A study of 50 softball athletes found no significant difference between players classified as stable or unstable in the speed of their body segments during an overhead throw or in the sequence those segments used. The authors interpreted the result as showing no apparent relationship between SLS-defined lumbopelvic-hip complex stability and the measured throwing motion in this sample.
The sample included 18 NCAA Division I collegiate players, 17 high-school players and 15 youth players. The researchers asked whether the sequence of body-segment movement during a throw and the maximum speeds of those segments differed according to lumbopelvic-hip complex, or LPHC, instability status.
The test behind the comparison
They expected athletes with LPHC instability to show improper segmental sequencing and lower maximum segmental velocities.
The stability label came from a single-leg squat, abbreviated SLS. An athlete was classified as unstable when knee valgus exceeded 15 degrees at 45 degrees of knee flexion during the descending phase on one or both legs.
Each athlete performed three maximal-effort overhead throws to a teammate 60 feet away and then completed an SLS on each leg. Electromagnetic tracking collected kinematic data at 100 Hz; force-plate data were sampled at 1,000 Hz only to mark stride-foot contact.
The researchers averaged the kinematic data across the three throws and compared the groups with one-way ANOVAs and Bonferroni post-hoc tests. They set the statistical significance threshold in advance at 0.05.
What the comparisons showed
When the athletes were analyzed within their age levels, maximum angular and linear velocities did not differ significantly between stable and unstable groups in college, high-school or youth players. In each comparison, the reported p-value was greater than 0.05.
Segmental sequencing showed the same pattern. Within each age level, the sequence of movement did not differ significantly between the two stability groups, with reported p-values greater than 0.05.
The all-athlete analysis reached the same conclusion: after the age groups were considered together, there were no significant stable-versus-unstable differences in maximum angular or linear velocities or in segmental sequencing. The sequencing comparison had a p-value greater than 0.05.
But the strength of the age-specific comparisons was limited. Reported statistical power was 0.12 for college athletes, 0.10 for high-school athletes and 0.09 for youth athletes, compared with 0.83 for the overall sample.
Limits on the takeaway
The authors also pointed to small age-specific groups, with no more than 12 participants in any stability group, and recruitment from the Auburn/Opelika, Alabama area. Those limitations narrow how confidently the findings can be generalized beyond this sample.
The throwing protocol was brief: athletes made only three throws while rested. The authors noted that this may not capture overuse-related behavior and recommended testing with longer or simulated-game throwing bouts.
What was reported
Auburn University's Institutional Review Board approved the testing, and informed consent or parental assent was obtained before data collection. The authors reported no potential conflict of interest.
Paper data and sources
Original title: Assessment of lumbopelvic–hip complex instability and segmental sequencing amongst softball athletes
Authors: Gilmer G, Washington J, Oliver G
Journal/Repository: International biomechanics
Status: Peer-reviewed
First online: 2026-10-12
DOI: Not available
Original paper · Full text