Eukaryotic genomes transcribe up to 90% of the genomic DNA but only 1–2% of these transcripts encode for proteins, whereas the vast majority are transcribed as non-coding RNAs (ncRNAs). They are divided into short ncRNA, particularly microRNA (miRNA) and small interference RNA (siRNA), and long ncRNAs. Noteworthy, they are unexpectedly stable since they are protected from degradation through different mechanisms: package in exosomes/microvesicles structures, in apoptotic bodies, in HDL lipoprotein, or by RNA binding proteins. For several years already, biomarkers have been used to detect biological disease; in the last years, a requirement appeared to find some of them to unearth the signs of doping. The potential of ncRNAs as a biological candidate is strongly debated and it seems to have become the right tool in the anti-doping hands. In the recent years, the next-generation sequencing (NGS) technology was used by the World Anti-Doping Agency to draft the athlete biological passport (ABP), measuring the circulating miRNAs and applying these new biomarkers in anti-doping. NGS technology does not require any prior knowledge of ncRNAs, but the limit to employ this biomarker to detect performance-enhancing drug use must consider the intrinsic and extrinsic factors that might affect measurements.
Key words: pbiomarkers, doping, HDL, ncRNA, exosome
Purpose. Handgrip strength and arm hang have been recognized as predictors of muscle strength and presented as biomarkers for important health outcomes and overall fitness of an individual. The aim of the study was to investigate the relationship between arm hang and handgrip strength with BMI and skinfold thickness.
Method. The total of 769 children (391 boys and 378 girls) aged 9–15 years underwent a series of anthropometric and strength measurements with the use of standard procedures. Linear regression was applied to assess the relationship of arm hang and handgrip strengths with body mass index and skinfold thickness.
Results. The prevalence of undernutrition and low strength measurements was high (1.7–85%) while the prevalence of overweight and obesity was low (1.5–4.2%) in the Ellisras children aged 9–15 years. Boys showed a significantly higher (p < 0.05) mean arm hang (9.6–13.1 kg) than girls (4.0–5.1 kg) aged 11–15 years. There was a significant (p < 0.05) association between low strength and underweight among Ellisras rural children when unadjusted (OR = 0.650; 95% CI = 0.487–0.867) and adjusted (OR = 0.650; 95% CI = 0.489–0.868) for age and gender.
Conclusions. The prevalence of undernutrition and poor strength was high. An association was observed between arm hang and anthropometric indicators while handgrip showed no significant association with anthropometric indicators. Further studies are needed to investigate the association between strength and undernutrition over time.
Key words: undernutrition, upper body strength, rural South African children
Purpose. The aim of the study was to evaluate the physical activity level, nutritional behaviours, and body silhouette concern in 15–17-year-old boys and girls from Eastern European countries.
Methods. The research, carried out in 2015, involved 2145 secondary school adolescents, including 877 boys and 1268 girls (mean = 16.5, SD = 2.0). The results of the International Physical Activity Questionnaire (IPAQ) and Health Behaviours Questionnaire were analysed.
Results. The questionnaire results allowed to conclude that boys were definitely more active than girls. A significant relationship between physical activity and the number of meals was found. Another significant relationship was observed between higher physical activity in boys who wanted to gain weight and in girls who wanted to lose weight.
Conclusions. Both boys and girls have positive attitudes towards their health with regard to their level of physical activity, nutritional behaviours, and body silhouette concern. A significant relationship was found in the interrelationship among the features considered, with simultaneous gender differentiation.
Key words: school adolescents, physical activity, IPAQ, nutritional behaviours, body silhouette concern
Purpose. The aim of the current investigation was to examine the effects of different footwear on the kinetics and kinematics of performing a 180° cutting manoeuvre.
Methods. Nine male participants performed maximal 180° cut movements in court shoes, minimalist footwear, energy return, and conventional running shoes. Lower limb kinematic data were collected with the use of an 8 camera motion capture system, ground reaction forces were quantified with an embedded force platform, and tibial accelerations were obtained by means of an accelerometer. Differences in kinetics and kinematics between footwear were examined by one-way repeated measures ANOVA.
Results. The results showed that both instantaneous loading rate and peak tibial acceleration were significantly larger in the minimalist (282.91 BW/s and 6.38 g) and court (326.67 BW/s and 6.35 g) footwear compared with the conventional (143.19 BW/s and 5.46 g) and energy return (106.14 BW/s and 4.98 g) footwear. In addition, peak inversion was revealed to be significantly larger in the minimalist (16.36°) than in conventional (11.86°), court (12.61°), and energy return (10.12°) footwear.
Conclusions. These findings indicate that minimalist and court footwear may place athletes at increased risk from injury when performing 180° cut movements.
Key words: footwear, biomechanics, kinematics, change of direction
Purpose. The study aims to examine how shoe insole cushioning can influence coordination pattern and variability in males and females during the landing phase of a jump-landing task.
Methods. Twenty participants (10 males and 10 females) performed jump-landing tasks, and the continuous relative phase (CRP) and the variability of CRP in foot-shank and shank-thigh couplings were determined during the landing phase.
Results. Women represented lower CRP and CRP variability of foot-shank coupling in non-insole conditions (p < 0.05). Shoe insole stiffness had no significant effect on CRP or variability in CRP (p > 0.05).
Conclusions. Although females are characterised by lower coupling variability in non-insole conditions, they do have the capacity to achieve similar coordination patterns and variability as males, in soft and hard conditions. These findings suggest that with changes in the shoe insole, females can achieve similar joint coupling coordination patterns and variability as compared with males under soft and stiff conditions. In addition, as per this study, changes in shoe insole stiffness may not have an impact on coordinative strategies or variability of lower extremity joints couplings during landing.
Key words: coordination, variability, continuous relative phase (CRP), gender, jump-landing, shoe insole
Purpose. Motor coordination is proposed to be a relatively stable age-related construct, unlikely to be influenced by aligned experiential factors such as intensive sport-specific training. The purpose of the study is to investigate if there are differences in motor coordination abilities among young artistic gymnasts, swimmers, and ice hockey players.
Methods. The participants of the study were 508 female and 258 male adolescents (age, M = 12.80, SD = 1.10) comprising artistic gymnasts (n = 463), swimmers (n = 70), and ice hockey players (n = 233). The KTK-test protocol was used to analyse their gross motor coordination abilities.
Results. The results of the study demonstrated that gymnasts scored better than ice hockey players and swimmers in the test of walking backwards along a beam, and better than ice hockey players in total motor coordination, hopping over an obstacle, and the test of moving sideways on wooden boards. However, ice hockey players scored higher than swimmers and gymnasts in the test of jumping from side to side. Subsequently, swimmers obtained better results in the test of moving sideways on wooden boards as compared with ice hockey players.
Conclusions. The study results indicate that intensive sport-specific training may extend young athletes’ motor coordination characteristics in the ability areas representative of the sport in which they engage.
Key words: motor coordination, youth, sports, motor development, ability, KTK-test
Purpose. The aim of the study was to examine the influence of small-sided and conditioned games (SSG) on the internal load (heart rate [HR] and perceived exertion), external load (Global Positioning System variables), and lower limb power (squat jump [SJ] and countermovement jump [CMJ]).
Methods. Six collegiate male soccer players (age 20.3 ± 4.8 years; maximal oxygen uptake 42.9 ± 2.7 ml/kg/min; maximal HR 184.7 bpm) performed three 2-min bouts of 1 vs. 1 and two 3-min bouts of 3 vs. 3 format with a work-to-rest ratio of 1:1.5. Two-way ANOVA with repeated measures tested the effects of bouts and SSG formats on the internal and external load and on the lower limb power.
Results. The 3rd bout had significantly higher HRaverage and %HRmax values than the 2nd bout (p = 0.027 and p = 0.026, respectively). The 1st SSG bout presented higher total distance than the 2nd bout (p = 0.007). The comparison among bouts revealed higher values of pace and player load intensity in the 1st bout than in the 2nd one (p = 0.015 and p = 0.019, respectively). No differences were found in SJ and CMJ among bouts (p = 0.981 and p = 0.307, respectively). SSG formats differed for total distance (p = 0.001; ES = 0.891; longer distance in 3 vs. 3 format), but not for %HRmax (p = 0.953; ES = 0.001).
Conclusions. Physiological and physical responses varied during bouts. Nevertheless, small differences between SSG formats were found. SSG bouts did not have significant impact on the lower limb power.
Key words: football, GPS, training load, neuromuscular fatigue, small-sided games, SSG
Propose. Futsal is a very dynamic indoor team sport. Like in soccer, futsal players perform a number of efforts of different intensity during a match. In each match there are a few return substitutions to allow players to have some rest. The aim of the study was to assess the intensity and energy expenditure of single efforts and the dynamics of restitution after the efforts during successive futsal matches.
Methods. The study consisted in measuring the players' (n = 11) heart rate (HR) during four matches: A, B, C, D. The HR measurement started during a pre-match warm-up and ended 5 min after the match.
Results. The highest intensity of single efforts was noticed in match A. It equalled 90.22 ± 4.90% HRmax and it was the highest in comparison with other matches (p < 0.05). The energy expenditure of efforts performed by players in the matches was 395.11 ± 118.70 kcal. The mean energy expenditure of a single effort was 16.33 ± 5.36 kcal/min. The highest energy expenditure was registered in match A, and it equalled 17.31 ± 4.71 kcal/min during a single effort on the pitch after a return substitution.
Conclusions. The intensity was very high, much higher than that of players’ efforts in 11-a-side soccer. It should be concluded that an appropriate reduction in the time players spend on the pitch during their successive efforts in one match and the consecutive tournament matches can result in reducing the decrease in the effort intensity..
Key words: futsal, intensity of efforts, energy expenditure, heart rate, restitution, RPE
Purpose. The potential of functional training (FT) to improve health is evident. However, regarding post-exercise hypotension (PEH) in older adults, there are few data. The study aimed to determine the cardiometabolic demand imposed by an FT session and evaluate PEH, comparing it with exercise sessions with aerobic and resistance exercises in physically active practitioners.
Methods. Fourteen young (23.3 ± 2 years) and 15 older (68 ± 4 years) adults underwent a control session and FT session randomly determined. Blood pressure, heart rate, and double product were recorded at rest, during exercise, and in every 10 minutes over 60 minutes of recovery. Additionally, we measured the rate of perceived exertion (RPE).
Results. The FT protocol promoted systolic PEH in both groups in the last half of recovery, reaching a reduction of 10.4 ± 4.9 mm Hg in young and 13.4 ± 3.8 mm Hg in older adults (p < 0.05). No differences were observed between the groups (p > 0.05). There were no differences between the groups with reference to RPE at any time (p > 0.05).
Conclusions. A single FT session is able to promote PEH in normotensive young and borderline hypertensive older adults but without changing the RPE in comparison over the time, owing to a great similarity of FT practices in the groups.
Key words: functional training, post-exercise hypotension, blood pressure, elderly, young
University School of Physical Education in Wrocław
al. I. J. Paderewskiego 35
51-612 Wrocław, Poland