Movement Competency Training Delivery: At School or Online? A Pilot Study of High-School Athletes.

Movement competency (MC) development of high-school athletes can prepare them for the requirements of physical preparation training and the demands of sport. The aim of this study was to explore the physical effects of and athlete compliance to coach-led versus self-directed training approaches in this population. Thirty-nine high-school athletes (19 male, 14.5 ± 0.3 years old; 20 female, 14.6 ± 0.3 years) were allocated into two groups for a physical preparation program to improve MC. Groups were prescribed either (i) one face-to-face and one online (F2F, n = 18), or (ii) two online (OL, n = 21) sessions per week for 16-weeks. Before and after the intervention, the Athlete Introductory Movement Screen (AIMS) was used to assess MC alongside common physical capacity measures (triple-hop, star-excursion balance, medicine ball throw, 40m sprint and countermovement jump). Dropout left 22 participants with pre-post physical scores. Compliance with online training was low and F2F session attendance moderate. Semi-structured interviews were conducted to assess participant perceptions following the intervention. Assessing individual responses, the F2F group had a higher proportion of positive responders to AIMS scores, yet capacity measures were inconclusive across groups. Face-to-face coaching when acquiring MCs as part of physical preparation, may provide greater positive perceptions towards training compared to self-directed online prescriptions, and thereby greater compliance.

Development and Reliability of an Athlete Introductory Movement Screen for Use in Emerging Junior Athletes.

PURPOSE: A novel 4-task Athlete Introductory Movement Screen was developed and tested to provide an appropriate and reliable movement screening tool for youth sport practitioners. METHODS: The overhead squat, lunge, push-up, and a prone brace with shoulder touches were selected based on previous assessments. A total of 28 mixed-sport junior athletes (18 boys and 10 girls; mean age = 15.7 [1.8] y) completed screening after viewing standardized demonstration videos. Athletes were filmed performing 8 repetitions of each task and assessed retrospectively by 2 independent raters using a 3-point scale. The primary rater reassessed the footage 3 weeks later. A subgroup (n = 11) repeated the screening 7 days later, and a further 8 athletes were reassessed 6 months later. Intraclass correlation coefficients (ICC), typical error (TE), coefficient of variation (CV%), and weighted kappa (k) were used in reliability analysis. RESULTS: For the Athlete Introductory Movement Screen 4-task sum score, intrarater reliability was high (ICC = .97; CV = 2.8%), whereas interrater reliability was good (intraclass correlation coefficient = .88; CV = 5.6%). There was a range of agreement from fair to almost perfect (k = .31-.89) between raters across individual movements. A 7-day and 6-month test-retest held good reliability and acceptable CVs (≤ 10%) for sum scores. CONCLUSION: The 4-task Athlete Introductory Movement Screen appears to be a reliable tool for profiling emerging athletes. Reliability was strongest within the same rater; it was lower, yet acceptable, between 2 raters. Scores can provide an overview of appropriate movement competencies, helping practitioners assess training interventions in the athlete development pathway.

Three-dimensional analysis of a lofted instep kick by male and female footballers.

There is a paucity of data describing the lofted instep kick and little information on the kinematic differences between male and female footballers. This study provides a preliminary investigation into the differences in motion patterns between the sexes. A four-camera motion analysis system videoed 13 amateur footballers (7 female and 6 male) attempting a standardised task that represented a lofted instep kick of approximately 35 m. Footballers performed 20 kicks, with the three trials categorised closest to the standardised distance retained for statistical analysis. Three-dimensional motion patterns for kicks of 35 m illustrated that female footballers produced greater fluctuation in movement patterns for pelvic, hip joint and thoracolumbar spine motion in the frontal plane; thorax and hip joint transverse rotation; and ankle dorsiflexion/plantarflexion motion. Peak hip extension (P = 0.018), impact hip abduction (P = 0.032), impact ankle plantar flexion (P = 0.030) and resultant ball velocity (P = 0.004) differed significantly between sexes. Principle component analysis highlighted associations between kinematic variables related to ball velocity and sex including a reduced hip abduction and increased internal rotation approaching impact, and greater peak knee flexion, respectively. In summary, increased variation in direction of segment motion, increased backswing and formation of a tension arc by females compared to males, may be related to anthropometric, strength and muscle activation differences. Specifically, this exploratory study indicates future research would benefit from exploring trunk, pelvis and hip kinematics and kinetics, and whether training the trunk, pelvis and hip musculature assists female footballers.

Trunk motion and gait characteristics of pregnant women when walking: report of a longitudinal study with a control group.

BACKGROUND: A longitudinal repeated measures design over pregnancy and post-birth, with a control group would provide insight into the mechanical adaptations of the body under conditions of changing load during a common female human lifespan condition, while minimizing the influences of inter human differences. The objective was to investigate systematic changes in the range of motion for the pelvic and thoracic segments of the spine, the motion between these segments (thoracolumbar spine) and temporospatial characteristics of step width, stride length and velocity during walking as pregnancy progresses and post-birth. METHODS: Nine pregnant women were investigated when walking along a walkway at a self-selected velocity using an 8 camera motion analysis system on four occasions throughout pregnancy and once post birth. A control group of twelve non-pregnant nulliparous women were tested on three occasions over the same time period. The existence of linear trends for change was investigated. RESULTS: As pregnancy progresses there was a significant linear trend for increase in step width (p = 0.05) and a significant linear trend for decrease in stride length (p = 0.05). Concurrently there was a significant linear trend for decrease in the range of motion of the pelvic segment (p = 0.03) and thoracolumbar spine (p = 0.01) about a vertical axis (side to side rotation), and the pelvic segment (p = 0.04) range of motion around an anterio-posterior axis (side tilt). Post-birth, step width readapted whereas pelvic (p = 0.02) and thoracic (p < 0.001) segment flexion-extension range of motion decreased and increased respectively. The magnitude of all changes was greater than that accounted for with natural variability with re testing. CONCLUSIONS: As pregnancy progressed and post-birth there were significant linear trends seen in biomechanical changes when walking at a self-determined natural speed that were greater than that accounted for by natural variability with repeated testing. Not all adaptations were resolved by eight weeks post birth.

Initial ball flight characteristics of curve and instep kicks in elite women's football.

Initial ball flight characteristics of curve and instep kicks were investigated. Fifteen international female footballers performed curve and instep kicks from a distance of 20 m from goal and at a 1 m2 target. Seventeen Vicon cameras tracked three-dimensional coordinates of four reflective markers adhered to the ball. Ball flight characteristics were quantified, and the coordinates of the ball relative to the target center were recorded. The lateral launch angle and the angle of the spin axis relative to the horizontal best predicted the horizontal placement of the ball relative to the target. The vertical launch angle, antero-posterior velocity and amount of backspin best predicted the vertical coordinate. Regression models demonstrated how carefully controlled the flight characteristics must be with launch angles constrained within 3° to hit the target. Curve kicks were characterized by significantly greater lateral and vertical launch angles, increased sidespin and spin about the antero-posterior axis, and a more vertical spin axis. This information is beneficial for coaches in training players to achieve the characteristics required to score a goal and avoid a defensive wall. For example, if players consistently kick above or below the target, these findings identify the variables that will help rectify that error.

Curve and instep kick kinematics in elite female footballers.

The three-dimensional kinematics of international female footballers performing a simulated direct free kick (curve kick) were compared with those of an instep kick. Reflective markers attached to the participants were tracked by 17 Vicon cameras sampling at 250 Hz. Foot velocity at ball impact did not differ between the two types of kick, but the way in which foot velocity was generated did differ, with instep kicks using a faster approach velocity and greater linear velocities of the hip and knee, and curve kicks using a greater knee angular velocity at impact. In both types of kick, peak knee angular velocity and peak ankle linear velocity occurred at ball impact, providing biomechanical support to the common coaching recommendation of kicking through the ball. To achieve a curved ball trajectory, players should take a wide approach angle, point the support foot to the right of the intended target (for right-footed players), swing the kicking limb across the face of the goal, and impact the ball with the foot moving upwards and in an abducted position. This information will be useful to coaches and players in identifying the fundamental coaching points necessary to achieve a curved trajectory of the ball compared with the more commonly described instep kick kinematics.

Automatic recognition of gait patterns exhibiting patellofemoral pain syndrome using a support vector machine approach.

Patellofemoral pain syndrome (PFPS) is a common disorder that afflicts people across all age groups, and results in various degrees of knee pain. The diagnosis of PFPS is difficult since the exact biomechanical factors and the extent to which they are affected by the disorder are still unknown. Recent research has reported significant statistical differences in ground reaction forces (GRFs) and foot kinematics, which could be indicative of PFPS, but the interrelationship between many of these measures and the pathology have been absent so far. In this paper, we applied the support vector machines (SVMs) to detect PFPS gait based on 14 GRF and 16 foot kinematic features recorded from 27 subjects (14 healthy and 13 with PFPS). The influence of combined gait parameters on classification performance was investigated through the use of a feature-selection algorithm. The optimal feature set was then compared against the most statistically significant individual features (p < 0.05) found by previous study. Test results indicated that GRF features alone resulted in a higher leave-one-out (LOO) classification accuracy (85.15%) compared to 74.07% using only kinematic features. A hill-climbing feature-selection algorithm was applied to determine the subset of combined kinematic and kinetic features, which provided optimal classifier performance. This subset, which consists of six features (two from GRF and four from foot kinematic features), provided an improved LOO accuracy of 88.89% . The optimal feature set detected by the SVM, which best identified gait characteristics of PFPS, was found to be closely related to inferential statistical analysis with the added distinction that the SVM could potentially be deployed as an automated system for detecting gait changes in patients with PFPS.

A longitudinal study of the effect of pregnancy on rising to stand from a chair.

Rising to stand from a chair becomes more difficult to perform as pregnancy progresses, which may lead to altered biomechanics affecting the musculoskeletal demands on the body segments. The kinematic and kinetic adaptations in the lower limbs and trunk as pregnancy progresses are unknown. Nine maternal subjects were investigated using an eight-camera motion analysis system and two force plates, four times throughout pregnancy and once post-birth during rising to stand. Twelve nulliparous female subjects were used to establish natural variation with retesting over the time period. The maternal subjects used temporal-spatial, kinematic and kinetic strategies to widen the base of support, minimize propulsion, increase motion of the thoracic segment and minimize anterior trunk-thigh apposition. A fear of postural instability may have made the subjects more cautious, and as they were able to adequately flex the trunk forward, propulsion was minimized in favor of maintaining upright terminal balance.

Detecting trunk motion changes due to pregnancy using pattern recognition techniques.

There are anatomical changes during pregnancy due to the increased and altered mass distribution in the trunk that could lead to changes in gait. There is little research, however, regarding adaptations in trunk motion with pregnancy. In this paper, we investigated the application of two pattern recognition techniques: support vector machine (SVM) and linear discriminant analysis (LDA) to detect differences in trunk kinematics, when walking, between women in late pregnancy and nulliparous (control) women. Test results indicate that the SVM can identify the trunk motion of pregnant women from their counterparts with a better accuracy compared to the LDA (71.43% vs 28.57% respectively). Furthermore, with a feature selection technique applied, the accuracy improved to 95.24% % using only 2 features namely the pelvic sagittal plane displacement and thoracic lateral tilt displacement at heel contact. The results suggest that for better detection of trunk motion changes in pregnant women, non-linear analysis may be required. The SVM was able to effectively differentiate pregnancy related trunk motion changes during a walking task which may indicate altered musculoskeletal loads with potential for injury or pain.

Rising to stand from a chair: symmetry, and frontal and transverse plane kinematics and kinetics.

Although literature in relation to rising to stand from a chair is extensive, there is limited information on symmetry and motion in the frontal and transverse planes. Ground reaction forces (GRF), lower limb angular displacements and moments, and the thoracolumbar and cervicothoracic spine regions angular displacements around the vertical and antero-posterior axes (respectively, the transverse and frontal planes) were investigated in 12 females. Right to left symmetry and the trial-to-trial consistency of all variables was also investigated. Able-bodied participants demonstrated frontal and transverse plane displacement and moments in the lower limbs and the trunk, and mediolateral GRFs, during rising to stand from a chair. The results of this study also support the concept of a consistent individual strategy for frontal plane motion during rising to stand and highlight the strategies used to maintain side-to-side stability during the motion. The potential importance of this was reflected in the similar magnitudes of the GRFs required to stabilise the median plane orientation of the centre of mass and that required for the forward propulsion of the body. Asymmetrical net applied moments support the concept of side dominance in components of apparently symmetrical motor tasks.

Identification of patellofemoral pain syndrome using a Support Vector Machine approach.

Patellofemoral pain syndrome (PFPS) is a common disorder resulting in varying degrees of knee pain. The diagnosis of PFPS is difficult since the exact biomechanical factors involved in the disorder are still unknown. Recent research has reported significant differences in rearfoot kinematics and foot ground reaction forces (GRFs) which could be indicative of PFPS, but the inter relationship between these measures and the pathology have been inconclusive so far. In this paper, we investigate Support Vector Machines (SVM)'s potential to classify gait patterns with PFPS using 14 GRF and 16 rearfoot kinematic features. Test results indicated that using GRF features alone resulted in a leave one out (LOO) classification accuracy of 85.15% compared to 74.07% using kinematic features. A hill climbing feature selection algorithm was subsequently applied to determine the subset of features which improved classifier performance. This reduced subset consisted of 6 features from a combination of GRFs and kinematic features, and provided a maximum LOO accuracy of 88.89% in detecting the PFPS gait.

Evaluation of the ability of physical therapists to palpate intrapelvic motion with the Stork test on the support side.

BACKGROUND AND PURPOSE: Clinical indicators of pelvic girdle dysfunction are limited. However, research has shown that the pattern of intrapelvic motion is altered during single-leg support in subjects with pelvic girdle pain (PGP). Functionally, no relative motion should occur within the pelvis during load transfer, whereas anterior rotation of the innominate bone relative to the sacrum occurs during weight bearing in the presence of PGP. The aim of this study was to investigate whether the pattern of intrapelvic motion could be detected reliably during a new clinical assessment test for functional load transfer: the Stork Test on the support side. SUBJECTS AND METHODS: Three physical therapists were randomly assigned to palpate the motion of the innominate bones and sacrum in 33 subjects during the Stork Test on the support side. The direction of bone motion was indicated on 2-point and 3-point scales. RESULTS: When a 2-point scale was used, intertherapist agreement on the pattern of intrapelvic motion occurring during load transfer showed good reliability (left kappa=.67, right kappa=.77), and the percentage of agreement was high (left=91.9%, right=89.9%). A 3-point scale resulted in moderate reliability for both the left and the right sides (left kappa=.59, right kappa=.59), and the percentage of agreement decreased to 82.8% (left) and 79.8% (right). DISCUSSION AND CONCLUSION: The ability of the physical therapists to reliably palpate and recognize an altered pattern of intrapelvic motion during the Stork Test on the support side was substantiated. The ability to distinguish between no relative movement and anterior rotation of the innominate bone during a load-bearing task was good. Further research is needed to determine the validity of this test for detecting pelvic girdle dysfunction.

Tibia and rearfoot motion and ground reaction forces in subjects with patellofemoral pain syndrome during walking.

Abnormal subtalar joint function and the consequent rotation of the tibia during walking are thought to contribute to patellofemoral pain syndrome (PFPS). The purpose of this study was to measure rearfoot and tibia motion, and the ground reaction force (GRF) during the stance phase of walking in subjects with PFPS and compare them to healthy subjects. A four camera motion analysis system with a single force plate was used to investigate rearfoot motion relative to the tibia in three planes, the tibial transverse plane rotation and the GRF during the stance phase of walking in 13 female subjects diagnosed with PFPS and 14 healthy females. Analysis showed significantly delayed peak rearfoot eversion (p=0.02), and earlier occurrence of peak dorsiflexion (p=0.02) for the PFPS group. Furthermore, significantly lower peak medial GRF (p=0.03), minimum vertical GRF trough (p=0.02) and the second vertical GRF peak (p=0.01) were found in the PFPS group. Tibial transverse rotation was not shown to be different in PFPS subjects. However, there was prolonged rearfoot eversion during the stance phase of walking. The earlier appearance of rearfoot dorsiflexion as well as the lower GRFs indicate altered propulsive function of the foot during supination.

Relationship between static posture and rearfoot motion during walking in patellofemoral pain syndrome: effect of a reference posture for gait analysis.

The reference posture used in angular motion calculations may play an important role in the relationship found between static posture and rearfoot motion in the frontal plane in a clinical population such as patients with patellofemoral pain syndrome. This study examined the relationship between rearfoot inversion and eversion during the stance phase of walking and the static relaxed standing measurement in women (aged 18 years and older) with patellofemoral pain syndrome and controls and examined the influence of the reference posture used when calculating dynamic motion. Two reference postures were investigated: vertical alignment between the rearfoot and the lower leg and relaxed calcaneal standing. When using the latter reference posture, a significant correlation was found between the static relaxed standing measurement and peak eversion in controls only. When using the vertical alignment reference posture, significant correlation was found only in the patellofemoral pain syndrome group for peak eversion and inversion. The positive relationship found in the patellofemoral pain syndrome group between dynamic angular measures, based on a neutral reference posture, and static relaxed standing indicated that for subjects with patellofemoral pain syndrome, the clinical rearfoot measurement of relaxed standing can be used to explain the pattern of rearfoot motion during walking.

Frontal plane motion of the rearfoot during a one-leg squat in individuals with patellofemoral pain syndrome.

Abnormal motion of the foot has been suggested to be a potential contributor to the medial collapse of the knee seen in individuals with patellofemoral pain syndrome during a one-leg squat. Rearfoot frontal plane range of motion and peak angle were investigated during a one-leg squat in patients with patellofemoral pain syndrome compared with controls. A significant increase in the peak eversion angle was found for the patellofemoral pain syndrome group compared with controls (P = .02). Increased rearfoot eversion may contribute to the knee medial collapse observed in these patients because it may lead to tibial abduction relative to the femur. Nevertheless, further research is required to investigate the causal relationship because it remains unclear whether rearfoot eversion instigates the medial collapse of the knee.

The Application of an Exploratory Factor Analysis to Investigate the Inter-Relationships amongst Joint Movement During Performance of a Football Skill.

Many studies have investigated the kinematics of sports skills with the majority describing the kinematics of the technique or investigating significant kinematic variables that affect performance. Many sports skills are complex three-dimensional movements involving many joints. However, few studies have investigated the relationships between kinematic variables during performance of such skills. The aim of this study was to investigate the inter- relationships among three-dimensional kinematic variables during performance of a lofted instep soccer kick. A motion analysis system was used to collect kinematic data for 13 skilled amateur soccer players attempting a standardised lofted instep kick. Three-dimensional angular displacement patterns were reported for the thoracolumbar spine and right hip joints. Two-dimensional angular displacement data was reported for the right knee and ankle joints. An exploratory rather than confirmatory factor analysis was applied, as there is currently no established theory regarding the kinematics of a lofted instep kick. Factors were extracted using the Maximum Likelihood Solution and orthogonally rotated using Varimax with Kaiser normalisation. The inter-relationship among biomechanical variables within the seven extracted factors was analysed with each factor revealing previously unknown inter-relationships among variables for different aspects of the kick. The use of exploratory factor analysis has shown the complex three-dimensional kinematic inter-relationships for a lofted instep kick. An understanding of these relationships could prove useful to coaches when instructing, and in the development of coaching programmes related to the lofted instep kick. Key PointsMotion analysis of lofted instep kick.Inter-relationship among biomechanical variables within 7 factors analysed.Each factor revealed previously unknown inter-relationships among variables for different aspects of the kick.understanding these relationships could prove useful to coaches in the development of the lofted instep kick.

Reliability of an individually molded shank shell for measuring tibial transverse rotations during the stance phase of walking.

Use of a shank shell has been shown to estimate tibial transverse rotations better than skin-mounted markers. However, the day-to-day reliability of the transverse tibial rotations using an individually molded shank shell has not been previously investigated. This study examined the between-tests and trials reliability of an individually molded shank shell for measuring peak tibial internal and external rotations, time of peak values, and tibia range of motion during 5 walking trials. The trial-to-trial reliability of tibial transverse rotations was measured in 14 healthy individuals while the test-retest reliability was measured in 10 persons on two occasions. Trial-to-trial reliability for peak transverse rotations, time of peak values, and tibia range of motion ranged from ICC (3,1) 0.59-0.95. The PCA between trials showed that 88-99 % of values were within 3 degrees of agreement. Test-retest reliability for peak rotations, tibia range of motion, and time of peak values ranged from ICC (3,1) 0.70-0.89 with SEM 1.6-2.21 degrees , 0.021 %, and 0.034 %, respectively. The PCA between tests showed that 70-100 % of values were within 3 degrees of agreement. The use of an individually molded shell and the close attachment of the shank shell to the individual's shank resulted in reliable test-retest and trial-to-trial data.

The stance phase of walking during late pregnancy: temporospatial and ground reaction force variables.

The purpose of this study was to investigate temporospatial and ground reaction force variables in the stance phase of walking during late pregnancy. An eight-camera motion-analysis system was used to record 13 pregnant women at 38 weeks' gestation and again 8 weeks after birth. In late pregnancy, there was a wider step width, and mediolateral ground reaction force tended to be increased in a medial direction. The center of pressure moved more medially initially and less anteriorly at 100% of stance in late pregnancy. The differences suggest that women may adapt their gait to maximize stability in the stance phase of walking and to control mediolateral motion.

An investigation of a reference posture used in determining rearfoot kinematics for both healthy and patellofemoral pain syndrome individuals.

The choice of a reference posture is important when investigating rearfoot motion in clinical populations. The reference posture used may affect the magnitude of the peak angles and therefore may not enable comparison of the rearfoot kinematics across different populations. This study examined the relationship between the rearfoot frontal plane pattern of motion and three reference postures during the stance phase of walking in healthy and patellofemoral pain syndrome (PFPS) subjects. The three reference postures investigated were: Relaxed Standing posture, subtalar joint neutral position (STJN) and when the calcaneus and the lower leg were vertically aligned (Vertical Alignment). The rearfoot inversion/eversion during the stance phase was measured in 14 healthy subjects and 13 subjects with diagnosed PFPS using three dimensional motion analysis with the three different reference postures. The graphs of rearfoot inversion/eversion motion were overlaid with the angle at the rearfoot in the static posture and any intersection between the static angle and rearfoot motion was noted. An ANOVA showed significant differences in static posture between the groups for Relaxed Standing (p = 0.01), and STJN (p = 0.02). For both groups, with Relaxed Standing as a reference posture, the mean rearfoot pattern of motion did not intersect the Relaxed Standing static angle during the stance phase. The use of Vertical Alignment reference posture, however, showed an intersection of this reference posture through the rearfoot pattern of motion. The use of the Vertical Alignment reference posture also generated a typical rearfoot motion pattern for both groups and therefore it may be an appropriate reference posture for both healthy and PFPS individuals. Key PointsThe use of the three reference postures resulted in shifting of the curve of the rearfoot frontal plane pattern of motion. The shift of the curve is important in identifying the magnitude of rearfoot peak motion during the stance phase.The use of Vertical Alignment reference posture only, generated a typical rearfoot motion pattern for both groups and therefore it may be an appropriate reference posture for both healthy and PFPS individualsThe use of Relaxed Standing and STJN as reference postures would not be recommended due to their poor test retest reliability.