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Even though the take‐off in ski jumping is decisive, athletes only have a very limited number of training trials on the actual ski jump to practice under real ski jump conditions. Hence, various imitation jumps aiming to mimic the hill jump are performed during daily training. These imitation jumps should therefore mimic the kinematic pattern of hill jumps appropriately. This study aimed to identify imitation jumps that resemble hill jumps regarding four performance‐related biomechanical criteria: maximal vertical take‐off velocity, maximal knee extension velocity, maximal forward‐ directed angular momentum and anterior shift of the center of mass. Therefore, a three‐dimensional analysis of the take‐off during six different modalities of imitation jumps as well as hill jumps for validation was carried out in nine professional ski jumpers. Imitation jumps from a rolling platform show better agreement than stationary jumps and three out of the four parameters were best resembled via an imitation jump that included ski jumping boots. Thus, non‐hill take‐off training should be performed with complex imitation jumps to mimic the actual ski jump. Except for the vertical take‐ off velocity, we could identify one imitation jump type that is not statistically different to the hill. Consequently, the individual deficiencies of the athletes can be addressed and specifically trained using the appropriate imitation jump. These information about the similarity between imitation jumps and real hill jumps are highly relevant for trainers and athletes in order to effectively design their training programs.

Motor cortical contribution was shown to be important for balance control and for ballistic types of movements. However, little is known about the role of cortical inhibitory mechanisms and even less about long(er)‐term adaptations of these inhibitory processes. Therefore, the aim of the present study was to investigate the role of intracortical inhibition before and after four weeks of explosive or balance training. Two groups of subjects participated for four weeks either in an explosive training programme of the plantar flexor muscles or in a balance training programme on unstable devices. Adaptations in short‐ interval intracortical inhibition (SICI) were assessed by applying paired‐pulse TMS to the soleus muscle during dynamic plantar flexions, balance perturbations and at rest. Furthermore, SICI was assessed for the untrained tibialis anterior muscle. The results show task‐, muscle‐ and group‐specific adaptations in SICI after the training (p = .021) with significantly increased SICI after balance training in the balance task and decreased SICI after explosive training in the ballistic task. The training also caused task‐ and group‐specific behavioural adaptations indicated by improved balance performance after balance training and increased ballistic performance after explosive training. There were no changes in SICI when measured at rest or in the untrained tibialis anterior muscle. This study shows that long(er)‐term training improves the ability to modulate cortical inhibitory processes in a task‐ and muscle‐ specific manner.

ow-load blood flow restriction (LL-BFR) training has gained increasing interest in the scientific community by demonstrating that increases in muscle mass and strength are comparable to conventional high-load (HL) resistance training. Although adaptations on the muscular level are well documented, there is little evidence on how LL-BFR training affects human myotendinous properties. Therefore, the aim of the present study was to investigate morphological and mechanical Achilles tendon adaptations after 14 wk of strength training. Fifty-five male volunteers (27.9 ± 5.1 yr) were randomly allocated into the following three groups: LL-BFR [20–35% of one-repetition maximum (1RM)], HL (70–85% 1RM), or a nonexercising control (CON) group. The LL-BFR and HL groups completed a resistance training program for 14 wk, and tendon morphology, mechanical as well as material properties, and muscle cross- sectional area (CSA) and isometric strength were assessed before and after the intervention. Both HL (+40.7%) and LL-BFR (+36.1%) training induced significant increases in tendon stiffness (P < 0.05) as well as tendon CSA (HL: +4.6%, LL-BFR: +7.8%, P < 0.001). These changes were comparable between groups without significant changes in Young’s modulus. Furthermore, gastrocnemius medialis muscle CSA and plantar flexor strength significantly increased in both training groups (P < 0.05), whereas the CON group did not show significant changes in any of the evaluated parameters. In conclusion, the adaptive change in Achilles tendon properties following low-load resistance training with partial vascular occlusion appears comparable to that evoked by high-load resistance training.NEW & NOTEWORTHY Low-load blood flow restriction (LL-BFR) training has been shown to induce beneficial adaptations at the muscular level. However, studies examining the effects on human tendon properties are rare. The findings provide first evidence that LL-BFR can increase Achilles tendon mechanical and morphological properties to a similar extent as conventional high-load resistance training. This is of particular importance for individuals who may not tolerate heavy training loads but still aim for improvements in myotendinous function.

Increasing evidence suggests that cardiovascular exercise has positive effects on motor memory consolidation. In this study, we investigated whether a single session of high-intensity interval training (HIIT) mitigates the effects of practicing an interfering motor task. Furthermore, learning and interference effects were assessed in the actively trained and untrained limb as it is known that unilateral motor learning can cause bilateral adaptations.Subjects performed a ballistic training and then the HIIT either before (HIIT_before) or after (HIIT_after) practicing an interfering accuracy task (AT). The control group (No_HIIT) did not participate in the HIIT but rested instead. Performance in the ballistic task (BT) was tested before and after the ballistic training, after the exercise and practice of the AT and 24 h later. After ballistic training, all groups showed comparable increases in performance in the trained and untrained limb. Despite the practice of the AT, HIIT_before maintained their BT performance after the high-intensity interval training whereas HIIT_after (trend) & No_HIIT showed prominent interference effects. After 24 h, HIIT_before still did not show any interference effects but further improved ballistic motor performance. HIIT_after counteracted the interference resulting in a comparable BT performance after 24 h than directly after the ballistic training while No_HIIT had a significantly lower BT performance in the retention test. The results were similar in the trained and untrained limb. The current results imply that a single session of cardiovascular exercise can prevent motor interference in the trained and untrained hemisphere. Overall learning was best, and interference least, when HIIT was performed before the interfering motor task.

It is well known that following skill learning, improvements in motor performance may transfer to the untrained contralateral limb. It is also well known that retention of a newly learned task A can be degraded when learning a competing task B that takes place directly after learning A. Here we investigate if this interference effect can also be observed in the limb contralateral to the trained one. Therefore, five different groups practiced a ballistic finger flexion task followed by an interfering visuomotor accuracy task with the same limb. Performance in the ballistic task was tested before the training, after the training and in an immediate retention test after the practice of the interference task for both the trained and the untrained hand. After training, subjects showed not only significant learning and interference effects for the trained limb but also for the contralateral untrained limb. Importantly, the interference effect in the untrained limb was dependent on the level of skill acquisition in the interfering motor task. These behavioural results of the untrained limb were accompanied by training specific changes in corticospinal excitability, which increased for the hemisphere ipsilateral to the trained hand following ballistic training and decreased during accuracy training of the ipsilateral hand. The results demonstrate that contralateral interference effects may occur, and that interference depends on the level of skill acquisition in the interfering motor task. This finding might be particularly relevant for rehabilitation.