Jamaludin, Nazatul Izzati
(2022)
The mechanism of dynamic knee valgus and the concurrent validity and reliability during single leg squat in physically active females.
Masters thesis, Universiti Sains Malaysia.
Abstract
Excessive dynamic knee valgus (DKV) or inward movement of the knee during
motions is due to the altered kinematics of hip (i.e., top-down kinetic chain) and ankle
(i.e., bottom-up kinetic chain) joints. Excessive DKV during motions is a major
predictor of lower limb injuries, particularly in females, and can be measured using
single leg squat (SLS) tests. However, its mechanism and kinetic chain during SLS are
unknown. Therefore, the primary goal of the current study was to elucidate the
mechanism of DKV, which include top-down (i.e., influence of hip musculature on
motions at knee joint) and bottom-up kinetic chain (i.e., influence of ankle musculature
on motions at knee joint), among physically active females. The secondary goal is to
examine the validity of 2-Dimensional (2-D) and 3-Dimensional (3-D) motion capture
methods in evaluating knee angle during SLS at two squat depths and the within-and
between-days reliability of these methods. 34 participants went through screening test
and divided into two groups (i.e., normal DKV and excessive DKV group). Then, 3-D
knee kinematics (i.e., joint angle) during SLS test at 45° and 60° of knee flexion were
observed. The same SLS test was repeated to examine within-and between-days
reliability. The motions were captured simultaneously by digital cameras in frontal and
sagittal planes with 3-D infrared cameras to examine the validity between the both
methods in evaluating knee angle. Weight-Bearing Lunges Test was conducted to evaluate their ankle range of motion (ROM). Ankle and Hip Isokinetic Strength was
tested at 180°/s angular velocity in ankle dorsiflexion, plantarflexion, inversion and
eversion and hip flexion, extension, abduction and adduction for both legs. Pearson
correlation was used to examine the relationships between hip, ankle strength and ankle
ROM and knee kinematics during SLS at both angles. Intraclass Correlation Coefficient
(ICC) was used as indicator for within-and between-days reliability test of both groups.
Bland-Altman Plot and Pearson correlation were used to illustrate the validity of 2-D
and 3-D motion capture methods. Normal DKV group shows significant relationships
between dominant hip adduction strength (r=-0.51, p=0.04), non-dominant hip
extension strength (r=-0.56, p=0.02) and knee angle during SLS. Significant
relationship was noticed between non-dominant hip abduction strength and knee angle
during SLS (r=-0.53, p=0.03) in excessive DKV group. Next, there were significant
relationships between dominant ankle angle (r=0.51, p=0.04) and distance (r=-0.53,
p=0.03) with knee angle in normal group, and between non-dominant ankle angle
during 45° knee flexion (r=0.51, p=0.04) and non-dominant ankle angle during 60° knee
flexion (r=0.50, p=0.04) with knee angle in excessive DKV group. Next, both methods
of evaluating knee angle at both squat depths are shown valid for both legs in normal
group. However, the methods are valid only for non-dominant leg during SLS at 60°
knee flexion for excessive DKV group. Thus, both groups demonstrated the influence of
the top-down and bottom-up kinetic chains on knee kinematics during SLS, with
distinct muscle groups being emphasised in each group. Besides, SLS is a valid and
reliable test for 2-D and 3-D methods of studying knee angles at squat depths of 45° and
60° knee flexion for participants with normal and excessive DKV groups.
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