Krzysztof Buśko

The aim of this study was to evaluate body composition and the level of selected motor skills of the lower limbs in female participants, including 13 deaf students who are physically inactive (age 16.11 ± 1.53 years), 8 deaf soccer players (age 16.13 ± 1.25 years), and 16 hearing soccer players (age 16.41 ± 1.23 years). No significant differences were observed among the groups in terms of body weight, height, or measured perimeters. Regarding body composition, significant differences were identified between female soccer players and deaf physically inactive girls. Regular training appeared to result in similar 35-m sprint times among deaf and hearing female soccer players. A post-hoc analysis revealed no statistically significant differences between hearing and deaf female soccer players across most variables, except for peak torque relative to body mass during flexion at an angular velocity of 180°·s⁻¹ and lower limb muscle force expressed relative to body mass in the counter-movement jump (CMJ) test. The isokinetic testing of the moment of force indicated that deaf girls (from both groups) produced higher values than hearing soccer players. Both groups of deaf participants achieved lower jump heights values but generated higher power in the akimbo counter-movement jump (ACMJ) and CMJ tests compared to hearing soccer players. The higher values observed in some biomechanical variables among deaf female soccer players, as well as deaf non-active female students, may be influenced not only by training experience but also by factors such as proprioception and musculoskeletal compensation.

Study aim : The aim of the study was to evaluate the differences in strength and jumping abilities of adolescent soccer players playing in different positions on the field. Material and methods : The study included 41 adolescent (14.53 ± 0.68 years old) soccer players: 6 goalkeepers (GK), 13 defenders (DF), 15 midfielders (MD) and 7 strikers (ST). We measured peak torques (PT), total work (TW), and average power (AP) developed by the knee flexors and extensors under isokinetic conditions at angular velocities of 300°·s ⁻¹ , 180°·s ⁻¹ and 60°·s ⁻¹ on a Biodex dynamometer, as well as jump height (h), jump depth (d) and power (P _max ) on a force plate. Results : There was a statistically significant difference in body height between GK (181.17 ± 10.40 cm) and MD (165.60 ± 9.07 cm). PT, AP, TW, h, and P _max showed no statistically significant differences between the positions on the field. Significant correlations between jumping height and isokinetic measurements of the quadriceps were found in MD (p < 0.05). Correlations between jump power and isokinetic measurements of the quadriceps were found in all types of jumps in the DF and MD groups, whereas no correlation in the bounce counter-movement jump was shown by GK and ST (p > 0.05). MD showed an inverse relationship between the PT, AP, and TW at movement velocities of 300°·s ⁻¹ and 180°·s ⁻¹ , and the jump depth in the akimbo counter-movement jump and counter-movement jump. Conclusion : The observed differences in correlations between the positions are likely due to the different tasks assigned to the specific position during the match.

The aim of the study was to determine the relationship between changes in physiological tremor after exercise and changes in the traction properties of the stretch reflex indirectly assessed using the Hoffmann reflex test. The research involved 19 young men practicing canoe sprint (age 16.4 ± 0.7 years, body mass 74.4 ± 6.7 kg, body height 182.1 ± 4.3 cm, training experience 4.8 ± 1.6 years). During resting tests, Hoffmann reflex measurements were performed from the soleus muscle, physiological tremor of the lower limb, and the blood lactate concentration was determined. Then, a graded test was carried out on the kayak/canoe ergometer. Immediately after the exercise and in the 10th and 25th minute following the exercise, Hoffmann’s reflex of the soleus muscle was measured. The physiological tremor was measured at 5, 15 and 30 min after exercise. Blood lactate concentrations were determined immediately after physiological tremor. Both the parameters of Hoffmann’s reflex and physiological tremor changed significantly after exercise. There were no significant interrelationships between Hoffmann reflex measurements and physiological tremor in resting and post-exercise conditions. No significant correlation was detected between changes in physiological tremor and changes in Hoffmann reflex parameters. It is to be assumed that there is no connection between a stretch reflex and a physiological tremor.

The aim of the study was to determine reference graphs of power spectral density functions of forearm physiological tremor and to compare their parameters in the male and female population of young athletes from various sports. One hundred fifty-nine (159) female (15.7 ± 2.1 years, 59.8 ± 8.1 kg, 169.1 ± 7.5 cm) and 276 male (16.4 ± 1.9 years 72.7 ± 10.3 kg and 180.9 ± 8.7 cm) youth athletes participated in the study. Forearm tremor was measured accelerometrically in a sitting position. Power spectrum density (PSD) function was calculated for each individual tremor waveform. Because of right skewness of power distribution, the PSD functions were subjected to logarithmic transformation. Average log-powers in low (2–4 Hz) and high (8–14 Hz) frequency ranges and mean frequencies in those ranges were analyzed. Tremor log-powers for male were greater than for female athletes (p < 0.001), while frequencies of spectrum maxima did not differ from each other. Frequencies of spectrum maxima correlated (p < 0.001) with age (r = 0.277 and 0.326 for males and females, respectively). The obtained reference functions may be utilized in order to quantify and assess tremor size and its changes evoked by stress and fatigue, which can be applied for selection and training monitoring in sports, but also in medicine for detection and diagnosis of pathologic tremor in young individuals.

The aim of the study was to build a fuzzy model of lower limb peak torque in an isokinetic mode. The study involved 93 male participants (28 male deaf soccer players, 19 hearing soccer players and 46 deaf untraining male). A fuzzy computational model of different levels of physical activity with a focus on the lower limbs was constructed. The proposed fuzzy model assessing lower limb peak torque in an isokinetic mode demonstrated its effectiveness. The novelty of our research lies in the use of hierarchical fuzzy logic to extract computational rules from data provided explicitly and then to determine the corresponding physiological and pathological mechanisms. The contribution of our research lies in complementing the methods for describing physiology, pathology and rehabilitation with fuzzy parameters, including the so-called dynamic norm embedded in the model.

Summary: Study aim : The aim of the study was to examine the differences in physical fitness between deaf female soccer players and their deaf peers who did not practise any sport. Material and methods : The research involved 13 deaf female soccer players and 16 deaf untrained girls. Physical fitness was assessed by a jump test and the Eurofit test. In the jump test, each participant performed an akimbo counter-movement jump (ACMJ), a counter-movement jump (CMJ) and a spike jump (SPJ) on a force plate. The following trials of the Eurofit test were performed: flexibility – sit-and-reach; static strength – hand grip; functional strength – bent arm hang (arm and shoulder muscular endurance); explosive strength – standing broad jump; and trunk strength – sit-ups (abdominal muscular endurance). Results : Soccer players jumped significantly higher than untrained females in the ACMJ, CMJ, and SPJ, and developed significantly higher power of the CMJ. Relative power developed in the ACMJ and SPJ did not differ between the examined groups. Soccer players were physically fitter than girls who did not play any sport. Significant differences between the groups were observed for all measured trials except for the bent arm hang. Conclusions : Hearing loss does not significantly determine the physical development or physical fitness of deaf people. Playing sports improves the physical fitness of deaf people in comparison with untrained deaf people.

The study aim was to determine if a difference exists in skinfold thickness measured by two interchangeable approaches; (1) supraspinale skinfold recommended in the Heath-Carter method and (2) iliac crest skinfold measurement. The question arises as to whether each approach has a similar or different effect on endomorphy determination, and whether there is a possibility to estimate the supraspinale skinfold based on other skinfold measurements. A group of 186 male and 161 female students participated in this study. Anthropometric examination included all somatic measurements, as recommended in the Heath-Carter protocol, and the iliac crest skinfold measurement. Estimation of the supraspinale skinfold was performed based on the multiple linear regression procedure. Skinfold thickness measured in the supraspinale and iliac crest differed (p2 = 0.724, SE = 0.9 mm and R² = 0.947, SE = 2.3 mm for men and women, respectively). Two common skinfold approaches produced different measurements between the supraspinale and iliac crest skinfolds, which subsequently affected estimated endomorphy. Regression equations for supraspinale skinfold enabled correction of endomorphy in the case of improperly applied measurement (i.e. iliac crest) and thus, could allow for uniform somatotype estimation according to Carter and Heath approach.

The aim of the study was to determine changes in the magnitude and direction of secular trends in body height, body weight, body mass index (BMI) and fat percentage in university students from a university of technology and a university of physical education in a period of 50 years. The data were derived from the examinations of male students from the Warsaw University of Technology, conducted four times, in 1959, 1971, 1994, 2011, and male students from the Józef Piłsudski University of Physical Education in Warsaw, who were examined in 1963, 1972, 1996, and 2012. Body height, body weight and thickness of 2 skinfolds (triceps skinfold and abdomen skinfold) were measured. Body mass index (BMI) and fat percentage (FAT%) were also calculated. Current university students are taller and heavier than their peers from the previous decades, with BMI remaining within the reference range. A substantial increase in fat percentage was found in both groups. Over the period of fifty years, mean fat percentage in students from the university of technology increased by 6.3% (F1,3 = 116.56, p < 0.001, η² = 0.3736), whereas this increase in the students from the university of physical education rose by 3.5% (F1,3 = 72.94, p < 0.001, η² = 0.3181). Changes in secular trends in the students from both universities are likely to be linked to the dynamic economic and systematic transformation in Poland observed in the period of the last 50 years. The period of economic transformations in the last decade was more conducive to physical development of university students than the previous period of economic crises.

Purpose: The aim of the study was to investigate changes of power-velocity relationship and muscular strength of female volleyball players during preparatory period and competition season. Methods: The study was conducted on eleven female volleyball players: age 21.6 +/- 1.7 years, body height 177.9 +/- 4.7 cm, body mass 71.3 +/- 6.6 kg. Power-velocity relationship was determined by means of five maximal 10-second cycloergometer efforts with external loads equal to: 2.5, 5, 7.5, 10 and 12.5% of body weight (BW). The joint torque of flexors and extensors of an elbow, shoulder, hip, knee and trunk was measured using a torque meter. The measurement were taken before (I) and after (II) the preparatory period, after the first (III) and second (IV) competitive season. Results: The power with a load equal to 2.5, 5.0, 7.5, 10.0% BW increased significantly after first and second competitive season. The sums of joint torque for the lower and upper limb changed insignificantly. In the case of the right upper limb, sum of the joint torques was significantly reduced by 9.5% between measurement I and IV. Sum of the left upper limb was significantly decreased by 9.8% between measurement I and II. Sum of the joint torque of the trunk was significantly increased between measurements I and II, III and IV by 12.9%, 12.3% and 11.2%, respectively. Conclusion: Obtained results may suggest that selection of the training loads was adequate for training power output and muscle strength of lower limbs but too little emphasis was placed on development of strength in the muscles of the upper limbs.

Orysiak, J, Mazur-Różycka, J, Busko, K, Gajewski, J, Szczepanska, B, and Malczewska-Lenczowska, J. Individual and combined influence of ACE and ACTN3 genes on muscle phenotypes in polish athletes. J Strength Cond Res 32(10): 2776–2782, 2018—The aim of this study was to examine the association between angiotensin-converting enzyme (ACE) and α-actinin-3 (ACTN3) genes, independently or in combination, and muscle strength and power in male and female athletes. The study involved 398 young male (n = 266) and female (n = 132) athletes representing various sport disciplines (ice hockey, canoeing, swimming, and volleyball). All were Caucasians. The following measurements were taken: height of jump and mechanical power in countermovement jump (CMJ) and spike jump (SPJ), and muscle strength of 10 muscle groups (flexors and extensors of the elbow, shoulder, hip, knee, and trunk). The insertion-deletion (I/D) polymorphism of ACE and the R577X polymorphism of ACTN3 were typed using polymerase chain reaction (PCR) and polymerase chain reaction—restriction fragment length polymorphism (PCR-RFLP), respectively. The genotype distribution of the ACE and ACTN3 genes did not differ significantly between groups of athletes for either sex. There was no association between ACE and ACTN3 genotypes (alone or in combination) and sum of muscle strength, height of jump or mechanical power in both jump tests (CMJ and SPJ) for male and female athletes. These findings do not support an influential role of the ACE and ACTN3 genes in determining power/strength performance of elite athletes.