Lower Limb (Patho-)Mechanical Joint Contact Forces and Intrinsic Foot Muscle Properties in Subjects With Lateral Ankle Sprain and Chronic Ankle Instability

Lower limb joint angles

Time Frame: 5 minutes after the end of the intervention

Part of "Kinematic data" Unit of measurement: Degrees Measurement tools: Vicon software (data acquisition) + Matlab routine (data processing) Method: Joint angles will be measured based on the position of passive markers placed on participants' anatomical landmarks all over the lower limbs. The position of those markers will be tracked by 10 infrared high-speed cameras that surround the walkway (sampled at 100Hz - type T-10, 1 megapixel, captures 10-bit grayscale using 1120 \* 896 pixels, Vicon Motion System Ltd, Oxford, Metrics, UK). The angular positions of the multiple joints that constitute the lower limb (hip, knee, ankle, chopart, lisfranc and metatarsophalangeal) will be assessed during running, side-cutting and crossing over a small obstacle in the gait laboratory.

Lower limb joint angular velocities

Time Frame: 5 minutes after the end of the intervention

Part of "Kinematic data" Unit of measurement: Degrees/second Measurement tool: Vicon software + Matlab routine Method: Joint angular velocities are also assessed based on reflexive markers placed on anatomical landmarks. This outcome evaluates the rate of change of a certain joint angle over time. Joint angular velocities will be assessed during running, side-cutting and crossing over a small obstacle in the gait laboratory.

Joint powers

Time Frame: 5 minutes after the end of the intervention

Part of "Kinetic data" Unit of measurement: Watt Measurement tools: Pressure plate + Vicon software + Matlab routine Methods: Joint moments will be determined by coupling kinematic data (joint position and velocities) with plantar pressure data from a specially designed pressure plate (sampled at 200Hz, Footscan, dimension 0.5m x 0.4m, 4096 sensors, 2.8 sensors/cm², RsScan International, Olen, Belgium) embedded in the middle of the runway and placed on top of a force plate (sampled at 1000Hz, Advanced Mechanical Technology Inc., Watertown, MA, USA). Kinetic data will be assessed while running, side-cutting and crossing over a small obstacle in the gait laboratory.

Intrinsic foot muscle area

Time Frame: Baseline

Unit of measurement: cm² (cm square) Methods: The area of five intrinsic foot muscles (abductor hallucis, flexor digitorum brevis, flexor hallucis, quadratus plantae and abductor digiti minimi) will be measured on images obtained using ultrasonography. To obtain those images, the investigators will scan the muscles in a transversal view.

Joint moments

Time Frame: 5 minutes after the end of the intervention

Part of "Kinetic data" Unit of measurement: Newton-meter Measurement tools: Pressure plate + Force plate + Vicon software + Matlab routine Methods: Joint moments will be determined by coupling kinematic data (joint position and velocities) with plantar pressure data from a specially designed pressure plate (sampled at 200Hz, Footscan, dimension 0.5m x 0.4m, 4096 sensors, 2.8 sensors/cm², RsScan International, Olen, Belgium) embedded in the middle of the runway and placed on top of a force plate (sampled at 1000Hz, Advanced Mechanical Technology Inc., Watertown, MA, USA). Kinetic data will be assessed while running, side-cutting and crossing over a small obstacle in the gait laboratory.

Intrinsic foot muscle thickness

Time Frame: Baseline

Unit of measurement: cm Methods: The thickness of five intrinsic foot muscles (abductor hallucis, flexor digitorum brevis, flexor hallucis, quadratus plantae and abductor digiti minimi) will be measured on images obtained using ultrasonography. To obtain those images, the investigators will scan the muscles in a longitudinal view.