmax) and final propulsive phase (FPV) bar velocity to predict jump height in the weighted jump squat. FPV was defined as the velocity reached just before bar acceleration was lower than gravity (-9.81 m·s-2). Vertical jump height was calculated from the take-off velocity (Vtake-off) provided by a force platform. Thirty swimmers belonging to the National Slovenian swimming team performed a jump squat incremental loading test, lifting 25%, 50%, 75% and 100% of body weight in a Smith machine. Jump performance was simultaneously monitored using an AMTI portable force platform and a linear velocity transducer attached to the barbell. Simple linear regression was used to estimate jump height from the Vmax and FPV recorded by the linear velocity transducer. Vmax (y = 16.577x - 16.384) was able to explain 93% of jump height variance with a standard error of the estimate of 1.47 cm. FPV (y = 12.828x - 6.504) was able to explain 91% of jump height variance with a standard error of the estimate of 1.66 cm. Despite that both variables resulted to be good predictors, heteroscedasticity in the differences between FPV and Vtake-off was observed (r2 = 0.307), while the differences between Vmax and Vtake-off were homogenously distributed (r2 = 0.071). These results suggest that Vmax is a valid tool for estimating vertical jump height in a loaded jump squat test performed in a Smith machine.This study was supported by grants awarded by the Spanish Ministry of Science and Innovation (DEP2012-35774) and Ministry of Education, Culture and Sport (Predoctoral Grant FPU12/00360)

Effect of acute exposure to moderate altitude on kinematic variables of the ipponseoi- nage and its relationship with the countermovement jump in elite judokas

This study aimed to assess the effect of acute exposure to moderate altitude on kinematic variables of the ippon-seoi-nage and on the mechanical outputs of the countermovement jump (CMJ). Thirteen elite male judokas from the Spanish Judo Training Centre in Valencia (age: 21.54 ± 2.15 years) participated in the study. All of them performed an incremental CMJ test and an ippon-seoi-nage technique test before (N) and after the ascent to a moderate altitude of 2320 m above the sea level (H). A linear velocity transducer was attached to the bar to assess the mechanical outputs of each loaded CMJ at different percentages of their own body weight (25, 50, 75 and 100%). A wearable sensor was used to assess the kinematic variables (times, accelerations and angular velocities) transferred to a dummy during the technique test. The kinematic variables showed great individual reliability (CV = 8.46% in N; CV = 8.37% in H), which contrasted with low reliability observed when the whole group was considered. The smallest important CV ratio (>1.15) showed that H caused changes in the reliability of the kinematic variables, with some variables becoming more reliable and others losing the reliability they had in N. H also caused small increments in peak velocity across all loads tested in the CMJ (+3.67%; P<0.05). In contrast, no changes in the kinematic variables were verified.This study was funded by the Spanish Ministry of Economy and Competitiveness (DEP2015-64350-P MINECO/FEDER), and by a FPI pre-doctoral grant (BES-2016- 078035) awarded to one of the authors (FA)

Influence of lower-limb muscle power-related variables on the ippon-seoi-nage of elite judokas

This study investigated the influence of the lower-limb extension mechanical variables (strength variables) on the ippon-seoi-nage kinematic variables (technical variables) in elite judokas. Additionally, we studied the effect of performing ippon-seoi-nage with lower-limb flexion-extension action vs. without it, on the technical and strength variables, as well as on their relationship. Twenty-four male elite judokas were classified in two groups depending on the type of ippon-seoi-nage performed, i.e., with lower-limb flexion-extension action or without it. Mechanical outputs from an incremental loaded countermovement jump test were assessed, as well as kinematic variables transferred to the uke (person who is thrown) during an ippon-seoi-nage technique test. The strength parameters did not positively correlate with the technical ones, showing no transference between the variables studied. Furthermore, the judokas that performed the ippon-seoi-nage with lower-limb flexion-extension action presented lower times in the execution of the technique than the group that did not perform this action. Therefore, the transference from strength parameters to the performance of ippon-seoi-nage is not yet explained, even when considering different technical styles.This work was supported by the Spanish Ministry of Economy, Industry and Competitiveness under Grant DEP2015-64350-P MINECO/FEDER and FPI pre-doctoral grant under Grant BES-2016-078035 awarded to one of the authors

Effects of Resistance Training in Hypobaric vs. Normobaric Hypoxia on Circulating Ions and Hormones

Acknowledgments: The authors thank the High performance Center of Sierra Nevada, Spain, and all the participants who volunteered for this investigation. The authors also thank Dymatize Europe and Vithas Granada for respectively supplying the meal replacement and blood collection equipment in this study.Funding: This work was supported by the Spanish Ministry of Science, Innovation and Universities under grant [PGC2018-097388-B-I00 -MCIN/AEI/FEDER, UE] and by the Andalusian FEDER Operational Program [A-SEJ-246-UGR18 and B-CTS-374-UGR20]. This study has been also supported by the Government of Extremadura (Spain) with funding from the European Regional Development Fund [Grant Ref: GR21189].Hypobaric hypoxia (HH) seems to lead to different responses compared to normobaric hypoxia (NH) during physical conditioning. The aim of the study was to analyze the hormonal and circulating ion responses after performing high-intensity resistance training with different inter-set rest under HH and NH condition. Sixteen male volunteers were randomly divided into two training groups. Each group completed two counterbalanced resistance training sessions (three sets × ten repetitions, remaining two repetitions in reserve), with both one- and two-minute inter-set rest, under HH and NH. Blood samples were obtained to determine hormones and circulating ions (Ca2+, Pi, and HCO3−) at baseline and after training sessions (5, 10, and 30 min). Resistance training with one-minute rest caused greater hormonal stress than with two-minute rest in cortisol and growth hormone, although the hypoxic environmental condition did not cause any significant alterations in these hormones. The short inter-set rest also caused greater alterations in HCO3− and Pi than the longer rest. Additionally, higher levels of Ca2+ and Pi, and lower levels of HCO3−, were observed after training in HH compared to NH. Metabolic and physiological responses after resistance training are mediated by inter-set rest intervals and hypoxic environmental condition. According to the alterations observed in the circulating ions, HH could cause greater muscular fatigue and metabolic stress than NH.Government of ExtremaduraMinisterio de Ciencia, Innovación y Universidades A-SEJ-246-UGR18, B-CTS-374-UGR20, PGC2018-097388-B-I00 -MCIN/AEI/FEDEREuropean Regional Development Fund GR2118

Hormonal and Inflammatory Responses to Hypertrophy-Oriented Resistance Training at Acute Moderate Altitude

This research was funded by the Spanish Ministry of Science, Innovation and Universities, grant number PGC2018-097388-B-I00, by the Andalusian FEDER Operational Program, grant number A-SEJ-246-UGR18 and FPU pre-doctoral, grant number FPU18/00686 awarded to one of the authors.The authors thank the High Performance Center of Sierra Nevada, Spain and all the participants who volunteered for this investigation. The authors also thank Dymatize Europe for supplying the meal replacement supplements used in this study.This study investigated the effect of a traditional hypertrophy-oriented resistance training (R-T) session at acute terrestrial hypoxia on inflammatory, hormonal, and the expression of miR-378 responses associated with muscular gains. In a counterbalanced fashion, 13 resistance trained males completed a hypertrophic R-T session at both moderate-altitude (H; 2320 m asl) and under normoxic conditions (N; <700 m asl). Venous blood samples were taken before and throughout the 30 min post-exercise period for determination of cytokines (IL6, IL10, TNF alpha), hormones (growth hormone [GH], cortisol [C], testosterone), and miR-378. Both exercise conditions stimulated GH and C release, while miR-378, testosterone, and inflammatory responses remained near basal conditions. At H, the R-T session produced a moderate to large but nonsignificant increase in the absolute peak values of the studied cytokines. miR-378 revealed a moderate association with GH (r = 0.65; p = 0.026 and r = -0.59; p = 0.051 in N and H, respectively) and C (r = 0.61; p = 0.035 and r = 0.75; p = 0.005 in N and H, respectively). The results suggest that a R-T session at H does not differentially affect the hormonal, inflammatory, and miR-378 responses compared to N. However, the standardized mean difference detected values in the cytokines suggest an intensification of the inflammatory response in H that should be further investigated.Spanish Ministry of Science, Innovation and Universities PGC2018-097388-B-I00Andalusian FEDER Operational Program A-SEJ-246-UGR18FPU pre-doctoral FPU18/0068

Influencia de la reducción del tiempo de apoyo en la eficacia de la aplicación de la fuerza explosiva, su entrenamiento : tesis doctoral /Paulino Padial Puche; director Antonio Oña Sicilia

Univ. de Granad