Core Strength Training Can Alter Neuromuscular and Biomechanical Risk Factors for Anterior Cruciate Ligament Injury

Abstract

Background: Core stability is influential in the incidence of lower extremity injuries, including anterior cruciate ligament (ACL) injuries, but the effects of core strength training on the risk for ACL injury remain unclear. Hypothesis: Core muscle strength training increases the knee flexion angle, hamstring to quadriceps (H:Q) coactivation ratio, and vastus medialis to vastus lateralis (VM:VL) muscle activation ratio, as well as decreases the hip adduction, knee valgus, and tibial internal rotation angles. Study Design: Controlled laboratory study. Methods: A total of 48 male participants were recruited and randomly assigned to either the intervention group (n = 32) or the control group (n = 16). Three-dimensional trunk, hip, knee, and ankle kinematic data and muscle activations of selected trunk and lower extremity muscles were obtained while the participants performed side-step cutting. The core endurance scores were measured before and after training. Two-way analyses of variance were conducted for each dependent variable to determine the effects of 10 weeks of core strength training. Results: The trunk endurance scores in the intervention group significantly increased after training ( P < .05 for all comparisons). The intervention group showed decreased knee valgus ( P = .038) and hip adduction angles ( P = .032) but increased trunk flexion angle ( P = .018), rectus abdominis to erector spinae coactivation ratio ( P = .047), H:Q coactivation ratio ( P = .021), and VM:VL activation ratio ( P = .016). In addition, the knee valgus angle at initial contact was negatively correlated with the VM:VL activation ratio in the precontact phase ( R2 = 0.188; P < .001) but was positively correlated with the hip adduction angle ( R2 = 0.120; P < .005). No statistically significant differences were observed in the trunk endurance scores, kinematics, and muscle activations for the control group. Conclusion: Core strength training altered the motor control strategies and joint kinematics for the trunk and the lower extremity by increasing the trunk flexion angle, VM:VL activation ratio, and H:Q activation ratio and reducing the knee valgus and hip adduction angles. Clinical Relevance: Training core muscles can modify the biomechanics associated with ACL injuries in a side-step cutting task; thus, core strength training might be considered in ACL injury prevention programs to alter the lower extremity alignment in the frontal plane and muscle activations during sports-related tasks.

The effects of hip- and ankle-focused exercise intervention on dynamic knee valgus: a systematic review

“…Additionally, thirteen other potential papers were identified when manually checking the reference lists of the included articles. Only eight fulfilled the inclusion criteria ( Sheerin, Hume & Whatman, 2012 ; Baldon et al, 2014 ; Czasche et al, 2017 ; Araújo et al, 2017 ; McCurdy et al, 2012 ; Jeong, Choi & Shin, 2020 ; Thompson-Kolesar et al, 2017 ; Saad et al, 2018 ). Therefore, a total of ten studies were included in the final review.…”

“…Nevertheless, this findings were only limited to females with PFPS (Baldon et al, 2014). Jeong, Choi & Shin (2020) reported that the intervention group showed reduced knee valgus during side-step cutting task following ten weeks of core strength training. This study involved 48 male participants who were assigned randomly to either the intervention or control group.…”

“…The results corroborate the findings of Willson, Ireland & Davis (2006), who discovered that participants with greater isometric core strength had reduced knee valgus angle during SLS. Jeong, Choi & Shin (2020) concluded that core strengthening, which involves top-down kinetic chain exercises, may assist male athletes in avoiding knee valgus alignment during side-step cutting. Saad et al (2018) reported that eight weeks of hip and quadriceps exercises (i.e., topdown kinetic chain) significantly reduced knee valgus angle during step tasks.…”

“…Czasche et al (2017),Jeong, Choi & Shin (2020) & McCurdy et al (2012 did not mention any screening procedure used to evaluate excessive DKV.Moreover, Baldon et al (2014) andSaad et al (2018) did not specify any screening procedure to evaluate excessive DKV because they implied the presence of knee valgus based on the diagnosis of PFPS. However, other five studies, namelyBarendrecht et al (2011); Bell et al (2013);Araújo et al (2017);Sheerin, Hume & Whatman (2012);Thompson-Kolesar et al (2017), screened the participants for excessive DKV through various types of test.Barendrecht et al (2011) measured knee valgus from the drop-jump test by evaluating the knee minimum distance values (i.e., less than 49.96% showed the presence of knee valgus) using 2-D analysis.Meanwhile, Bell et al (2013) visually confirm the presence of knee valgus during double-legged squat whereas,Araújo et al (2017) screened DKV during 18-cm step-down task Sheerin, Hume & Whatman (2012).…”

Are Core Stability Tests Related to Single Leg Squat Performance in Active Females?

“…A growing body of research suggests [ 11 , 12 ] that core stability (CS) deficits can have a significant impact on lower limb function [ 13 ]. Based on this idea, poor CS is currently considered a crucial factor in the development of lower extremity injuries, which are usually solely attributed to lower limb malfunction [ 14 , 15 ].…”