Neuromuscular Adaptations after an Altitude Training Camp in Elite Judo Athletes

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

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 (RT) session. We also explored whether blood lactate concentration (BLa), ratings of perceived exertion (RPE), perceived muscular pain and total training volume differed when the RT 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 (SpO2 = 98.0 ± 0.9%) and H (at 2320 asl, SpO2 = 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 RT session, BLa, RPE, muscle pain, CSE and SICI were measured.

RESULTS

Before the RT session only the rMT differed between H (- 5.3%) and N (ES = 0.38). RPE, muscle pain and BLa increased through the RT 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 RT session (~ 27%) but recovered ten minutes after, regardless of the environmental condition. SICI did not change after any RT 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 RT session.

Perceived Discomfort and Voluntary Activation of Quadriceps Muscle Assessed with Interpolated Paired or Triple Electrical Stimuli

Voluntary drive of the exercising muscle is usually assessed with the interpolated twitch technique (ITT), using paired supramaximal electrical stimuli. The aim of this study was to directly compare voluntary activation (VA) of the quadriceps muscle (QM) measured with the ITT, using paired and triple electrical stimuli during maximal voluntary isometric contraction (MVIC). In addition, perceived discomfort was compared with the use of paired and triple electrical stimuli during ITT. Ten healthy participants (23.6 ± 1.6 years) were included. They performed four MVIC, with paired or triple stimuli, in random order. MVIC torque, superimposed evoked torque, evoked torque at rest, VA, and visual analogue scale for pain (VAS-pain), were analysed. The amplitude of the triplet-evoked torque was higher than doublet-evoked torque, i.e., the signal-to-noise ratio increased. However, the differences between the estimation of VA with paired and triple stimuli were not significant (p = 0.136). Triple stimuli yielded higher VAS-pain scores than paired stimuli (p = 0.016). The limits of agreement for the VA using the Bland-Altman method were 7.66/0.629. It seems that the use of additional electrical stimuli is not a recommended solution for the evaluation of VA, because the advantages (i.e., better signal-to-noise ratio) do not outweigh the disadvantages (i.e., an increase in pain).

Altitude differentially alters the force-velocity relationship after 3 weeks of power-oriented resistance training in elite judokas

This study investigated the effects of a 3-week power-oriented resistance training programme performed at moderate altitude on the lower-limb maximal theoretical power and force-velocity (F-V) imbalance of elite judokas. Twenty-two elite male judokas were randomly assigned to either a hypobaric hypoxia or normoxia group. Mechanical outputs from an incremental loaded countermovement jump test were assessed at sea level, before and after training, and 1 week later. Results indicated an increase in the maximal theoretical force and a reduction in the F-V imbalance both at moderate altitude and sea level. Altitude training induced additional benefits when compared to sea level for F-V imbalance (8.4%; CI: 0.3, 17.3%), maximal theoretical power (2.09 W·kg^-1; CI: 0.13, 4.52 W·kg^-1) and force (1.32 N·kg^-1; CI: -0.12, 2.96 N·kg^-1), jump height (3.24 cm; CI: 2.02, 4.80 cm) and optimal maximal theoretical force (1.61 N·kg^-1; CI: 0.06, 3.60 N·kg^-1) and velocity (0.08 m·s^-1; CI: 0.00, 0.17 m·s^-1) after the training period. The hypoxia group achieved their best results immediately after the training period, while the normoxia group achieved them one week later. These results suggest that a power-oriented resistance training programme carried out at moderate altitude accelerates and improves the gains in lower-limb muscle power, while minimizing lower-limb imbalances. Therefore, it seems appropriate to compete immediately after the return to sea level and/or use altitude training as a tool to improve muscle power levels of athletes without tapering goals, especially in highly trained power athletes, since their window of adaptation for further power enhancement is smaller.Highlights A 3-week power-oriented resistance training programme improved lower-limb mechanical outputs of elite judokas both at moderate altitude and sea level; training at moderate altitude increases and accelerates these improvements, reducing athletes' imbalances.It may be optimal for judokas to compete immediately after the return to sea level and/or use altitude training as a tool to improve muscle power levels of athletes without tapering goals, especially in highly trained power athletes, since their window of adaptation for further power enhancement is attenuated.Athletes should ensure they possess adequate strength levels before employing a power-oriented training programme to potentiate further improvements in muscle power.

Diagnostics of tissue involved injury occurrence of top-level judokas during the competition: suggestion for prevention

Background

Judo, as a high-intensity contact sport, may lead to the occurrence of injuries, especially in competitions. This work aims to assess the likelihood of soft and hard tissue injuries in top-level judokas during competition with defining factors that determine the probability of injury occurrence.

Methods

The injuries that occurred in 123 official international competitions from 2005-2019 were recorded by the European Judo Union (EJU) Medical Commission as a survey that was a part of the EJU Injury Registration form with internal consistency shown by a Crombach Alpha of 0.69. This survey data identified factors such as: sex, anatomical localisation of injury, type of injury, tissue involved and mechanisms of the injury. A total of 650 tissue injuries were reported correctly in terms of tissue injury definition.

Results

The most frequent soft tissue injury (STI) reported was a ligament STI (48.15%), closely followed by skin STI (12.15%) and muscles STI (11.38%). In turn, the most frequent hard tissue injury occurred in bones (8.56%). The highest rates of injuries occurred during the fight in the standing position (78%). Injuries in the standing position mainly occurred while executing a throw (25.85%) and followed by the attempt to throw, i.e., the action of reaching the throwing position (22.30%), grip fighting (15.07%), and during falls (14.77%). Opposite to this, fight in groundwork reached only 18.30% soft and hard tissue injuries combined. The ongoing registration of injuries during judo combat and training and the early diagnosis of risk factors for injuries are the basis for the development of effective strategies for injury prevention and further treatment.