Hop Testing should not be performed until Zero or Trace Effusion is seen based on established grading scale below.3,8
- Zero: No wave produced on downstroke
- Trace: Small wave on medial side with downstroke that does not fill the sulcus
- 1+: Larger bulge on medial side with downstroke that fills the sulcus
- 2+: Effusion spontaneously returns to the medial side after upstroke (no downstroke necessary) and fills the sulcus
- 3+: So much fluid that it is not possible to move the effusion out of the medial aspect of the knee11
Range of Motion should be full compared to contralateral limb.3,8
Quadriceps Index (QI):
Hop Testing for return to sport should not be performed until quadriceps strength is 90% or greater compared to the uninvolved if using for return to sport criteria.12 Testing should not be performed in any circumstance until the QI is at least 70% of uninvolved.
Optimal testing conditions are to use a biodex, positioned isometrically at 60 degrees for ACL injuries.12 Patella femoral injuries and other knee testing can also be performed at 60 degrees or 90 degress with a history of patellar subluxation/dislocation. In the presence of a PCL injury, testing should be performed at 30 degrees to minimize strain of PCL graft. In the event of a combined ACL/PCL reconstruction, testing should be performed at 45 degrees to minimize strain on both grafts.
In the absence of a biodex or hand held dynamometer, a 1 Rep Maximum (RM), using a leg extension machine, can be calculated using repetitions of a selected weight. The formula has been shown to be accurate in estimating 1 RM squats in high-school power lifters.13 The attached spreadsheet can be used to fill in the repetitions and repetition weight with a Quadriceps Index calculated automatically.
1 Rep Maximum = 159.9 + (.103 x Reps x Repetition Weight) + (-11.552 x reps).13
Functional Outcome Surveys:
KOS: ADLs and Sports subscales should be completed after hop testing. A score of 90% or greater is required to allow return to sport.12
- The hop test setup is 6m in length by 15 cm in width.
- A mark should be made at each 1 meter interval for ease of measurement during testing.
- All testers will need a measuring tape to record distance and a stop watch to record time for the 6 meter hop.
- Begin with the uninvolved limb first
- There should be 1 trial tests for each limb followed by 2 true tests for each limb
- For example, if the right limb is the uninvolved limb:
- Right trial, Right test, Right test
- Left trial, Left test, Left test
- This should be repeated for each individual hop test as you go.
- For example, if the right limb is the uninvolved limb:
- The order of hop tests should be as follows:
- Single Hop: Pt. hops on one foot as far as possible; this is measured for distance
- Cross-over Hop: Pt. performs 3 forward hops, but each time must cross over the 15cm width of the testing area.
- Pt able to select whether they begin by hopping medially or laterally, but must remain consistent throughout trials and between sides.
- Triple Hop: Pt hops forward three times consecutively on one limb; this is measured for distance
- Timed Hop: Pt hops forward as quickly as they can on one foot for the entire 6 meter distance.
- The diagram below shows how each hop should be performed
- Hops are measured by starting with the great toe behind the 0cm mark and by marking the location of the heel at the landing point.
- Subjects are allowed a rest break between hops trials if necessary (no greater than 30 sec) and between each type of hop test (up to 2 minutes)
The hop test must be repeated if the following occur:
- For distance hops, the landing is maintained for less than 2 seconds.
- An unsuccessful hop is classified by:
- Touching down the contralateral limb
- Touching down of either upper extremity
- Loss of balance
- Additional hop on landing
- Using any other object to maintain balance
- An average of the two true tests for each limb should be calculated to determine the ultimate score.
- The average scores for each limb on each hop test should be compared to determine how the involved limb compares to the uninvolved.
- For the distance hops: (involved average score/uninvolved average score) x100%
- For the timed hop: (uninvolved average score/involved average score)x100%
- Involved side must be greater than or equal to 90% of the uninvolved side for each individual hop test.
- No giving way, increased effusion, or increased pain.
- If a patient has 1 of 4 hop tests that they do not achieve 90% or > they may re-do ONLY 1 test using the same guidelines for application as above.
- Scoring and passing criteria remain the same as the original test
- Ingram JG, Fields SK, Yard EE, et al. Epidemiology of knee injuries among boys and girls in US high school athletics. Am J Sports Med. June 2008;36(6):1116-22.
- Logerstedt D, Grindem H, Lynch A et al. Single-legged hop test as predictors of self-reported knee function after anterior cruciate ligament reconstruction. Presented at AOSSM. July 2012.
- Reid A, Birmingham TB, Stratford PW, et al. Hop testing provides a reliable and valid outcome measure during rehabilitation after anterior cruciate ligament reconstruction. Physical Therapy. March 2007;87(3):337-349.
- Brosky JA, Nitz AJ, Malone TR, et al. Intrarater reliability of selected clinical outcome measures following anterior cruciate ligament reconstruction. J Orthop Sports Phys Ther. 1999;29:39–48.
- Kramer JF, Nusca D, Fowler P, Webster-Bogaert S. Test-retest reliability of the one-leg hop test following ACL reconstruction. Clin J Sport Med. 1992;2:240–243.
- Hopper DM, Goh SC, Wentworth LA, et al. Test-retest reliability of knee rating scales and functional hop tests one year following anterior cruciate ligament reconstruction. Physical Therapy in Sport. 2002;3:10–18.
- Hamilton RT, Shultz SJ, Schmitz RJ, et al. Triple-hop distance as a valid predictor of lower limb strength and power. J Athl Train. March 2008;43(2):144-51.
- Fitzgerald GK, Lephart SM, Hwang JH, et al. Hop tests as predictors of dynamic knee stability. J Orthop Sports Phys Ther. 2001;31(10):588-97.
- Sernert N, Kartus J, Kohler K, et al. Analysis of subjective, objective, and functional examination tests after anterior cruciate ligament reconstruction. A follow-up of 527 patients. Knee Surg Sports Traumatol Arthrosc. 1999;7:160-165.
- Risberg MA, Holm I, Tjomsland O, et al. Prospective study of changes in impairments and disabilities after anterior cruciate ligament reconstruction. J Orthop Sports Phys Ther. 1999;29:400-412.
- Sturgill LP, Snyder-Mackler LS, Manal TJ, et al. Interrater Reliability of a Clinical Scale to Assess Knee Joint Effusion. J Orthop Sports Phys Ther 2009;39(12):845-849.
- Adams D, Logerstedt D, Hunter-Giordano A, et al. Current concepts for Anterior Cruciate Ligament Reconstruction: A Criterion-Based Rehabiliation Progression. J Orthop Sports PHys Ther. 2012;42(7):601-614.
- Kravitz L, Akalan C, Nowicki K. Prediction of 1 Reptition Maximum in High-School Power Lifters. Journal of Strength & Conditioning Research. 2003;17(1):167-172.