PurposeBack squat (BS) is a popular exercise owing to its capacity to develop lower limb strength. During BS, trunk inclination and knee range of motion (RoM) are relevant aspects of a proper technique, and these movement kinematics parameters can be positively altered with official weightlifting shoes lifting the heel 13 mm above the ground. Wedges are a low-cost alternative to lifting the heel to different heights, but movement kinematics adaptations with higher elevations, above 25 mm, are not well described in the literature. Thus, we compared the effect of different heights of heel wedges on BS kinematics.MethodsFifteen experienced recreational weightlifters (22 ± 5.4 years; 83 ± 11 kg; 179 ± 6 cm; 5 ± 2.1 years of BS experience) were conveniently selected. Three randomized conditions were applied: barefoot (B), 25-mm (W25), and 50-mm wedges (W50). BS movement was assessed by kinematic analysis with an optoelectronic camera system.ResultsAfter ANOVA, the post-hoc indicated significant RoM differences in reducing trunk (F = 27.27; <i>p</i> < 0.01) and increasing knee (F = 16.87; <i>p</i> < 0.01) flexions between conditions. Post-hoc analysis verified decreasing trunk inclination (B > W25 > W50; <i>p</i> < 0.05) and increasing knee (B < W25 < W50; <i>p</i> < 0.05) RoM with increasing wedge height.ConclusionsHigher wedges allowed positive adaptations by promoting a more upright trunk position and greater BS depth. Using a heel wedge can be a low-cost and viable strategy to optimize BS technique in a variety of training settings and contexts.

PurposeHeart rate (HR) monitors have recently started to use photoplethysmography, a technique which measures the light reflected by blood vessels and does not require the use of a chest strap. The aim of this study was to test the validity and accuracy of the Garmin<sup>®</sup> HR monitor, which measures HR at rest and during exercise utilizing the method of photoplethysmography.MethodsThe sample consisted of 28 males aged 18–32 years. Anthropometric measurements were collected and HR was concomitantly monitored with electrocardiography and with the Garmin<sup>®</sup> 735XT<sup>®</sup> device in 2 situations: at rest and during self-selected exercise. Descriptive statistics, linear regression, Bland-Altman plot, mean absolute error (MAE), and mean absolute percentage error (MAPE) were calculated for statistical analysis. Correlations between the HR measurement with electrocardiography and the Garmin<sup>®</sup> monitor at rest and during exercise were obtained (<i>r</i> = 0.93 and <i>r</i> = 0.96, respectively).ResultsThe difference between Garmin<sup>®</sup> and electrocardiography HR values showed an error of –1.2 ± 3.3 bpm (rest), while the average error was positive at 0.7 ± 5.1 bpm. MAE and MAPE at rest equalled 2.2 ± 2.8 bpm and 3.3%, respectively. In addition, MAE and MAPE for exercise were 3.5 ± 3.8 bpm and 3.0%, respectively.ConclusionsThe Garmin Forerunner 735XT can be used at rest, as well as with walking and running activities of light, moderate, and vigorous intensities.

PurposeDribbling is a significant skill in soccer, owing to its effectiveness to create opportunities for scoring, and has been analysed from different perspectives, including the development of talented players. This study proposes a more comprehensive definition than the one earlier applied, considering key elements present in other suggestions found in the literature.MethodsThis study aims to validate the proposed definition, considering evaluations with experts working with events from the 2018 FIFA World Cup Russia<sup>TM</sup> and applying our definition in the analysis of the effectiveness of dribbling actions performed by elite players. We designed a protocol to collect the opinions from experts regarding the classification of events as dribble or non-dribble. To evaluate the quality of experts’ opinions working with the novel dribbling definition, we computed the accuracy, precision, and Krippendorff’s alpha coefficient to measure the agreement between them.ResultsThe obtained results indicate that our definition of dribbling was clear and easily understood by the experts, which suggests that it could be useful to support soccer scouting of dribbling actions. The agreement value showed a near-perfect consensus between experts. We also analysed the effectiveness of dribbling actions considering the number of dribbles and success rates, from which we could observe that 2 CONMEBOL players performed more dribbles than the others.ConclusionsThe proposed 2-dimensional graphs for assessing the effectiveness of players and teams could be a useful tool for coaches to analyse technical actions toward detecting talented players.

PurposeThe purpose of this study was to investigate the effect of stress on movement before and after a computer application-based simulated stress task.MethodsDifferences in the movement of participants were examined by measuring movement quality described by wrist accumulated distance, velocity, acceleration, jerk, and smoothness. Ten high school students performed 3 horizontal and vertical hand circling movements before and after a simulated concentration-based stress task. Blood pressure was measured, and a saliva sample was collected before and after the stress test execution. The participants were instructed to take a 10-minute relaxation period, perform 3 horizontal and vertical circling movements, a 20-minute stress task, and then perform 3 horizontal and vertical movements.ResultsThere were significant differences between before- and after-stress-task levels of cortisol (<i>p</i> < 0.05), heart rate (<i>p</i> < 0.01), smoothness (<i>p</i> < 0.01), and jerk movements (<i>p</i> < 0.05) in the vertical plane. The stress-related variables were lower after the relaxation phase than the stress task. Likewise, movements were smoother and had less jerk in the vertical plane after relaxation.ConclusionsThis study indicates that stress may affect hand movement quality in the vertical plane. Therefore, we recommend that any movement behaviour adaptive therapy should focus on movements in the vertical plane.

PurposeThe purpose of the present study was fourfold: (i) to describe the weekly variations of acute external load measures during a professional soccer season; (ii) to analyse the variability of external load measures within weeks; (iii) to analyse the acute:chronic workload ratio of players during the process; and (iv) to analyse the differences of external load measures between playing positions.MethodsTwenty professional soccer players (age: 24.9 ± 3.5 years; body mass: 71.6 ± 18.7 kg; height: 168.8 ± 41.4 cm) from the same team competing in the First Portuguese League (Europe) voluntarily participated in this study. They were daily monitored with a Global Positioning System (GPS) and the following external load variables were extracted per session: (i) total distance; (ii) running distance; (iii) high-speed running distance; (iv) distance at maximal speed; (v) distance at high accelerations; and (vi) players’ training load. The acute load and acute:chronic workload ratio were weekly calculated for each of the GPS measures.ResultsWeek-by-week variations ranged from –57% to +115%, depending on the playing position and the variable measured. The within-week variability revealed coefficients of variation between 48% and 55%, depending on the measure. Considering the differences in mean load between playing positions, significant differences between players were found for the majority of the variables, with the only exceptions being maximal speed and high accelerations distances.ConclusionsGreat between-week variations in the acute load as well as the variability of load within weeks were found. It was observed that acute load was position-dependent.

PurposeThe purpose of the investigation was to determine the injuries and injury prevention strategies in high school rugby union players, as reported by the coaches.MethodsA cross-sectional, descriptive study was conducted where participants (from fee-paying and no-fee-paying schools) were required to complete an electronically based questionnaire focusing specifically on injuries and injury prevention strategies in male high school level rugby players.ResultsThe results indicated that the most common injured position was the back row, while 60% of all injuries were to the shoulder region. Furthermore, while the majority (75%) of coaches did record injury statistics, only a limited number implemented injury prevention strategies (mainly from fee-paying schools). The most common injury prevention tool reported was ‘strengthening target areas’ConclusionsIt was concluded that all schools should monitor injuries and implement some form of strength and conditioning program to reduce the risk of player injury. Furthermore, it was noted that for this to occur, the education of the coach as well as the player was highly important.

PurposeThe main aim of this study was to evaluate the effect of coordination motor abilities on the sports skill level in elite male badminton players.MethodsThe study group consisted of 12 male players from the Polish national badminton team. the scope of the research included measurement of basic anthropometric features and selected coordination motor abilities. Using the spearman’s rank correlation coefficient, statistically significant cause and effect relations were identified between the sports skill level and the analysed coordination abilities. Multiple determination coefficients were computed to analyse the impact of individual coordination abilities on the sports skill level.ResultsThe multiple determination coefficients showed that the sports skill level of the badminton players was most strongly determined by spatial orientation (ca. 42%), followed by frequency of movements (28%) and kinaesthetic differentiation (ca. 17%).ConclusionsIt seems that these coordination abilities should be taken into careful consideration in technical and tactical training of badminton players since they largely determine their level of achievement.

PurposeAgeing is associated with deterioration and alterations in physical function, affecting community mobility, balance, skills, or daily living activities. The aim of the study was to kinematically analyse the influence of age on balance in young and older adults, as well as to compare the kinematics of the trunk and lumbar regions during Functional Reach Test (FRT).MethodsThe cross-sectional study involved 5 healthy older adults and 6 healthy young adults. Each participant performed FRT instrumentalized with 2 inertial sensors attached in the trunk (T7) and lumbar (L5-S2) regions. Direct (time and displacement) and indirect (velocity and acceleration) kinematic variables, as well as mid-range achieved in FRT were analysed.ResultsThe participants’ mean age was 73.04 ± 3.58 years among the older adults and 23.5 ± 1.52 years among the young adults. Significant differences in time (trunk: –7.61 ± 2.14 s; lumbar: –6.40 ± 1.06 s) and displacement (trunk: 16.33 ± 4.21°) were identified; in the lumbar region, no significant displacement differences were observed (<i>p</i> > 0.05). Similarly, in the partial intervals analysed during FRT (from starting position to maximum displacement/imbalance, and return to the initial position), significant differences (<i>p</i> < 0.05) were revealed in all direct and indirect variables.ConclusionsWhen comparing FRT performance in healthy young and elderly subjects from a kinematic point of view, significant differences were found in the vast majority of kinematic variables analysed in both lumbar and trunk region.

PurposeThe general goal of the study was to investigate the relationship between agility t-test (change of direction speed ability, CODS), 20-m sprint test (S20m) (linear speed ability), and countermovement jump (CMJ) test (lower limb explosive power ability).MethodsThe sample involved 18 elite female football athletes (age: 18.56 ± 2.24 years, height: 169.47 ± 6.48 cm, weight: 63.52 ± 6.85 kg). Pearson correlation coefficients were applied. Multiple linear regression served to explain the relationship between the dependent variable (CODS) and 2 independent variables (S20m and CMJ).ResultsPearson correlation analysis indicated a moderate relationship between CMJ and CODS performance (<i>r</i> = –0.59, <i>p</i> = 0.01) and a very strong significant relationship between S20m and CODS performance (<i>r</i> = 0.80, <i>p</i> = 0.00). The results of multiple linear regression proved that both independent variables (S20m and CMJ) explained about 60.0% (adjusted R2) of the total model variance in relation to the dependent variable (CODS), whereas only S20m significantly (<i>p</i> < 0.05) explained CODS ability.ConclusionsThe study highlighted the impact of explosive power of lower limbs (CMJ) and linear speed capability (S20m) on agility performance (CODS) in our sample. It suggests that the results of agility, linear sprint, and jumping performance seem to have similar determining factors. It is worthwhile to consider these findings in the training process of female elite football players in order to focus on essential training elements of physical fitness.

PurposeTo identify factors constraining functionality and life quality in amyotrophic lateral sclerosis (ALS).MethodsCross-sectional study in 6 ALS patients aged 51.16 ± 8.70 years, with disease duration of 3.16 ± 2.63 years. Amyotrophic Lateral Sclerosis Severity Scale (ALSSS) and Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R/BR) served to evaluate functionality; Amyotrophic Lateral Sclerosis Assessment Questionnaire (ALSAQ-40) analysed life quality. Descriptive statistics was applied to clinical characteristics. The correlation of clinical profile and disease duration with the degree of functionality and life quality was verified by Spearman’s correlation, with values considered significant if <i>p</i> < 0.05 and <i>r</i> > 0.8.ResultsThere was a positive correlation of age with ALSFRS (<i>r</i> = 0.852), disease duration with ALSAQ-40/physical mobility (<i>r</i> = 0.805), ALSFRS-R with ALSSS (<i>r</i> = 0.972), physical mobility with food (<i>r</i> = 0.881), and communication with emotional status (<i>r</i> = 0.947). Negative correlations were observed of age with mobility (<i>r</i> = –0.805) and emotional status (<i>r</i> = –0.876), disease duration with ALSFRS-R (<i>r</i> = –0.858) and ALSSS (<i>r</i> = –0.930), ALSFRS-R with physical mobility (<i>r</i> = –0.978) and food (<i>r</i> = –0.855), ALSSS with physical mobility (<i>r</i> = –0.910) and daily life activity (<i>r</i> = –0.874).ConclusionsLonger disease was associated with lower functionality and poor life quality. Better functionality indicated lower severity and higher life quality in physical mobility and food. Higher severity was bound with poor life quality in physical mobility and daily life activity. We also observed correlations of physical mobility with food, and communication with emotional status.