Coupled Gluteus Maximus and Gluteus Medius Recruitment Patterns Modulate Hip Adduction Variability During Single-Limb Step-Downs: A Cross-Sectional Study

Association Between Lumbopelvic Stability During a Single-Legged Step Down and Elbow-Varus Torque During Baseball Pitching

CONTEXT

During a baseball pitch, energy is transferred from the lower extremities through the lumbopelvic junction to the upper extremity. Reduced lumbopelvic stability has been associated with elbow injuries, but the mechanisms are unclear.

OBJECTIVE

To characterize the predictive ability of lumbopelvic stability on elbow-varus torque during a baseball pitch.

DESIGN

Cross-sectional study.

SETTING

Facilities at National Collegiate Athletic Association Division I universities.

PATIENTS OR OTHER PARTICIPANTS

A total of 44 National Collegiate Athletic Association Division I baseball players (age = 19.6 ± 1.3 years, height = 190 ± 10 cm, mass = 90.1 ± 6.3 kg).

MAIN OUTCOME MEASURE(S)

Pitchers completed a warm-up and then threw 10 fastballs from a mound to a catcher. During the pitches, elbow-varus torque was recorded using an inertial measurement unit, and ball velocity was recorded using a radar gun. Participants also completed a single-legged step-down (SLSD) task with and without a cognitive Stroop, and triplanar pelvic and trunk kinematics were recorded using inertial measurement units. Statistical analysis consisted of a cluster analysis, principal components analysis, and a multivariate logistic regression model.

RESULTS

Cluster analysis identified 2 clusters: low torque-high velocity and high torque-low velocity. The principal components analysis identified 4 patterns of variability (principal components) during the SLSD: (1) sagittal plane, (2) transverse plane, (3) frontal-plane trail leg, and (4) frontal-plane lead leg. Logistic regression models indicated increased transverse-plane trunk (odds ratio = 2.9; 95% CI = 1.1, 8.0; P = .04) and increased pelvis motion (odds ratio = 2.5; 95% CI = 1.1, 6.0; P = .03) predicted higher odds of belonging to the high torque-low velocity cluster.

CONCLUSIONS

Lumbopelvic movement assessed during the SLSD can identify deficits that relate to high elbow torque-low ball velocity during the baseball pitch. Specifically, higher transverse-plane pelvis and trunk motion were independently associated with pitchers in the high torque-low velocity cluster. Our assessment of trunk and pelvis motion during an SLSD provides a method for coaches and clinicians to identify a potential risk factor related to increased elbow-varus torque and decreased ball velocity.

Role of gluteus maximus and medius activation in the lower limb biomechanical control during functional single-leg Tasks: A systematic review

OBJECTIVES

Single-leg (SL) tasks are included as assessment and intervention strategies in several dysfunctions due to the inherent motor control requirement. The recruitment of gluteus maximus (GMAX) and medius (GMED) muscles is essential for proper biomechanical control of the knee and hip joints. The study aims to identify the role of gluteal activation in the biomechanical control of the lower limb during SL tasks.

METHODS

This is a systematic review with searches performed in Pubmed, CINAHL, MEDLINE, Web of Science, and Sportdiscus databases. Cross-sectional studies carried out with asymptomatic individuals were selected, containing hip and knee kinematic and kinetic outcomes assessed through 3D or 2D movement analysis and EMG activity of GMED and GMAX muscles. Two independent reviewers performed the procedures to select the studies, determine the methodological quality and extract the data.

RESULTS

The initial search resulted in 391 studies, and after the assessment procedures, 11 studies were included. Lower GMAX activation was associated with greater hip internal rotation (HIR) excursion and greater HIR moment, and lower GMED activation was associated with greater hip adduction (HAD)/knee abduction (KAB) excursions and greater KAB moment during single-leg squat (SLS).

CONCLUSIONS

The SL tasks showed a relevant association between the gluteal EMG and other biomechanical outcomes, mainly the SLS task. Interpretation must be cautious, as most studies present high and moderate methodological quality, especially on kinetic data.

Electromyography (EMG) Analysis of Multi-Regional Lower Extremity and Trunk Musculature During Sidelying Hip Abduction With Frontal Plane Stabilization

Sidelying hip abduction (SHA) is a common exercise utilized in rehabilitation to strengthen the gluteus medius (GMed). Alterations in the exercise can produce different patterns of muscular activity. No studies have examined the effect of mechanical pelvic stabilization during SHA. This study enrolled 19 participants (male = 11, female = 8) who performed the same SHA exercise under two randomized conditions: standard and with a mechanical block to prevent frontal-plane movement. Electromyographic amplitudes during exercise were obtained through surface electrodes and compared against maximum voluntary isometric contraction (MVIC) testing: GMed, gluteus maximus, biceps femoris, tensor fascia latae, quadratus lumborum, and vastus lateralis. While no significant differences were found in GMed activity during SHA with or without pelvic stabilization, reduced concomitant activation of other musculature was observed, potentially producing a more isolated exercise for the GMed with less compensatory activity.