Persistent biomechanical deficits observed in professional soccer players with a history of hamstring injury during a reactive functional test

Objectives:
The aim of the study was to estimate hip extensor muscle stretching capacity as
a function of previous hamstring injury during a for-purpose, standardised test
permitting unrestricted full-body movement, including hamstrings, adductors and
gluteal muscle length evaluated using a musculoskeletal modelling approach.

Method:
Twenty-seven professional footballers, distributed in two groups (control or
previously injured), performed a reactive functional test to one of four
targets from a standing start and performed a knee and plantar extension on
target. Joint kinematics served as input data of a musculoskeletal model, and
joint angles and hip extensor muscle lengths were calculated

Results:
A reduced range of motion of anterior pelvis, hip and knee joints at the peak
of BFlh length was observed associated with a lesser ability to actively stretch
the posterior muscle chain. Additionally, a shorter time-to-peak length in was
found in previously-injured compared to non-previously-injured players during
the functional test.

Conclusion: Persistent
biomechanical deficits can be observed in athletes with HSI even after
undergoing rehabilitation and
returning to a full competition and training schedule. Musculoskeletal
modelling allowed the analysis of musculoskeletal function in greater detail
than using kinematics assessment alone. These findings contribute to assist
medical practitioners, sport physicians and physiotherapists to design
efficient programmes for diagnosis and management of HSI injury.