Objectives The purpose of this study was to investigate the effect of transverse plane foot position on lower limb kinematics during a single leg squat. Methods This was a cross-sectional study conducted among highly-trained male athletes. Only participants who showed normal knee valgus during a drop landing screening test were recruited. Twelve junior athletes performed single leg squats while maintaining a knee flexion angle of 60°. The squats were executed in three foot positions: neutral (0°), adduction (−10°), and abduction (+10°). Three-dimensional motion analysis was used to capture the lower extremity kinematics of the participants’ preferred limb. The hip and knee kinematics in the sagittal, frontal, and transverse planes during squatting were compared across the three foot positions using one-way ANOVA. Results The participants showed a normal range of dynamic knee valgus (5.3°±1.6). No statistically significant differences were observed in hip flexion (p = 0.322), adduction (p = 0.834), or internal rotation (p = 0.967) across different foot positions. Similarly, no statistically significant differences were observed in knee flexion (p = 0.489), adduction (p = 0.822), or internal rotation (p = 0.971) across different foot positions. Conclusion Small changes in transverse plane foot position do not affect lower extremity kinematics during single leg squat in highly trained adolescent males with normal dynamic knee valgus. Our findings may provide guidance on safer techniques for landing, pivoting, and cutting during training and game situations.

This study was conducted to evaluate the relationships between core strength, dynamic balance and knee kinematics during single leg squat. Core strength helps to improve dynamic balance and muscle coordination between lower and upper extremities, as well as reduce injury risks and muscular strength imbalance. Dynamic balance is the ability to maintain a stable position during dynamic tasks and can be used as a predictor of injury risk factors. Thirty-two statelevel male junior athletes with a normal range of dynamic knee valgus were recruited. The participants went through a series of tests that included Modified Plank Test, Star Excursion Balance Test (SEBT) and Single Leg Squat (SLS) test. Two-dimensional knee frontal plane projection angle (FPPA) during SLS was evaluated at a 60° knee flexion. There was a statistically significant correlation between distance reached in anteromedial direction and knee FPPA during SLS in the non-dominant leg (r = 0.374, p = 0.035). There was no significant correlation between duration of plank and knee FPPA during SLS in both dominant and non-dominant legs. The outcomes from this study are important to prevent lower limb injuries in male junior athletes. ABSTRAKKajian ini telah dijalankan untuk menilai hubungan antara kekuatan teras, keseimbangan dinamik serta kinematik lutut semasa mencangkung dengan sebelah kaki. Kekuatan teras membantu untuk memperbaiki keseimbangan dinamik dan koordinasi otot antara bahagian atas dan bawah anggota badan, di samping mengurangkan risiko kecederaan dan ketidakseimbangan kekuatan otot. Keseimbangan dinamik ialah kebolehan untuk mengekalkan posisi yang stabil semasa tugas dinamik dan boleh digunakan sebagai satu peramal faktor risiko kecederaan. Tiga puluh dua atlet junior lelaki peringkat negeri yang mempunyai lutut valgus dinamik dalam anggaran normal, telah direkrut. Peserta menjalani satu siri ujian yang merangkumi Ujian Plank Diubahsuai, Ujian Keseimbangan Pergerakan Bintang (SEBT) dan ujian Mencangkung Sebelah Kaki (SLS). Sudut unjuran lutut dua dimensi pada satah depan (FPPA) semasa SLS telah dinilai pada lutut bengkok bersudut 60°. Terdapat korelasi yang signifikan secara statistiknya antara jarak yang dicapai dalam arah anteromedial dan FPPA lutut semasa SLS pada kaki tidak dominan (r = 0.374, p = 0.035). Tiada korelasi yang signifikan antara tempoh plank dan FPPA lutut semasa SLS pada kedua-dua kaki dominan dan tidak dominan. Hasil daripada kajian ini adalah penting untuk mencegah kecederaan anggota bawah badan dalam kalangan atlet junior lelaki.Kata kunci: Atlet muda; biomekanik; lutut valgus dinamik; rantaian kinetik atas bawah

Background: Those with increased dynamic knee valgus are vulnerable to increased risk of non-contact knee injuries. However, studies on the top down kinetic chain of lower limb mechanics during dynamic motions such as single leg squat (SLS) among trained males were scarce. Objective: The objective of the study was to evaluate the relationship between isokinetic hip and knee strength and frontal plane projection angle (FPPA) of the knee joint during SLS. Methods: Thirty-two male junior athletes (twelve cyclists, ten runners and ten squash players) were screened for excessive dynamic knee valgus (DKV) prior to participation. Only those within the normal value of DKV were included. Their hip and knee isokinetic strength in sagittal plane were evaluated at 60º/s of angular velocity for both legs using dynamometer. Two dimensional knee FPPA was evaluated during SLS at 60º of knee flexion. Pearson correlation was evaluated between knee FPPA during SLS and isokinetic leg strength. Results: Correlations between knee FPPA and hip and knee isokinetic strength were not statistically significant except between knee flexion peak torque/body weight (r =-0.35, p = 0.05) and hamstring to quadriceps ratio (r =-0.39, p = 0.03) of non-dominant leg. Conclusions: Isokinetic hip and knee strength and knee FPPA during SLS was correlated only for non-dominant leg during SLS among male junior athletes. DKV during SLS may be reduced through strengthening the muscles around hip and knee joints.