Lower Limb and Trunk Biomechanics After Fatigue in Competitive Female Irish Dancers.
J Athl Train. 2017 Apr 24;:
Authors: Wild CY, Grealish A, Hopper D
CONTEXT: Because of the increasing popularity of participation in Irish dance, the incidence of lower limb injuries is high among this competitive population.
OBJECTIVE: To investigate the effects of fatigue on the peak lower limb and trunk angles as well as the peak lower limb joint forces and moments of competitive female Irish dancers during the performance of a dance-specific single-limb landing.
DESIGN: Cross-sectional study.
PATIENTS OR OTHER PARTICIPANTS: Fourteen healthy, female, competitive Irish dancers (age = 19.4 ± 3.7 years, height = 165.3 ± 5.9 cm, mass = 57.9 ± 8.2 kg).
INTERVENTION(S): Participants performed an Irish dance-specific leap before and after a dance-specific fatigue protocol. During each landing movement, 3-dimensional lower limb kinematics (250 Hz) and ground reaction forces (1000 Hz) were collected. Paired t tests were performed to determine the differences (P ≤ .05) in lower limb and trunk biomechanics prefatigue and postfatigue.
MAIN OUTCOME MEASURE(S): Peak lower limb and trunk angles as well as peak lower limb joint reaction forces and external moments.
RESULTS: Compared with the prefatigue trials, dancers landed with reduced ankle plantar flexion (P = .003) and hip external rotation (P = .007) and increased hip-adduction alignment (P = .034) postfatigue. Dancers displayed greater anterior shear (P = .003) and compressive (P = .024) forces at the ankle and greater external knee-flexion moments (P = .024) during the postfatigue compared with the prefatigue landing trials.
CONCLUSIONS: When fatigued, dancers displayed a decline in landing performance in terms of aesthetics as well as increased ankle- and knee-joint loading, potentially exposing them to a greater risk of injuries when fatigued.
PMID: 28437130 [PubMed - as supplied by publisher]
Acute Ankle Sprain in a Mouse Model: Changes in Knee-Joint Space.
J Athl Train. 2017 Apr 24;:
Authors: Hubbard-Turner T, Wikstrom EA, Guderian S, Turner MJ
CONTEXT: Ankle sprains remain the most common orthopaedic injury. Conducting long-term studies in humans is difficult and costly, so the long-term consequences of an ankle sprain are not entirely known.
OBJECTIVE: To measure knee-joint space after a single surgically induced ankle sprain in mice.
DESIGN: Randomized controlled trial.
SETTING: University research laboratory.
PATIENTS OR OTHER PARTICIPANTS: Thirty male mice (CBA/2J) were randomly placed into 1 of 3 surgical groups: the transected calcaneofibular ligament (CFL) group, the transected anterior talofibular ligament/CFL group, and a sham treatment group. The right ankle was operated on in all mice.
MAIN OUTCOME MEASURE(S): Three days after surgery, all of the mice were individually housed in cages containing a solid-surface running wheel, and daily running wheel measurements were recorded. Before surgery and every 6 weeks after surgery, a diagnostic ultrasound was used to measure medial and lateral knee-joint space in both hind limbs.
RESULTS: Right medial (P = .003), right lateral (P = .002), left medial (P = .03), and left lateral (P = .002) knee-joint spaces decreased across the life span. The mice in the anterior talofibular ligament/CFL group had decreased right medial (P = .004) joint space compared with the sham and CFL groups starting at 24 weeks of age and continuing throughout the life span. No differences occurred in contralateral knee-joint degeneration among any of the groups.
CONCLUSIONS: Based on current data, mice that sustained a surgically induced severe ankle sprain developed greater joint degeneration in the ipsilateral knee. Knee degeneration could result from accommodation to the laxity of the ankle or biomechanical alterations secondary to ankle instability. A single surgically induced ankle sprain could significantly affect knee-joint function.
PMID: 28437129 [PubMed - as supplied by publisher]