Athletes with a clinical rating of good and poor lumbopelvic stability have different kinematic variables during single leg squat and dip test

Background: Softball pitchers have an eminent propensity for injury due to the high repetition and ballistic nature of the pitch. As such, trunk pathomechanics during pitching have been associated with upper extremity pain. The single leg squat (SLS) is a simple diagnostic tool used to examine LPHC and trunk stability. Research shows a lack of LPHC stability is often associated with altered pitching mechanics consequently increasing pain and injury susceptibility. Hypothesis/Purpose: The purpose of this study was to examine the relationship between trunk compensatory kinematics during the SLS and kinematics during foot contact of the windmill pitch. The authors hypothesized there would be a relationship between SLS compensations and pitch kinematics previously associated with injury. In using a simple clinical assessment such as the SLS, athletes, coaches, parents, and clinicians can identify potential risk factors that may predispose the athlete to injurious movement patterns. Methods: Fifty-five youth and high school softball pitchers (12.6±2.2 years, 160.0±11.0 cm, 60.8±15.5 kg) were recruited to participate. Kinematic data were collected at 100Hz using an electromagnetic tracking device. Participants were asked to complete a SLS on their stride leg (contralateral to their throwing arm), then throw 3 fastballs at maximal effort. Values of trunk flexion, trunk lateral flexion, and trunk rotation at peak depth of the SLS were used as the dependent variables in three separate backward elimination regression analyses. Independent variables examined at foot contact of the pitch included: trunk flexion, trunk lateral flexion, trunk rotation, center of mass, stride length, and stride knee valgus. Results: The SLS trunk rotation regression, F(1,56) = 4.980, p = .030, revealed trunk flexion significantly predicted SLS trunk rotation (SE = .068, t = 2.232, p = .030) and explained approximately 7% of variance (Adj. R2 = .066). The SLS trunk flexion regression, F(1,56) = 5.755, p = .020, revealed stride knee valgus significantly predicted SLS trunk flexion (SE = .256, t = 2.399, p = .020) and explained approximately 8% of variance (Adj. R2 = .078). Conclusion/Significance: Additional trunk rotation and trunk flexion at peak depth of the SLS indicate increased knee valgus and trunk flexion at foot contact of the pitch, both of which suggest poor LPHC stability, may increase the potential for injury. Athletes, coaches and clinicians should acknowledge the risk of poor LPHC in softball pitching and implement exercises to improve LPHC stability in effort to decrease pitching pathomechanics and associated pain.

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Hip and ankle strength and range of motion in female soccer players with dynamic knee valgus

Isokinetics and Exercise Science ◽

10.3233/ies-200260 ◽

2021 ◽

pp. 1-6

Author(s):

Young Jin Jo ◽

Young Kyun Kim

Keyword(s):

Range Of Motion ◽

Female Athletes ◽

External Rotation ◽

Preventive Measure ◽

Control Group ◽

Knee Valgus ◽

Strength Ratio ◽

Flexion Extension ◽

Hip Abduction ◽

Single Leg Squat

BACKGROUND: Dynamic knee valgus (DKV) is a known risk factor for acute and chronic knee injuries and is more frequently diagnosed in females. A real-time single-leg squat test (SLST) could screen for DKV to prevent injuries. OBJECTIVE: To compare the differences in lower extremity strength and range of motion (ROM) in female soccer athletes with and without DKV during an SLST. METHODS: Eighteen subjects with DKV (DKV group) and 18 subjects without DKV (control group) during a single-leg squat were included. Hip strength (flexion, extension, abduction, adduction, internal rotation, and external rotation) was measured with a hand-held dynamometer. Hip ROM (internal and external rotation), and ankle ROM (dorsiflexion with the knee flexed and extended) were measured. Independent t-test was used to compare the averages of the groups. RESULTS: There were significant differences in hip abduction to adduction strength ratio (DKV: 1.48 ± 0.3, control: 1.22 ± 0.26, p< 0.01) and ankle dorsiflexion with knee flexed (DKV: 17.22 ± 6.82, control: 21.22 ± 4.55, p< 0.05) and extended (DKV: 10.14 ± 4.23, control: 14.75 ± 3.40, p< 0.001) between the groups. CONCLUSION: The hip abduction to adduction strength ratio and gastrocnemius and soleus flexibility may be associated factors in dynamic knee valgus and therefore should be assessed and treated, if indicated, as a possible preventive measure in female athletes with this variation.

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