The purpose of this study is to evaluate the effects of experimental knee pain on the muscle strength gain after 8 weeks of strengthening exercises for the quadriceps. It is hypothesized that experimental knee pain will reduce the muscle strength gain following strengthening exercises in healthy volunteers.

Inclusion Criteria:

• aged between 20 to 35 years
• healthy
• untrained (non-regular exercise participation [i.e. < 1 day/week])

Exclusion Criteria:

• symptomatic musculoskeletal diseases
• history of traumatic injuries to muscles, tendons or joints of the lower extremity
• knee joint pain within a month prior to enrollment