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Does the one-leg rise test reflect quadriceps strength in individuals following anterior cruciate ligament reconstruction?

Review written by Dr Christina Le info

Key Points

  1. The one-leg rise test could be an affordable, accessible way of measuring quadriceps strength.
  2. Quadriceps strength (as measured by isometric testing) attenuates with a greater number of one-leg rises achieved.
  3. Performance on the one-leg rise test may be influenced by other non-strength factors (e.g. intrinsic motivation).

BACKGROUND & OBJECTIVE

There is an abundance of research linking quadriceps strength to patient-reported outcomes (1), re-injury risk (2), and developing knee osteoarthritis (3) following an ACL reconstruction (ACLR). Unsurprisingly, guiding patients on how to regain their quads strength is a key pillar of ACLR rehabilitation.

In an ideal world, patients regularly undergo testing with an isokinetic dynamometer, the gold standard for measuring quadriceps strength. As many clinicians do not have access to an isokinetic dynamometer, they may choose to measure quads strength using one-repetition maximum tests on a knee extension machine, hand-held dynamometers, or hop tests.

However, these alternatives also have limitations. Knee extension machines and hand-held dynamometers come with a price tag and hop tests can be influenced by other non-strength factors (e.g. fear of movement). An accessible, inexpensive way to measure quads strength could be the one-leg rise test.

This cross-sectional study examined the validity of the one-leg rise test as a quadriceps strength measure compared to isokinetic dynamometry in individuals post-ACLR.

Quadriceps strength is linked to patient-reported outcomes, re-injury risk, and developing knee osteoarthritis following an ACL reconstruction.
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The one-leg rise test is a good addition to your testing battery.

METHODS

This study evaluated the first 50 female and 50 male participants in the Supervised exercise-therapy and Patient Education Rehabilitation (SUPER-Knee) trial. Participants were included if they were 9-36 months post-ACLR, 18-40 years old at the time of surgery, not undergoing physiotherapy for their knee, and still had a “symptomatic knee”. A symptomatic knee was defined as having a score below 80/100 on the Knee injury and Osteoarthritis Outcome Score-4 (KOOS⁴; mean score of the pain, symptoms, function in sports/recreation, and quality of life subscales).

To perform the one-leg rise test (4) participants sat on the edge of a plinth. The height of the plinth was adjusted so that angle of the test knee was 90°. Participants held their arms across their chest and their non-test leg off the ground. They were instructed to “rise to standing and squat back down until touching the plinth lightly” as many times as possible. A metronome was set to 45bpm (one beat up, one beat down) to ensure participants were performing one-leg rises at a consistent tempo. See the video for a demonstration of the test.

ONE-LEG RISE TEST https://youtu.be/_s6-Ldgms6I

The test stopped when participants could no longer continue doing one-leg rises or after three warnings for test protocol violations (e.g. touching the ground with the non-test leg, losing pace with the metronome, uncontrolled landing on the plinth). The number of one-leg rises was recorded and participants were asked what stopped them from continuing (e.g. fatigue, balance). A 3-minute rest was provided between testing the left (always tested first) and right side.

Quadriceps strength was also measured isometrically at 60° knee flexion using an isokinetic dynamometer. Participants performed 3 max effort trials on each leg with a 60-second rest between trials. Knee pain during the one-leg rise and isometric quads strength tests was assessed on a 100mm visual analog scale (0=no pain, 100=extreme pain).

RESULTS

The mean (standard deviation, SD) age of the 100 participants was 30 (6) years old and median (interquartile range, IQR) time since surgery was 31 (24-35) months. The mean (SD) KOOS₄ score was 64.1 (12.5) out of 100.

On the one-leg rise test, the participants had median (IQR) scores of 13 (9-20) on the ACLR limb side and 17 (11-24) on their contralateral limb for a mean (SD) limb symmetry index of 85% (36%). On the isometric quadriceps strength test, the mean peak torque (SD) was 2.09 (0.53) Nm/kg on the ACLR limb and 2.33 (0.58) Nm/kg on the contralateral limb for a mean (SD) limb symmetry of 90% (12%). Minimal pain (median 10/100) was reported for either test.

A non-linear relationship was found between one-leg rise performance and isometric quads strength where the rate of increased quads strength attenuated at higher scores on the one-leg rise test (see Figure 1). This relationship was observed for both the ACLR and contralateral limbs.

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LIMITATIONS

The authors of this paper note that inter- and intra-rater reliability of the one-leg test was not formally measured but sufficient training and biannual fidelity checks were incorporated into the study protocol to minimize variability between assessors. Additionally, other factors can impact performance on the one-leg rise test, such as balance, strength of other muscle groups (e.g., glutes), and intrinsic motivation, that were not included in the data analysis.

Another limitation is the comparison of the one-leg rise test to an isometric quadriceps strength measurement. Comparing to the true gold standard of isokinetic quadriceps strength may have been more relevant, especially considering the one-leg rise test intends to be a surrogate measure of quadriceps strength through a defined range of motion.

CLINICAL IMPLICATIONS

When measuring quadriceps strength after an ACL injury or surgery, the one-leg rise test could be an affordable alternative to an isokinetic strength test. The main advantage of the one-leg rise test is that it requires little equipment: an adjustable plinth, a goniometer, and a metronome. Most rehabilitation settings are likely to have these pieces of equipment and many free metronome apps are available to download for your smartphone.

However, we must be aware of the limitations of the one-leg rise test. According to these study findings, the relationship between quadriceps strength and one-leg rise performance begins to attenuate with larger number of one-leg rises that can be performed. That is, patients with “higher” scores may achieve these numbers due to other factors (e.g. intrinsic motivation).

Overall, the one-leg rise test is a good addition to your testing battery, but you should still assess quadriceps (and other muscle) strength in more ways than one. For example, hop tests are associated with quadriceps strength (despite being influenced by fear of re-injury) and are recommended as part of the return to sport testing to assess the overall knee function.

+STUDY REFERENCE

West T, Bruder A, Crossley K, Girdwood M, Scholes M, To L, Couch J, Evans S, Haberfield M, Barton C, Roos E, De Livera A, Culvenor A (2023) Does the one-leg rise test reflect quadriceps strength in individuals following anterior cruciate ligament reconstruction? Phys Ther Sport, 63,104-111.

SUPPORTING REFERENCE

  1. Lepley LK. Deficits in Quadriceps Strength and Patient-Oriented Outcomes at Return to Activity After ACL Reconstruction: A Review of the Current Literature. Sports Health. 2015;7(3):231-8. 10.1177/1941738115578112
  2. Grindem H, Snyder-Mackler L, Moksnes H, Engebretsen L, Risberg MA. Simple decision rules can reduce reinjury risk by 84% after ACL reconstruction: the Delaware-Oslo ACL cohort study. Br J Sports Med. 2016;50(13):804-8. 10.1136/bjsports-2016-096031
  3. Culvenor AG, Ruhdorfer A, Juhl C, Eckstein F, Øiestad BE. Knee extensor strength and risk of structural, symptomatic, and functional decline in knee osteoarthritis: a systematic review and meta-analysis. Arthrit Care Res. 2017;69(5):649-58. 10.1002/acr.23005
  4. Culvenor AG, Collins NJ, Guermazi A, Cook JL, Vicenzino B, Whitehead TS, et al. Early patellofemoral osteoarthritis features one year after anterior cruciate ligament reconstruction: symptoms and quality of life at three years. Arthrit Care Res. 2016;68(6):784-92. 10.1002/acr.22761
Does the one-leg rise… By Dr Christina Le