Symmetry of proprioceptive sense in female soccer players

Purpose: The purpose of the study was to assess the symmetry of proprioceptive sense among female soccer players when trying to reproduce isometric knee extensions (right and left) and to analyze the impact of a given level of muscle force on proprioception. Methods: The study involved 12 soccer players aged 19.5 ± 2.65 years. Soccer players performed a control measurement of a maximum 3s (knee at the 90°) position in the joint. Subsequently, 70%, 50%, and 30% of the maximum voluntary contraction (MVC) were all calculated and then reproduced by each subject with feedback. Next, the players reproduced the predefined muscle contraction values in three sequences: A – 50%, 70%, 30%; B – 50%, 30%, 70%; C – 70%, 30%, 50% of MVC without visual control. Results: In every sequence, the participants found obtaining the value of 30% of MVC the most difficult. The value they reproduced most accurately was 70% of MVC. Both trial II and trial III demonstrated that the symmetry index SI significantly differed from values considered acceptable (SIRa). In each successive sequence the largest asymmetry occurred while reproducing the lowest values of MVC (30%) (p < 0.05). Conclusion: High level of prioprioceptive sense is important to soccer players due to the extensive overload associated with dynamics stops or changes in direction while running. Special attention should be paid to develop skills in sensing force of varying levels. It was much harder to reproduce the predefined values if there was no feedback

Changes of muscle torque after sprint and endurance training performed on the cycle ergometer

The aim of this work was the specification of the influence of the sprint and endurance training performed on the cycle ergometer on changes of muscle torque. Forty three students of the Academy of Physical Education in Warsaw took part in the study. They were divided into 4 groups and performing the cycle ergometer training consisting of 5 intermittent efforts (2 min break): S10 group- the sprint training (maximal efforts performed with the 10% body weight load); S5 group- the sprint training (maximal efforts conducted with 5% body weight load); W80 group – endurance training (the effort power equal 250 W, single – 3 min effort equal 45 kJ, the pedalling rate – 80 rpm, load 31,0 N appended on the cycle ergometer scale); W45 group – endurance training (the effort power equal 250 W, single – 3 min effort equal 45 kJ, the pedalling rate 45 rpm, load 55.0 N appended on the cycle ergometer scale). The four - week sprint training conducted on the cycle ergometer elicited the increase of the torque of the hip extensors and flexors in S10 and S5 group; extensors of the knee joint in S5 group and plantar flexors in S10 group. The four week endurance training carried out on the cycle ergometer caused the increase of the torque of hip extensors in groups W80 and W45, extensors of the knee joint and plantar flexors in group W45 as well the lowering of the torque of hip flexors in W80 and W45 group and the knee joint flexors in all groups. The significant increase of the sum of the 5 examined muscle groups torque was observed after the sprint training only. Some significant differences between the sprint and endurance training considered hip flexors and the sum of 5 examined muscle groups torque. The endurance training elicited the significant decrease of an hip flexors-to-extensors index value in groups W80 and W45 and of the knee joint in group W45

Comparison of ground reaction forces during the Basic Step on the Core Board platform at various levels of stability

Purpose: The aim of this paper was to examine and compare the changes of ground reaction forces observed during the Basic Step on the Core Board fitness device at various levels of stability. Material and method: The study involved 10 female students. Participants stepped on and off the Core Board 10 times at 3 levels of stability. After completing a series of steps, the Core Board’s stability was modified and the participant repeated the whole series. The measurement platform to examine three components of the reaction force (horizontal in the sagittal and frontal planes, and vertical) was used. Results: The ground reaction force (GRF) observed on the Core Board, in the vertical and horizontal components is higher at all three levels of stability than on the platform without the device. Significant differences in GRF were observed in the horizontal component in the frontal plane (Fz) at all three levels of mobility as well as in impulse, measured on platforms with the device. Conclusion: The results on the Core Board training device present highest horizontal ground reaction forces in frontal plane at the highest level of Core Board mobility and this showing little medio-lateral stability and a more reactive way of movement regulation of the participants. As a consequence of the force patterns found it may be suggested that fitness training concepts should focus more possibly higher strains on the locomotor system most likely caused by changed ground reaction force patterns, an idea that has to be further analyzed with more complex measurement approaches