The purpose of this article is to review the literature that deals with the biomechanical analysis of the ankle during gait stance phase on slopes, on uneven and rock surfaces, on sand, and on grass surfaces, as well as to present the observed differences. Methods. The literature was searched in the databases of PubMed and Google Scholar, for the years of 2005–2015. The keywords were: biomechanics, gait analysis, ankle joint, stance phase, uphill walking, downhill walking, sand surface, uneven surface, grass surface, and ballast. Results. The kinetic and kinematic gait behaviour is directly influenced by the surface on which it is being performed. The uphill or downhill surfaces, the surfaces of stone, sand, grass, and uneven surfaces have a direct impact on the biomechanics on joints of the lower limb, changing the energy cost, muscle activation, the resulting mechanical work, ground reaction forces and balance, and the parameters of the gait cycle. All these changes are raising many questions about the safety and comfort of these surfaces. In the structures of the foot, ankle and lower leg high compressive and rotational forces are transmitted resulting in injuries in these regions. Conclusions. Each surface has its own advantages and disadvantages, changing the biomechanics of the lower extremity and particularly the ankle. According to the purpose that one wants to achieve they can choose a suitable surface. To prevent injuries and falls, we must choose shoes that fit well, are comfortable with cushioning, and have a feeling neither too hard nor too soft, with laces and low collar.
Key words: biomechanics, ankle joint, stance phase, uphill walking, downhill walking, sand surface, uneven surface, grass surface
Purpose. The study aim was to analyse the relationships between the results of the Timed Up and Go (TUG) test and the Functional Reach Test (FRT), and the temporal and spatial gait parameters determined with the GAITRite system. Methods. The study included 60 healthy, physically active elderly people aged 70.4 ± 5.1 years. The participants’ functional fitness was evaluated with the TUG and FRT, and their temporal and spatial gait parameters – with the GAITRite system. Results. The TUG results correlated inversely with the step length (r = –0.70 and r = –0.61 for the preferred and fast speed, respectively), stride length (r = –0.71 and r = –0.61, respectively), and velocity (r = –0.69 and r = –0.38, respectively). The regression model with these variables explained 43% of variance in the TUG results (p 0.0001). The FRT results correlated positively with the step length (r = 0.61 and r = 0.54, for the preferred and fast speed, respectively), stride length (r = 0.60 and r = 0.56, respectively), and velocity (r = 0.37 and r = 0.38). The regression model with these variables explained 26% of variance in the FRT outcomes. Conclusions. Basic temporal and spatial parameters of gait at the preferred speed, i.e. velocity, step length, stance time, single support time, swing time, and double support time, explain up to 43% of the TUG outcome variance and 26% of the FRT results variance.
Key words: Timed Up and Go test, Functional Reach Test, gait analysis, aging
Purpose. To evaluate the anthropometric profiles of female surfers and to identify whether any anthropometrical factors might predict competitive ranking. Secondly, to evaluate the activity profile of female competitive surfing with respect to environmental conditions using Global Positioning System (GPS) derived measures. Methods. Following institutional ethical approval, 31 female competitive surfers underwent anthropometric assessment (mean age: 20.49, s = 5.32 years; stature: 165.2, s = 4.8 cm; body mass: 63.0, s = 6.8 kg). A subsample (n = 22) wore GPS units during competition at four different locations with varied surfing conditions. Results. The mean somatotype values of the surfers were (Endo-Meso-Ecto) 4.06, 4.15, 2.01. Significant correlations (p < 0.05) were found between the national ranking and triceps, medial calf skinfolds, sum of six skinfolds, body fat percentage, and sum of eight skinfolds. Percentage time sitting, paddling, and riding equalled 62.58 ± 10.18%, 30.70 ± 9.44%, and 6.73 ± 2.91%, respectively. The mean ride time, maximum ride time, total time spent riding, and total distance surfing were significantly correlated with the round of the competition. Furthermore, the number of rides, time spent riding, percentage of total distance surfing, and percentage time riding were correlated with heat placement (p < 0.05). Time spent sitting was associated with poorer heat placements (p < 0.01). Conclusions. Body fat levels are associated with the national ranking in competitive female surfers. The number of waves ridden in a heat, the length of the rides, and activity levels were significantly related to heat placement and competition progression.
Key words: body composition, sports, somatotypes, athletic performance/physiology, muscle, skeletal, body size, body mass index, GPS, wave conditions, competition
Purpose. The study aimed to verify the effects of a simulated taekwondo tournament on vertical jump as well as technical and tactical performance in athletes of the Brazilian national team. Methods. The study involved 10 male Songahm taekwondo athletes. They took part in a simulated tournament in sparring modality, comprising four 2-minute fights with different opponents. Before and after each fight, the athletes performed the Sargent Jump Test and were asked to indicate the rate of the perceived exertion (RPE). In addition, the fights were recorded and some technical and tactical variables were analysed, namely the number of kicks, effectiveness, and technical variety. The analysis of variance for repeated measures with the Bonferroni post hoc test was used, with the significance level set at p < 0.05. Results. No significant differences in the jump height were observed throughout the fights (p = 0.22, trivial effect). The RPE increased over the fights (p < 0.01, large effect); however, no significant differences were obtained after each fight (p > 0.05, trivial effect). All technical and tactical variables remained unchanged over the fights (p > 0.05, trivial-to-small effect). Conclusions. The simulated taekwondo tournament had no effect on vertical jump or technical and tactical performance throughout the fights. The athletes were able to recover the effort perception before each new fight.
Key words: combat sports, stretch-shortening cycle, rate of perceived exertion, motion analysis
Purpose. Sports results in powerlifting have been extensively studied, but there is no analysis of the diagnostic sources of criteria for selecting 19–20-year-old athletes. Therefore, it is important to continue the study of factors affecting performance in powerlifting, not only in individual events, but also in the entire discipline. There were two research objectives in the study: firstly, to identify a set of independent (predictor) variables contributing to sports results (outcome variable) in powerlifting using the least numbers of those variables, and secondly, to develop a biometric regression model describing the sports result. Methods. The study group (n = 30) comprised juniors (aged 19.4 ± 0.7) training powerlifting. The following methods of collecting information were used: observation, survey, and analytical methods of diagnostics: analysis of multiple regression functions, and selection of optimal variables with the use of Hellwig’s algorithm. Results. The optimal set of variables predicting sports results in junior powerlifting consists of nine features. The integral capacity of the selected information sources reached the value of 0.891. Conclusions. It was confirmed that body composition, special physical fitness, and the technique of movement would constitute the optimum combination of explanatory variables of the model. These characteristics have the highest value as diagnostic and selection criteria and should not be overlooked.
Key words: sports performance, youth, assessment, prediction, selection
Purpose. The current investigation aimed to examine the effects of running barefoot and in conventional and barefoot inspired footwear on the loads borne by the tibiofemoral joint. Methods. Fifteen male participants ran at 4.0 m/s over a force platform whilst running barefoot, in barefoot inspired footwear and also in conventional footwear. Lower body kinematics were collected using an eight-camera motion capture system. Peak tibiofemoral force, peak tibiofemoral stress, and tibiofemoral load rate were extracted and compared between footwear via one-way repeated measures ANOVA. Results. The results showed that the tibiofemoral instantaneous load rate was significantly lower in conventional footwear (106.63 BW/s) in comparison with barefoot running (173.87 BW/s), Vibram Five Fingers (160.17 BW/s), Merrell (155.32 BW/s), Inov-8 (167.79 BW/s), and Nike Free (144.72 BW/s). Conclusions. This indicates that running barefoot and in barefoot inspired footwear may place runners at increased risk from running-related tibiofemoral pathologies.
Key words: footwear, biomechanics, tibiofemoral, running
Purpose. The aim of the study was to examine differences in power-velocity characteristics, and the maximal power and height of rise of the body’s centre of mass, measured in the counter-movement jump (CMJ) and the spike jump (SPJ), between judoists, boxers and taekwondo athletes. Methods. The study involved 7 judoists, 6 boxers, and 6 taekwondo athletes. The maximal power and height of jump were measured at CMJ and SPJ jumps. Force-velocity and power-velocity relations were determined on the basis of 5 maximal cycle ergometer exercise bouts at increasing external loads of 2.5, 5.0, 7.5, 10.0, and 12.5% of body weight (BW). Results. The absolute and relative power and velocity recorded for an external force-velocity relationship were similar in the groups. A significant difference was only observed between taekwondo athletes and judoists for absolute power at the external load of 2.5% BW (p < 0.05). The judoists had significantly smaller relative maximal power in SPJ (p < 0.05) and height of rise of the body mass centre in CMJ (p < 0.05) than taekwondo athletes. The relative maximal power in CMJ and height of rise of the body mass centre in SPJ was similar in the groups. Conclusions. In martial arts, training and competition should affect physical characteristics, including jumping and power. The power and velocity recorded for an external forcevelocity relationship were similar in the groups. Judoists and boxers did not differ in terms of power or height of the jumps. Taekwondo athletes developed the biggest power and height of the jumps. This is consistent with the discipline characteristics.
Key words: force-velocity relationship, power, height of jump, spike jump, counter-movement jump, combat athletes
Purpose. The aim was to investigate the relationship between aerobic fitness as ascribed by maximum oxygen uptake (VO2max) and post-exercise recovery after incremental exercise to volitional exhaustion. Methods. A sample of 17 professional cyclists (age 17.4 ± 3.1 years; VO2max 61.1 ± 7.2 ml/min/kg) were recruited. A graded exercise test was administered on a cycle ergometer. Upon termination, the participants remained seated, and oxygen uptake (VO2), minute ventilation (VE), and heart rate (HR) were measured in the 1st, 3rd, and 5th minute of recovery. Results. Post-exercise VO2 dynamics revealed a 69% and 80.9% reduction from VO2max in the 1st and 5th minute, respectively. HR decreased only by 41% of HRmax, in the 5th minute of recovery. A positive correlation between the differential rate of recovery for VO2 and VO2max indicated a dependency between aerobic fitness and recovery potential. Correlative strength decreased with time, and by the 5th minute of recovery a significant correlation was evidenced only between VO2 and VE. Conclusions. As recovery potential is associated with the aerobic fitness level, training effects may be monitored based on the recovery of VO2 and HR to pre-exercise values.
Key words: physical capacity, maximum oxygen uptake, post-exercise recovery, road cyclists
Purpose. The goals of the study were: a) to compare the way that two types of active video games (AVG) influenced physical effort and motivation in young adults; b) to compare direct and indirect instruments and use an indirect instrument (heart rate analysis) as a practical tool to verify physical effort in AVGs. Methods. Initially, 16 healthy but physically inactive young adult males with no AVGs experience took part in the randomized control trial. After the baseline assessments of blood pressure (BP), heart rate (HR), and aerobic capacity (AE), the participants were randomized into two groups: structured AVG (n = 6) and unstructured AVG (n = 7) (3 dropouts). They played 3 sessions a week, during 6 weeks. Direct and indirect metabolic measurements were made. To compare direct and indirect AE, Student t-test was used for related samples. Changes (group × time) in HR, perceived exertion (PE), calculated energy expenditure (EE), calculated metabolic equivalent (MET), and motivation (points) were assessed with the two-way analysis of variance. Results. There were no differences between direct and indirect AE (36.0 ± 5.2 vs 33.9 ± 6.0 ml/kg/min: unstructured; 39.0 ± 5.9 vs 37.7 ± 5.9 ml/kg/min; p > 0.05). No differences were observed in maximal HR, PE, or motivation (p > 0.05). Statistically significant differences referred to average HR, MET, and EE over the sessions (p < 0.05). HR and EE values were higher in structured than in unstructured AVGs. Conclusions. HR and EE responses of structured AVGs turned out higher than those of unstructured AVGs, and the measurements proved efficient to analyse physical effort in AVGs in a long-term perspective.
Key words: exercise, play and playthings, aerobic capacity, heart rate, physical activity
University School of Physical Education in Wrocław
al. I. J. Paderewskiego 35
51-612 Wrocław, Poland