Inside Leg Research Articles

Model Pembelajaran Kooperatif TGT Untuk Meningkatkan Hasil Belajar Passing Kaki Bagian Dalam Pada Permainan Sepak Bola

The aim of this research is to improve the learning outcomes of inside foot passing in soccer games through the Teams Games Tournament (TGT) model. The method used is classroom action research. The subjects of this research were all 35 students at MI Al Hidayah. The sequence of this research includes: 1. Planning, 2. Implementation, 3. Observation, 4. Reflection. Data collection uses lesson plans, observation sheets and documentation. Data analysis uses percentage descriptions. The research results show that in cycle 1 the average inside leg passing skill was 59, 5 students or 14% got a score above 75 (KKM). Meanwhile, in cycle 2 the average inside foot passing skill was 81%, there were 27 students who got a score above 75 (KKM) or 77%. The results of this research can conclude that applying the affective teams games tournament (TGT) learning model can improve learning outcomes for inside-leg passing in MI Al Hidayah students.

ANALISIS KETEPATAN AKURASI PASSING KAKI BAGIAN DALAM SEPAK BOLA PADA SISWA SEKOLAH SEPAK BOLA (SSB) INDONESIA MUDA KECAMATAN SELUMA UTARA KOTA BENGKULU

This study aims to determine the accuracy analysis of inside leg passing accuracy for Indonesia Muda Football School (SSB) students. This research is a qualitative descriptive research. The population in this study was 20 students at the Indonesia Muda Football School (SSB), North Seluma. The test instrument used is the inside leg passing test using a cone.The results of this research test show that the accuracy of passing the inside foot of football for students at the Indonesia Muda Seluma Utara Football School (SSB) in 2023 is in the very good category, 5% (1 student). with good category, 30% (6 students). with the medium category, 45% (9 students). less category, 15% (3 students). And the very poor category, 5% (1 student).

Pelatihan Menggunakan Kaki Bagian Dalam Pada Permainan Sepak Bola Untuk Siswa/I Madrasah Ibtidaiyah [MI] Mathlaul Anwar Pangkalan Kelas 1 Dan 2

The foot kick method is generally the inside leg kick technique used to provide short passing that suits them. the most dominant movement in running, the main goal is to score as many goals as possible towards the opponent's goal. The purpose of this study was to determine the effect of deep kick training on shooting accuracy in soccer matches. The research method used is a literature search covering several sources such as primary and secondary sources. With the results of research from various sources to be able to conclude that the method of practicing kicking the inside of the leg affects the accuracy of the shot. "There is an effect of training to kick the ball with the inside of the foot, which affects shooting accuracy in soccer matches, using this method of oblique training. Thus, it can be concluded that how to kick the inside of the leg has a significant effect on shooting accuracy in a soccer match

Estimation of Joint Moments During Turning Maneuvers in Alpine Skiing Using a Three Dimensional Musculoskeletal Skier Model and a Forward Dynamics Optimization Framework.

In alpine skiing, estimation of the joint moments acting onto the skier is essential to quantify the loading of the skier during turning maneuvers. In the present study, a novel forward dynamics optimization framework is presented to estimate the joint moments acting onto the skier incorporating a three dimensional musculoskeletal model (53 kinematic degrees of freedom, 94 muscles). Kinematic data of a professional skier performing a turning maneuver were captured and used as input data to the optimization framework. In the optimization framework, the musculoskeletal model of the skier was applied to track the experimental data of a skier and to estimate the underlying joint moments of the skier at the hip, knee and ankle joints of the outside and inside leg as well as the lumbar joint. During the turning maneuver the speed of the skier was about 14 m/s with a minimum turn radius of about 16 m. The highest joint moments were observed at the lumbar joint with a maximum of 1.88 Nm/kg for lumbar extension. At the outside leg, the highest joint moments corresponded to the hip extension moment with 1.27 Nm/kg, the knee extension moment with 1.02 Nm/kg and the ankle plantarflexion moment with 0.85 Nm/kg. Compared to the classical inverse dynamics analysis, the present framework has four major advantages. First, using a forward dynamic optimization framework the underlying kinematics of the skier as well as the corresponding ground reaction forces are dynamically consistent. Second, the present framework can cope with incomplete data (i.e., without ground reaction force data). Third, the computation of the joint moments is less sensitive to errors in the measurement data. Fourth, the computed joint moments are constrained to stay within the physiological limits defined by the musculoskeletal model.

The Impact of Circular Exercise Diameter on Bone and Joint Health of Juvenile Animals.

Simple SummaryIn many equestrian disciplines, circular exercise is utilized to train, exercise, and compete with horses and can vary in gait, as well as diameter. This study aimed to determine if circular exercise diameter impacts animal health. Calves have previously been used as a terminal skeletal model of juvenile horses, allowing for the collection of musculoskeletal samples that are not acceptable from horses. Calves exercised on a small circle (12-m clockwise), large circle (18-m clockwise), treadmill, or served as non-exercised controls. Exercise was performed at a walking speed, starting at 5 min per day and increasing 5 min weekly until reaching 30 min per day during the 7-week study. The response to exercise was monitored in the forelimb bones and joints. The small circular exercise group was found to have bone diameters that differed between the right and left fused third and fourth metacarpi, and between lateral and medial proximal phalanx bones. Cartilage glycosaminoglycan content was greater in the outside leg of the small circle exercise calves than the inside leg, with no differences noted within other treatments. These differences suggest that altering circular exercise diameter can impact bone and joint health, and that larger diameter circles may prevent asymmetric loading between inside and outside legs.Circular exercise is used in many equestrian disciplines and this study aimed to determine if circle diameter impacts juvenile animal forelimb bone and joint health. On day 0, 24 calves at 9 weeks of age were assigned the following exercise treatments: small circle (12 m clockwise), large circle (18-m clockwise), treadmill, or non-exercised control. Exercise was initiated at 1.1–1.5 m/s for 5 min/d and increased 5 min weekly until reaching 30 min/d. On day 49, synovial fluid was collected from multiple joints, cartilage was collected from the proximal surface of fused third and fourth metacarpi (MC III and IV), and forelimbs underwent computed tomography scans. A statistical analysis (PROC mixed) was performed in SAS 9.4. The inside leg of the small circle treatment had a larger MC III and IV dorsopalmar external diameter than the outside (p = 0.05). The medial proximal phalanx had a greater mediolateral diameter than the lateral proximal phalanx of the small circle treatment (p = 0.01). Fetlock nitric oxide was greater in the large circle and treadmill treatments (p < 0.0001). Cartilage glycosaminoglycan concentration was greater in the outside leg of the small circle exercise treatment than the inside leg (p = 0.03). Even at slow speeds, circular exercise diameter can impact joint and bone health, but faster speeds may have greater alterations.

Reference values of inside leg length and inside leg length to stature ratio for Japanese children, 0–12 years of age

Background Large datasets of detailed anthropometric measurements are scarce in children. The Japanese Standard Association 1978–1981 survey provides a rare opportunity to use high quality data from Japanese children. Aim To construct inside leg length (ILL) and inside leg length to stature ratio (ILL/S) reference centile curves for Japanese children. Subjects and methods The study sample consisted of 14,825 boys and 14,577 girls age 0–18 years for stature and weight measurements, and 9064 boys and 8796 girls age 0–12 years for ILL measurements, who participated in the 1978–1981 national survey on body sizes. LMS method was used to construct the reference centile curves. The reference centile curves for stature, weight, ILL, and ILL/S were compared to those of British children. Results The L, M, and S reference values for Japanese children are presented for stature, weight, ILL, and ILL/S. Compared with British children of 0–12 years of age, Japanese children of 0–12 years of age had shorter median stature, shorter median ILL, and shorter median ILL/S. Conclusion We present the first reference values for ILL and ILL/S in Japanese children. Japanese children had relatively shorter legs compared to British children from infancy.

Automatic Estimation of Body Measurements to Extract the Size and Body Shape

This paper presents the research results of automatic estimation of the neck girth and inside leg to extract the size and body shape from the male sizing system table. The data used in the study is the 3D scan file *.obj from the 3D body scanner. The author uses the interpolation and optimization method in the algorithm to automatically extract 2 primary dimensions combined with the fuzzy logic method to extract sizes, body shapes. Besides, rotate matrix method combines with the optimal function used to write an algorithm to estimate the neck girth, inside leg measurements. Furthermore, a simple approach based on vertices and surface normal vectors data and optimal search was adapted to estimate the neck girth and inside leg measurements. These extraction results will be linked to the algorithm of the fuzzy logic to run for the automated process. This automatic algorithm will be very useful in face-to-face clothing purchases or online or for garment manufacturers in reducing shopping time and choosing sizes to design samples for customers.

Asymmetries in Ground Reaction Forces During Turns by Elite Slalom Alpine Skiers Are Not Related to Asymmetries in Muscular Strength.

The ground reaction forces (GRF) associated with competitive alpine skiing, which are relatively large, might be asymmetric during left and right turns due to asymmetries in the strength of the legs and torso and the present investigation was designed to evaluate this possibility. While skiing a symmetrical, 20-gate slalom course, the asymmetries of 9 elite alpine skiers were calculated on the basis of measurements provided by inertial motion units (IMU), a Global Navigation Satellite System and pressure insoles. In addition, specialized dynamometers were utilized to assess potential asymmetry in the strength of their legs and torso in the laboratory. In total, seven variables related to GRF were assessed on-snow and eight related to strength of the legs and torso in the laboratory. The asymmetries in these parameters between left and right turns on snow were expressed in terms of the symmetry (SI) and Jaccard indices (JI), while the asymmetries between the left and right sides of the body in the case of the laboratory measurements were expressed as the SIs. The three hypotheses to be tested were examined using multivariable regression models. Our findings resulted in rejection of all three hypotheses: The asymmetries in total GRF (H1), as well as in the GRF acting on the inside and outside legs (H2) and on the rear- and forefeet GRF (H3) during left and right turns were not associated with asymmetries in parameters related to muscular strength. Nevertheless, this group of elite slalom skiers exhibited significant asymmetry between their right and left legs with respect to MVC during ankle flexion (0.53 ± 0.06 versus 0.60 ± 0.07 Nm/kg, respectively) and hip extension (2.68 ± 0.39 versus 2.17 ± 0.26 Nm/kg), as well as with respect to the GRFs on the inside leg while skiing (66.8 ± 7.39 versus 76.0 ± 10.0 %BW). As indicated by the JI values, there were also large asymmetries related to GRF as measured by pressure insoles (range: 42.7–56.0%). In conclusion, inter-limb asymmetries in GRFs during elite alpine skiing are not related to corresponding asymmetries in muscular strength. Although our elite athletes exhibited relatively small inter-limb asymmetries in strength, their asymmetries in GRF on-snow were relatively large.

Muscle-tendon unit length changes in knee extensors and flexors during alpine skiing

ABSTRACT This study characterised the thigh muscle-tendon unit length variations (MTUv) in elite alpine skiing. MTUv were modelled for seven muscles from knee and hip angles in 17 national team skiers during 1602 cycles (546 Slalom (SL), 908 Giant-Slalom (GS), 136 Super-Giant (SG) and 12 Downhill (DH) cycles). The biarticular rectus femoris showed a dynamic pattern on both legs, especially in SL. On the other side, vastii displayed a stable length on the inside leg in all disciplines (37–46% of the cycle), contrasting with their dynamic behaviour on the outside leg being quasi-static for only 3% (SL) to 27% (DH) of the cycle. SL showed the largest amplitude of MTUv followed by GS, SG and DH. For vastus lateralis, MTUv was ~60%Lr.s−1 in SL but only ~12%Lr.s−1 in DH. In SL, a fine desynchronisation between both joints led to nearly constant MTUv (slow lengthening lasting ~45-51% of the cycle) for the biarticular hamstrings separated by faster variations during turn switch from outside to inside leg. In summary, biarticular MTUv were not characterised by single-joint behaviours, suggesting that extrapolating contraction regimen from knee joint only is not accurate in alpine skiing.

The effect of curve running on distal limb kinematics in the Thoroughbred racehorse.

During racing, injury is more likely to occur on a bend than on a straight segment of track. This study aimed to quantify the effects of galloping at training speeds on large radius curves on stride parameters and limb lean angle in order to assess estimated consequences for limb loading. Seven Thoroughbred horses were equipped with a sacrum-mounted inertial measurement unit with an integrated GPS, two hoof-mounted accelerometers and retro-reflective markers on the forelimbs. Horses galloped 2–4 circuits anticlockwise around an oval track and were filmed at 120 frames per second using an array of ten cameras. Speed and curve radius were derived from GPS data and used to estimate the centripetal acceleration necessary to navigate the curve. Stride, stance and swing durations and duty factor (DF) were derived from accelerometer data. Limb markers were tracked and whole limb and third metacarpus (MCIII) angles were calculated. Data were analysed using mixed effects models with a significance level of p < 0.05. For horses galloping on the correct lead, DF was higher for the inside (lead) leg on the straight and on the curve. For horses galloping on the incorrect lead, there was no difference in DF between inside and outside legs on the straight or on the curve. DF decreased by 0.61% of DF with each 1 m s-2 increase in centripetal acceleration (p < 0.001). Whole limb inclination angle increased by 1.5° per 1 m s-1 increase in speed (p = 0.002). Limb lean angles increase as predicted, and lead limb function mirrors the functional requirements for curve running. A more comprehensive understanding of the effects of lean and torque on the distal limb is required to understand injury mechanisms.

Curve Sprinting in Soccer: Kinematic and Neuromuscular Analysis.

Sprinting in curvilinear trajectories is an important soccer ability, corresponding to ~85% of the actions performed at maximum velocity in a soccer league. We compared the neuromuscular behavior and foot contact-time between outside leg and inside leg during curve sprinting to both sides in soccer players. Nine soccer players (age=23±4.12 years) performed: 3×Sprint linear, 3×Sprint right curve, and 3×Sprint left curve. An ANOVA with repeated measures was used to compare the differences between inside and outside leg, and Cohen's d was used to calculate the effect-size. Considering the average data, the performance classification (from best to worst) was as follows: 1. Curve "good" side (2.45±0.11 s), 2. Linear (2.47±0.13 s), and 3. Curve "weak" side (2.56±0.17 s). Comparing linear with curve sprinting, inside leg recorded significant differences ("good" and "weak"; effect size=1.20 and 2, respectively); in contrast, for outside leg, there were no significant differences ("good" and "weak"; effect size=0.30 and 0.49, respectively). Electromyography activity showed significant differences (p≤0.05) during curve sprinting between outside (higher in biceps femoris and gluteus medius) and inside leg (higher activity in semitendinosus and adductor). In summary, inside and outside leg play different roles during curved sprints, but inside leg is more affected by the change from straight to curve sprint.

On-Field Ski Kinematic According to Leg and Discipline in Elite Alpine Skiers.

This study used wireless technology to investigate joint kinematic characteristics of the four alpine skiing disciplines. Knee and hip angles were measured in 20 national team alpine skiers during 253 ski runs under FIS regulation, including: 85 Slalom (SL), 123 Giant Slalom (GS), 29 Super Giant Slalom (SG), and 16 Downhill (DH). Data were analyzed by outside (OL, n = 2,087) and inside leg (IL, n = 2,015). The proportion of concentric and eccentric phases (extension and flexion respectively for the knee extensors) as well as the proportion of the quasi-isometric phase defined between ±20°.s−1 depended on the discipline in interaction with the IL/OL (p < 0.001). The results showed a lower knee quasi-isometric duration on OL in SL (11%) than other disciplines (DH: 38%; SG: 42%; GS: 34%, p < 0.001, d > 1.8), suggesting a highly dynamic style. Quasi-isometric mode was significantly longer on OL than IL in GS (34 vs. 20%, p < 0.001, d = 1.16) and SG (42 vs. 28%, p < 0.001, d = 1.11) but was significantly longer on IL than OL in SL (19 vs. 11%, p < 0.001, d = 0.64). Thus, GS and SG showed similarities, with a significantly faster knee eccentric mean angular velocity on IL compared to OL (GS −58 vs. −54°.s−1, SG −52 vs. −45°.s−1, p < 0.001, d ≥ 0.22) whereas SL showed an opposite pattern (−72 vs. −89°.s−1, p < 0.001, d = 1.10). The quasi-isometric phase was overlooked in previous studies but is crucial to consider. The current data may be used to train the outside and inside leg specificities incorporating discipline-specific contraction modes and exercises.

Are Existing Monocular Computer Vision-Based 3D Motion Capture Approaches Ready for Deployment? A Methodological Study on the Example of Alpine Skiing.

In this study, we compared a monocular computer vision (MCV)-based approach with the golden standard for collecting kinematic data on ski tracks (i.e., video-based stereophotogrammetry) and assessed its deployment readiness for answering applied research questions in the context of alpine skiing. The investigated MCV-based approach predicted the three-dimensional human pose and ski orientation based on the image data from a single camera. The data set used for training and testing the underlying deep nets originated from a field experiment with six competitive alpine skiers. The normalized mean per joint position error of the MVC-based approach was found to be 0.08 ± 0.01 m. Knee flexion showed an accuracy and precision (in parenthesis) of 0.4 ± 7.1° (7.2 ± 1.5°) for the outside leg, and −0.2 ± 5.0° (6.7 ± 1.1°) for the inside leg. For hip flexion, the corresponding values were −0.4 ± 6.1° (4.4° ± 1.5°) and −0.7 ± 4.7° (3.7 ± 1.0°), respectively. The accuracy and precision of skiing-related metrics were revealed to be 0.03 ± 0.01 m (0.01 ± 0.00 m) for relative center of mass position, −0.1 ± 3.8° (3.4 ± 0.9) for lean angle, 0.01 ± 0.03 m (0.02 ± 0.01 m) for center of mass to outside ankle distance, 0.01 ± 0.05 m (0.03 ± 0.01 m) for fore/aft position, and 0.00 ± 0.01 m2 (0.01 ± 0.00 m2) for drag area. Such magnitudes can be considered acceptable for detecting relevant differences in the context of alpine skiing.

Asymmetry of the leg stretcher force high-performance female and male juniors in sweep rowing

ABSTRACTThe geometry of sweep rowing causes an asymmetrical movement with uneven force distribution on both sides of the body. The aim of this study was to investigate the asymmetry of the stretcher force for junior women and men. Four rowing eight-crews (N = 32) completed a stroke rate test and a 2000 m race. The rowing angle, the handle force and the stretcher force for the inside (oarside) and outside (non oarside) leg were measured. In both sub-samples, the outside leg stretcher force was higher than the inside leg stretcher force. The women rowed with higher symmetry index of stretcher force (26.8 ± 19.7%) than the men (8.6 ± 15.9%). This asymmetry was reduced with increasing stroke rate but increased with physical fatigue in the course of the rowing race. The transmission to the oar via trunk and arms is associated with unequal loading of the pelvis and lumbar spine. Female and male sweep rowers with high asymmetry of the stretcher force should use appropriate strength and technique training to reduce the asymmetry and the risk of low back pain.

Effects of feeding juniper as a roughage on feedlot performance, carcass measurements, meat sensory attributes, and volatile aroma compounds of yearling Rambouillet wethers1,2.

The majority of U.S. lambs are born during late winter or early spring, which can create downstream variability in carcass quality if commercial lamb harvest is to be relatively constant throughout the year. Flavor is an important quality determining characteristic of sheep meat and is influenced, in part, by animal age at harvest. However, management practices to mitigate the risk of objectionable flavors in meat from old crop lambs or yearlings are not well known. Yearling (16.8 ± 0.14 mo) Rambouillet wethers were assigned to 1 of 3 treatment groups, which consisted of feeding a 20% ground sorghum-sudangrass hay diet for 40 d (JUN0; n = 10), a 20% ground juniper diet for 40 d (JUN40; n = 10), or a 20% ground hay diet for 20 d followed by a 20% ground juniper diet for 20 d (JUN20; n = 10). Wethers were harvested on day 41 and a whole bone-in loin and a boneless inside leg roast were fabricated from one side each of carcass. After grilling (loin chop) or convection air roasting (leg roast), trained sensory panel evaluation and measurement of aroma volatiles by gas chromatography/mass spectrometry were performed. Treatment diet did not affect (P ≥ 0.17) wether feedlot performance, dressing percentage, or loin eye area. However, wethers fed JUN0 tended (P = 0.06) to have greater back fat depth than wethers fed JUN20 or JUN40. No trained sensory panel trait of loin chop samples was affected (P > 0.10) by treatment. Leg roasts from JUN0 and JUN20 wethers had greater (P = 0.01) lamb identification sensory score than JUN40. Benzaldehyde, 1-heptanol, and 1-octanol concentrations were greater (P < 0.05) and decanal and nonenal concentrations were less (P < 0.05) in loin chops from JUN0 compared with JUN40 wethers. Additionally, the terpenes cedr-8-ene, gamma muurolene, and widdrene tended to be greater (P < 0.07) in loin chops from JUN20 and JUN40 than JUN0 wethers. The 2-pentyl-furan concentrations were greatest (P = 0.03) in leg roasts from JUN40 wethers. Like the loin chops, cedr-8-ene, gamma-muurolene, toluene, and widdrene were greater (P < 0.05) in leg roasts from wethers fed either of the juniper diets compared with JUN0. Yearling wethers can be finished on a feedlot diet containing 20% juniper for up to 40 d prior to harvest with no impact on feedlot performance, carcass characteristics, nor negative impact on sensory attributes or volatile compounds of either grilled loin chops or roasted legs.

Whole-body and segment angular momentum during 90-degree turns

BackgroundTurning is a frequently performed, asymmetric task of daily living. The asymmetric nature makes turning challenging to perform while maintaining balance. Research questionHow do healthy individuals maintain dynamic balance, quantified as whole-body angular momentum, during a 90-degree turn compared to straight-line walking? MethodsThe kinematics of sixteen healthy individuals were tracked during walking in a straight-line and during left and right 90-degree turns at a comfortable pace. Whole-body and segment angular momenta were calculated and the relative contributions of the legs, arms, pelvis and head/trunk to whole-body angular momentum were evaluated. ResultsAverage whole-body angular momentum was different during turning compared to straight-line walking in all planes of motion. The initiation of a turn required generation of whole body angular momentum in all three planes of motion, which was counteracted at the end of the turn by a generation of angular momentum in the opposite direction in the frontal and sagittal planes. Transverse plane momentum was always directed in the turn direction. All segment groups, except for the inside leg, had a greater magnitude of angular momentum during turning compared to straight-line walking. The outside leg and head/trunk segments were the largest contributors to frontal and transverse plane whole-body angular momentum. SignificanceUnderstanding how body segments contribute to maintaining balance during a 90-degree turn can be useful for designing rehabilitation paradigms for people who have difficulty turning or impaired balance.

Locomotion pattern and foot pressure adjustments during gentle turns in healthy subjects

People suffering from locomotor impairment find turning manoeuvres more challenging than straight-ahead walking. Turning manoeuvres are estimated to comprise a substantial proportion of steps taken daily, yet research has predominantly focused on straight-line walking, meaning that the basic kinetic, kinematic and foot pressure adaptations required for turning are not as well understood. We investigated how healthy subjects adapt their locomotion patterns to accommodate walking along a gently curved trajectory (radius 2.75m). Twenty healthy adult participants performed walking tasks at self-selected speeds along straight and curved pathways. For the first time for this mode of turning, plantar pressures were recorded using insole foot pressure sensors while participants’ movements were simultaneously tracked using marker-based 3D motion capture. During the steady-state strides at the apex of the turn, the mean operating point of the inside ankle shifted by 1 degree towards dorsiflexion and that for the outside ankle shifted towards plantarflexion. The largest change in relative joint angle range was an increase in hip rotation in the inside leg (>60%). In addition, the inside foot was subject to a prolonged stance phase and a 10% increase in vertical force in the posteromedial section of the foot compared to straight-line walking. Most of the mechanical change required was therefore generated by the inside leg with hip rotation being a major driver of the gentle turn. This study provides new insight into healthy gait during gentle turns and may help us to understand the mechanics behind some forms of impairment.

Age-related changes in continuous kinematic and kinetic waveforms in typical developing children and adults

Turning is a requirement for most locomotor tasks; however, knowledge of the biomechanical requirements of successful turning is limited. Therefore, the aims of this study were to investigate the spatio-temporal and lower-limb kinematics of 90° turning. Seventeen typically developing children, fitted with full body and multi-segment foot marker sets, having performed both step (outside leg) and spin (inside leg) turning strategies at self-selected velocity, were included in the study. Three turning phases were identified: approach, turn, and depart. Stride velocity and stride length were reduced for both turning strategies for all turning phases (p < 0.03 and p < 0.01, respectively), while stance time and stride width were increased during only select phases (p < 0.05 and p < 0.01, respectively) for both turn conditions compared to straight gait. Many spatio-temporal differences between turn conditions and phases were also found (p < 0.03). Lower-limb kinematics revealed numerous significant differences mainly in the coronal and transverse planes for the hip, knee, ankle, midfoot, and hallux between conditions (p < 0.05). The findings summarized in this study help explain how typically developing children successfully execute turns and provide greater insight into the biomechanics of turning. This knowledge may be applied to a clinical setting to help improve the management of gait disorders in pathological populations, such as children with cerebral palsy.

Maximum-speed curve-running biomechanics of sprinters with and without unilateral leg amputations.

On curves, non-amputees' maximum running speed is slower on smaller radii and thought to be limited by the inside leg's mechanics. Similar speed decreases would be expected for non-amputees in both counterclockwise and clockwise directions because they have symmetric legs. However, sprinters with unilateral leg amputation have asymmetric legs, which may differentially affect curve-running performance and Paralympic competitions. To investigate this and understand the biomechanical basis of curve running, we compared maximum curve-running (radius 17.2 m) performance and stride kinematics of six non-amputee sprinters and 11 sprinters with a transtibial amputation. Subjects performed randomized, counterbalanced trials: two straight, two counterclockwise curves and two clockwise curves. Non-amputees and sprinters with an amputation all ran slower on curves compared with straight running, but with different kinematics. Non-amputees ran 1.9% slower clockwise compared with counterclockwise (P<0.05). Sprinters with an amputation ran 3.9% slower with their affected leg on the inside compared with the outside of the curve (P<0.05). Non-amputees reduced stride length and frequency in both curve directions compared with straight running. Sprinters with an amputation also reduced stride length in both curve-running directions, but reduced stride frequency only on curves with the affected leg on the inside. During curve running, non-amputees and athletes with an amputation had longer contact times with their inside compared with their outside leg, suggesting that the inside leg limits performance. For sprinters with an amputation, the prolonged contact times of the affected versus unaffected leg seem to limit maximum running speed during both straight running and running on curves with the affected leg on the inside.

Peak Ankle Muscle Activity of Faster and Slower Basketball Players during the Change-of-Direction Step in a Reactive Cutting Task

Peak Ankle Muscle Activity of Faster and Slower Basketball Players during the Change-of-Direction Step in a Reactive Cutting Task Study Background: Basketball requires frequent direction changes during match-play under reactive conditions. The ankle dynamic stabilizer muscles (Tibialis Anterior [TA], Peroneus Longus [PL], Peroneus Brevis [PB], soleus) may influence cutting effectiveness. This study examined whether ankle muscle activity differentiated between faster and slower basketballers in a reactive cutting task. Methods: Eighteen male basketballers completed six reactive trials (randomized three left and three right) of the Y-shaped agility test. Electromyography measured peak normalized (against 10-meter sprint muscle activity) activity (nEMG) of the TA, PL, PB, and soleus for both the inside and outside legs during the change-ofdirection step (first step past the trigger gate that initiated the cut). The outside leg was the leg furthest from the target gate; the inside leg was the closest. The faster direction change (left or right) was defined as the preferred or non-preferred cut direction. Preferred cut direction time was used to divide the sample into faster (n=9) and slower (n=9) groups. A one-way analysis of variance (p<0.003 for multiple comparisons) and effect sizes calculated any betweengroup differences in cutting and muscle activity. Data was pooled for a correlation analysis (p<0.05) between test times and ankle muscle nEMG. Results: The faster group was quicker in the preferred and nonpreferred cuts, although there were no significant between-group differences in muscle activity, and no significant correlations. There was a large effect for the 83% greater inside leg PL nEMG for the faster group in the preferred cut compared to the slower group, although this was non-significant. Conclusion: The greater activity of the inside leg PL for the faster group, shown by the large effect, could have aided foot movement during the change-of-direction step. Nevertheless, ankle muscle activity generally did not distinguish between faster and slower reactive cuts in basketballers.