#Participants ACL-injures subjects ACL-injury group will be recruit people with ACL-injuries with grade I-II at least 8 weeks by measuring joint laxity test by stress X-ray with Telos (side to side difference between 3 - 8 mm.) .
Inclusion criteria of ACL-injuries group are: 1) no collateral ligaments and meniscus injuries , 2) no joint pain and knee joint effusion (less than 2 cm. from the opposite side measuring at joint line, 3) no history of previous injuries in other structure of lower extremities that resulted in ligamentous laxity at ankle and hip, 4) no current medical problems such as vestibular system, visual system or neurological condition that can impair their ability to perform a sidestep cutting task, 5) no joint and structural deformity such as flat feet, genu valgus and genu varus, 6) able to complete functional test (Single hop for distance and Triple hop for distance) which the distance is not less than 85% of unaffected side .
Exclusion criteria included 1) knee joint swelling is greater than 2 cm. of unaffected side, 2) joint laxity test by stress X-ray with Telos (side to side difference greater than 8 mm.)
* Instrumentation
1. Three-dimensional motion analysis system (Bioengineering Inc., ITALY)
2. Visual 3D software (C-motion, USA)
3. A force platform with 60x40x10 centimeters in size (Kistler Instrument Corp., USA)
4. Running shoes (Adidas) US Size 7 , 8 , 9, 10
5. Goniometer
6. Vernier caliber
7. Measuring tape
8. Therapeutic tape ; (KinesioTex®)
9. Telos arthrometer GA III/E (Metax GmbH)
10. International Knee Documentation Committee Score (IKDC)
11. Knee Osteoarthritis Outcome Score (KOOS)
* Subject preparation for participants with ACL-injuries Participants will be asked to fill in a questionnaire about age, height, weight and history of injury or musculoskeletal problems. Participants will be informed to make understanding of purposes, methods and advantages of the study. Also, all participants will be asked to sign a consent form. IKDC and KOOD interviews will be conducted.The test including hop test and drop vertical jump will be conducted at Faculty of Medicine Ramathibodi, Mahidol University.
Anthropometric data, navicular drop test, ROM and muscle strength at knee joint will be performed in each participant. Participants will be asked to perform single hop for distance and triple hop on both side of their legs.
Stress X-ray by Telos® Participants will be screened joint laxity by stress x-ray with Telos. Lateral view x-ray will be performed in side lying position with knee flexion between 10 to 20 degrees. Front cushion pad will be applied on distal femur and distal tibia. Pressure load will be applied on 6 cm below knee joint line at 15 daN.
Participants with ACL injuries subjects will rest for 10 minute in the quiet room and elastic therapeutic tape will be applied on affected side. Drop vertical jump will be performed follow by running 30 minutes at speed 7 km/hr. Participants will be asked to perform drop vertical jump task again after running.
Drop vertical jump Drop vertical jump landing trails was performed on 31 cm. box . Participants were informed to jump with two hands over head as high as possible and landing on force plate with each foot on separate force plate . Participants were asked to perform the task until reach three successful trials. Successful trial was defined as participants can land on force plate with each foot on separate force plate without further steps.
#Parameters
Knee joint angle and moment at initial contact and weight acceptance phase
1. Flexion - Extension
2. Adduction - Abduction
3. Internal - External rotation
* Statistics All data will be presented in mean ± stand error of mean. All the statistical test will be performed by using the SPSS for window version 17 program. The level of significance for difference between groups will be set at p\< 0.05.
Comparison of 3D joint angles and moments between affected leg and unaffected leg in ACL-injuries group during side step movement will be tested by Paired T test.
