This study evaluates the effect of different surfaces on the load experienced by the knee when landing from a single leg hop. A sand, pliable grass and firm (hard floor) surface will be compared when hopping from a 30 cm height. Each subject will complete 5 hops on each surface in a random order. The muscle activity in selected muscles of the lower limb will also be investigated to see how this differs in the landing leg, when landing on the different surfaces.

The aim of this study is twofold: 1) To investigate the effect of sand on landing kinematics and kinetics at the knee joint when performing a single leg jump landing task (dominant leg), comparing sand with a firm surface and pliable grass control. 2) To investigate the sEMG activity of the hamstring, quadriceps and gastrocnemius muscles of the dominant leg during the jump landing task on these different surfaces (from take off through to terminal knee flexion at the end of the landing phase).

Inclusion Criteria:

• Female
• Participate in a minimum of 3 hours sporting activity per week.
• Provided Informed Consent
• Must be over 16 years of age (16-45 years)
• No exclusion criteria

Exclusion Criteria:

• Not willing to provide informed consent
• Pregnant
• History of ACL injury or other knee pathology
• Significant lower limb pathology
• Previous lower limb fracture or surgery
• Lower Limb injury in last 3 months.
• Male

most be female to be eligible for the study