Plyometric training is characterized by high-intensity exercise which is performed in short term efforts divided into sets. The purpose of the present study was twofold: first, to investigate the effects of three distinct plyometric exercise protocols, each with varying work-to-rest ratios, on muscle fatigue and recovery using an incline-plane training machine; and second, to assess the relationship between changes in lower limb muscle strength and power and the biochemical response to the three exercise variants employed. Forty-five adult males were randomly divided into 3 groups (n = 15) performing an exercise of 60 rebounds on an incline-plane training machine. The G0 group performed continuous exercise, while the G45 and G90 groups completed 4 sets of 15 repetitions, each set lasting 45 s with 45 s rest in G45 (work-to-rest ratio of 1:1) and 90 s rest in G90 (1:2 ratio). Changes in muscle torques of knee extensors and flexors, as well as blood lactate (LA) and ammonia levels, were assessed before and every 5 min for 30 min after completing the workout. The results showed significantly higher (p < 0.001) average power across all jumps generated during intermittent compared to continuous exercise. The greatest decrease in knee extensor strength immediately post-exercise was recorded in group G0 and the least in G90. The post-exercise time course of LA changes followed a similar pattern in all groups, while the longer the interval between sets, the faster LA returned to baseline. Intermittent exercise had a more favourable effect on muscle energy metabolism and recovery than continuous exercise, and the work-to-rest ratio of 1:2 in plyometric exercises was sufficient rest time to allow the continuation of exercise in subsequent sets at similar intensity.

The study aimed to analyse the effectiveness of two variants of 8-week strength training (hypertrophy, strength) with different modes of resistance. Healthy male subjects (n=75) were allocated to five groups of equal size: hypertrophy training with a variable cam (Hyp-Cam), hypertrophy training...

Study aim: In alpine skiing, balance is one of the key elements that determine the effectiveness of the ride. Because of ski boots, the foot and ankle joint complex is excluded from the process of maintaining the stability of the body. The aim of the study was to determine to what extent a few days of skiing activities and the level of technical skills affect the skiers’ level of postural stability

Purpose: Snowboarding requires a lateral positioning of the body. Moreover, a person must continuously control their balance and use this in order to manoeuvre on the slope applying properly pressure on the lower limb closest to the nose of the board (the leading leg). The present study is an attempt to determine the interdependencies between side preference while snowboarding and laterality when performing other tasks. The dynamic stability in the neutral standing position, as well as in the lateral positions (left or right) was also evaluatedMethods: The survey participants (100 active snowboarders) answered a set of questions concerning laterality while carrying out basic everyday tasks and while doing sports. The respondents were divided into two groups based on their preferred leading side in snowboarding. Additionally, in the case of 34 people, muscle torques values of the lower limbs were measured under static conditions and the postural stability was evaluated using AccuSway AMTI platform and Biodex Balance System platform.Results: Over 90% of the participants declared right-handedness and right-footedness. However, with regard to snowboarding, only 66% indicated their right leg as leading. No significant dependence was found between the directional stance on the board and the leading hand, dominant leg, or leading eye. The stability measurements revealed statistically significant differences between the neutral stance and the lateral positioningConclusions: Based on the study results, it may be assumed that the declared directional stance on the snowboard is not contingent on the person’s basic laterality, and that the lateral stance on the board significantly affects the posture control.

Introduction. Snowboarding is a sports discipline in which postural control is key to achieving an effective technique. The body is positioned sideways on the snowboard, with only the head facing forward. This study evaluated the effect of several days of intense snowboarding on the parameters of static and dynamic body stability in persons with different levels of skill. Material and methods. A nine-day snowboarding course was designed and conducted with beginner (N = 16) and advanced snowboarders (N = 14) in the mountains in winter. Before and after the course, dynamic body stability was measured on a Biodex Balance System (USA) platform with an unstable surface, and static body stability was measured on a FreeMed Sensor Medica (Italy) stabilometric platform. Results. Measurements on an unstable surface showed significantly weaker (p < 0.01) values of body stability in a lateral stance in the snowboarding stance than in a forward stance and a significant (p < 0.05) improvement in performance after the course. On a stable surface, the improvement in performance (p < 0.05) occurred only among the beginners, in the snowboard basic position. Conclusions. The results confirm that snowboarding, or continuous unstable balance, improves postural control, which leads to the conclusion that the lateral stance on the snowboard is a clearly disruptive factor in natural postural control. This constitutes a considerable difficulty, especially for beginners, who in addition to learning new technical skills, must adapt to continuously shifting balance.

The study aimed to compare the effectiveness of two variants of 4 weeks plyometric training involving jumping up (dominance of concentric muscle work, UP) and jumping down (dominance of eccentric muscle work, DOWN) the stairs. Twenty-six young men were divided into two groups: UP (n = 13) and DOWN (n = 13). Control measurements of the muscle torques, vertical jumps, and creatine kinase (CK) activity were performed every week. The training resulted in significant changes (p < 0.001) in the muscle torques of the hip extensors (Delta approximate to 20% in both groups) and plantar flexors (Delta(UP) = 25%, Delta(DOWN) = 33%), but in the muscle torques of the knee extensors a significant (p < 0.001) increase occurred only in the group jumping down the stairs (Delta(DOWN) approximate to 15%). Furthermore, a significant increase (p < 0.001) of the height of the vertical jump was noted in the study only in the group jumping down (Delta(DOWN) = 8%). Training with the dominance of eccentric work caused greater weekly changes in the activity of creatine kinase in the plasma. The study confirmed that the exercise involving jumping on the stairs is viable in plyometric training, as it is an effective means of training the strength of the muscles of the lower limbs and vertical jump height, with a greater share assigned to jumping down consecutive steps.