The role of weightbearing in the clinical assessment of knee joint position sense

Knee osteoarthritis patients assessed during walking for ankle inversion movement discrimination sensitivity

Background: Knee osteoarthritis (KOA) is a common musculoskeletal condition that affects dynamic balance control and increases the risk of falling during walking. However, the mechanisms underlying this are still unclear. Diminished ankle proprioception during walking has been found to be related to fear of falling in older adults, with a gender difference in incidence of falling. This study aimed to determine 1) whether ankle inversion proprioceptive acuity during walking is impaired in patients with KOA; and 2) whether there is any difference between genders. Methods: Thirty-two patients with KOA (F:M = 17:15, Median age = 52.5, BMI = 22.3 ± 3.0) and 34 healthy controls without KOA (HC) (F:M = 17:17; median age = 49.0, BMI = 22.5 ± 2.7) were recruited. In patients with KOA, ankle inversion proprioceptive acuity was measured on the affected side using the ankle inversion discrimination apparatus for walking (AIDAW), whilst HC were assessed on a randomly selected side. Two-way (2*2) analysis of variance (ANOVA) was performed to determine the main effects and interaction between gender and KOA condition. Results: Two-way ANOVA showed a significant KOA main effect (F = 26.6, p < 0.001, ƞp 2 = 0.3) whereby AIDAW scores during walking for individuals with KOA were significantly lower than those without KOA (KOA vs. HC: 0.746 ± 0.057 vs. 0.807 ± 0.035). There was neither a gender main effect nor interaction (both p > 0.05). Conclusion: Individuals with KOA demonstrated lower ankle proprioception scores during walking compared to their healthy counterparts, with a similar level of impairment in ankle proprioceptive acuity between male and female patients. A low score may contribute to an increased risk of falling in the KOA population. The current findings suggest the need for global concern about lower limb proprioception in the clinical management of KOA.

The effectiveness of fatigue on repositioning sense of lower extremities: systematic review and meta-analysis

INTRODUCTION

An injury can significantly harm both individual and team performance. One of the most important risk factors for sports-related injuries, especially non-collision injuries, is fatigue. It seems that poor proprioception may play an essential role to impose athletes to further injuries. This systematic review and meta-analysis aimed to examine the effectiveness of fatigue on the repositioning sense of the lower extremity joints.

METHOD

The electronic databases, including PubMed, Web of Science, Scopus, and Google Scholar were systematically searched from inception to 11January 2024. The obtained records were exported to the EndNote Software version 8. Then, two investigators examined the records independently to find eligible studies based on the inclusion/exclusion criteria. In the case of disagreements, a consequence method was utilized. The quality of the eligible studies was evaluated using the Downs and Black checklist. Comprehensive Meta-Analysis (CMA) software ver. 3 software was used for statistical analysis. Q-test and I2 were employed to examine the data homogeneity. In addition, considering the risk of bias, the Funnel Plot and trim-and-fill method were used.

RESULTS

After reviewing the titles and abstracts of 3883 studies found in the selected databases, 43 articles were found to be eligible to include in meta-analyses. The results showed that fatigue led to a significant increase in the active absolute error of the knee (SDM = 0.524, 95% CI = 0.406-0.841), ankle in the horizontal plane (SDM = 0.541, 95% CI = 0.367-0.715), ankle in the sagittal plane (SDM = 0.443, 95% CI = 0.088-0.798), and hip (SDM = 0.988, 95% CI = 0.135-1.841). However, fatigue had no significant effects on the passive absolute error of the knee and ankle in horizontal plane and relative angular error of the knee.

CONCLUSION

Fatigue can diminish the active joint position sense of the lower extremities and thus may increase the risk of injury by reducing proprioception. Therefore, future research could be conducted to investigate the potential impact of integrated fatigue-mitigating exercises into athletes' training programs, with the aim of reducing the incidence of sports-related injuries.

Reference value of knee position sense in weight-bearing and non-weight-bearing conditions

BACKGROUND

Our study aimed to identify age-related changes in knee proprioception to provide reference values for weight-bearing (WB) and non-weight-bearing (NWB) conditions and to identify factors (age, WB condition, dominance, and sex) that can affect knee proprioception.

METHODS

A total of 84 healthy adult men and women were recruited. Active knee joint position sense (JPS) was measured using a digital inclinometer for knee proprioception. The participants performed the required movements actively, with verbal feedback from the examiner, slowly moving to the target angles (30° and 50°) and maintaining them for 5 s before returning to the starting position. Afterward, without assistance from the examiner, the participants actively moved back to the same angle, and the examiner confirmed the angles. This procedure was repeated twice for each target angle, and the average values were used as the data. The participants were barefoot, wearing shorts, and closed their eyes while the measurements were obtained. The measurements were first obtained on the dominant side under the NWB conditions. When a change in posture was needed during the measurement, the participants sat in a resting position for 2 min.

RESULTS

Except for age, all other factors (WB condition, dominance, sex) were not statistically significant. Age showed a significant difference in knee JPS, except for the non-dominant side at 30° and the dominant side at 50° in the NWB condition.

CONCLUSION

This study indicates that the WB condition, dominant side, and sex need not be considered when measuring and assessing knee JPS. Age shows a negative correlation with knee joint position sense, and the reference values presented in this study can be used as objective target values during the rehabilitation process.

Functional leg performance 2 years after ACL surgery: a comparison between InternalBrace™-augmented repair versus reconstruction versus healthy controls

BACKGROUND

While clinical and patient-reported outcomes have been investigated in patients after InternalBrace™-augmented anterior cruciate ligament repair (ACL-IB), less is known regarding restoration of functional performance. We aimed to determine differences in functional performance within and between patients 2 years after ACL-IB, patients 2 years after ACL reconstruction (ACL-R), and healthy controls.

MATERIALS AND METHODS

A total of 29 ACL-IB, 27 ACL-R (hamstring autograft), and 29 controls performed single-leg hop (maximum forward distance hop, SLH; side hop > 40 cm in 30 s, SH), proprioception (knee joint position sense at 30° and 60° flexion), and dynamic postural balance (Y Balance) tests. Differences were calculated within groups (side-to-side difference) and between the involved leg of patients and the non-dominant leg of controls, and were evaluated to predefined statistical (P < 0.05), clinically relevant, and methodological (smallest detectable change) thresholds. The number of exceeded thresholds represented no (0), small (1), moderate (2), or strong (3) differences. In addition, the relative number of participants achieving leg symmetry (≥ 90%) and normal performance (≥ 90% of the average performance of the non-dominant leg of controls) were compared between groups (chi-squared tests, P < 0.05).

RESULTS

We observed no-to-moderate leg differences within ACL-IB (moderate difference in hops) and within ACL-R (moderate difference in knee proprioception), no leg differences between patient groups, no-to-small leg differences between ACL-IB and controls, and no leg differences between ACL-R and controls in functional performance. However, two patients in ACL-IB and ACL-R, respectively, passed the hop pretest only with their uninvolved leg, and fewer patients after ACL-IB and ACL-R than controls reached a leg symmetry and normal leg performance of controls in SLH (P < 0.001).

CONCLUSIONS

Functional performance seems to be comparable 2 years postoperatively between ACL-IB and ACL-R for a specific subgroup of patients (i.e., proximal ACL tears, moderate activity level). However, the presumed advantage of comparable functional outcome with preserved knee structures after augmented ACL repair compared with ACL-R, and the tendency of both patient groups toward leg asymmetry and compromised single-leg hop performance in the involved legs, warrants further investigation. Level of Evidence Level III, case-control study. Trial registration clinicaltrials.gov, NCT04429165 (12/09/2020). Prospectively registered, https://clinicaltrials.gov/ct2/show/NCT04429165 .

Known-group validity of passive knee joint position sense: a comparison between individuals with unilateral anterior cruciate ligament reconstruction and healthy controls

BACKGROUND

Knee joint position sense (JPS) might be negatively affected after injuries to the anterior cruciate ligament (ACL). Recent systematic reviews suggest further investigation of psychometric properties, including validity, of knee JPS tests following ACL reconstruction (ACLR). This study investigated the known-group validity by comparing knee JPS errors between individuals who underwent unilateral ACLR and healthy controls.

METHODS

This cross-sectional study involved 36 men, including 19 after ACLR (ACLR group) and 17 healthy controls (control group). In both groups, the absolute error (AE), constant error (CE) and variable error (VE) of passive knee JPS were calculated in the flexion and extension directions, for two target angles (30° and 60° flexion) per direction. Discriminative validity was evaluated by comparing JPS errors between the operated and non-operated knees in the ACLR group. Known-group validity was evaluated by comparing JPS errors between the operated knees in the ACLR group and the asymptomatic non-dominant knees of healthy controls.

RESULTS

Mean AE, CE and VE for all tests were 4.1°, - 2.3° and 3.6° for the operated knees in the ACLR group, 5.5°, - 2.6° and 3.3° for the non-operated knees in the ACLR group and 4.6°, - 2.6° and 3.3° for the non-dominant knees in the control group, respectively, regardless of the test direction and target angle. The operated knees in the ACLR group did not show significantly greater JPS errors compared to the contralateral knees in the ACLR group and to the non-dominant knees in the control group (p ≥ 0.05). On the other hand, the non-operated knees showed significantly greater AE for the 0°-60° flexion test (p = 0.025) and CE for the 0°-30° flexion test (p = 0.024) than the operated knees in the ACLR group. JPS errors did not significantly differ in the operated knees in the ACLR group based on the direction of movement and the target angle. However, the errors were significantly higher when the knee was moved through a greater range compared to that of a lesser range between the starting and target angles.

CONCLUSION

The ACLR knees did not show greater passive JPS errors than the contralateral or control knees. The direction of movement and target angle did not influence the JPS acuity after ACLR. However, higher JPS errors were evident when the knee was moved through a greater range compared to a lesser range of motion. Further studies investigating the psychometric properties of standardized JPS tests following ACLR are warranted.

A reliable and efficient adaptive Bayesian method to assess static lower limb position sense

BACKGROUND

Lower limb proprioception is critical for maintaining stability during gait and may impact how individuals modify their movements in response to changes in the environment and body state, a process termed "sensorimotor adaptation". However, the connection between lower limb proprioception and sensorimotor adaptation during human gait has not been established. We suspect this gap is due in part to the lack of reliable, efficient methods to assess global lower limb proprioception in an ecologically valid context.

NEW METHOD

We assessed static lower limb proprioception using an alternative forced choice task, administered twice to determine test-retest reliability. Participants stood on a dual-belt treadmill which passively moved one limb to stimulus locations selected by a Bayesian adaptive algorithm. At the stimulus locations, participants judged relative foot positions and the algorithm estimated the point of subjective equality (PSE) and the uncertainty of lower limb proprioception.

RESULTS

Using the Bland-Altman method, combined with Bayesian statistics, we found that both the PSE and uncertainty estimates had good reliability.

COMPARISON WITH EXISTING METHOD(S)

Current methods assessing static lower limb proprioception do so within a single joint, in non-weight bearing positions, and rely heavily on memory. One exception assessed static lower limb proprioception in standing but did not measure reliability and contained confounds impacting participants' judgments, which we experimentally controlled here.

CONCLUSIONS

This efficient and reliable method assessing lower limb proprioception will aid future mechanistic understanding of locomotor adaptation and serve as a useful tool for basic and clinical researchers studying balance and falls.

A reliable and efficient adaptive Bayesian method to assess static lower limb position sense

Background

Lower limb proprioception is critical for maintaining stability during gait and may impact how individuals modify their movements in response to changes in the environment and body state, a process termed "sensorimotor adaptation". However, the connection between lower limb proprioception and sensorimotor adaptation during human gait has not been established. We suspect this gap is due in part to the lack of reliable, efficient methods to assess global lower limb proprioception in an ecologically valid context.

New Method

We assessed static lower limb proprioception using an alternative forced choice task, administered twice to determine test-retest reliability. Participants stood on a dual-belt treadmill which passively moved one limb to stimulus locations selected by a Bayesian adaptive algorithm. At the stimulus locations, participants judged relative foot positions and the algorithm estimated the point of subjective equality (PSE) and the uncertainty of lower limb proprioception.

Results

Using the Bland-Altman method, combined with Bayesian statistics, we found that both the PSE and uncertainty estimates had good reliability.

Comparison with Existing Methods

Current methods assessing static lower limb proprioception do so within a single joint, in non-weight bearing positions, and rely heavily on memory. One exception assessed static lower limb proprioception in standing but did not measure reliability and contained confounds impacting participants' judgments, which we experimentally controlled here.

Conclusions

This efficient and reliable method assessing lower limb proprioception will aid future mechanistic understanding of locomotor adaptation and serve as a useful tool for basic and clinical researchers studying balance and falls.

Proprioceptive Neuromuscular Facilitation Protocol for Thumb Osteoarthritis: A Pilot Study

BACKGROUND

Osteoarthritis (OA) of the thumb carpometacarpal (CMC) joint often presents with joint instability and proprioceptive deficits. Proprioception has been found to play an important role in the rehabilitative process. The purpose of this study was to evaluate the effectiveness of a proprioceptive training program on pain and function in individuals with early-stage thumb Carpometacarpal joint OA.

METHODS

A double-blind experimental trial using a 2-group pretest/posttest design was used in this pilot study. Participants had a diagnosis of grade I and II thumb CMC joint OA in their dominant hand and a pain rating of >4/10 on Visual Analogue Scale. Participants received either standard treatment (control group) or standard treatment plus a proprioceptive training program (experimental group). Outcome measures were lateral pinch strength, pain intensity during activities, and proprioceptive response via joint position sense (JPS) testing.

RESULTS

Twelve individuals (average age of 66.25 years) participated. Both groups had a statistically significant decrease in pain and increase in lateral pinch strength, all occurring with a large effect size but no statistically significant difference between groups. The experimental group experienced a large effect size for JPS testing, whereas the control group experienced a trivial effect size, and there was a statistically significant difference between groups for JPS testing.

CONCLUSIONS

Individuals who completed the proprioceptive training program in this study had an improvement in proprioceptive functioning. This program shows potential for routine inclusion in hand therapy for thumb CMC joint OA; however, additional high-level studies with larger sample sizes are required.

The measurement of proprioceptive accuracy: A systematic literature review

BACKGROUND

Proprioceptive accuracy refers to the individual's ability to perceive proprioceptive information, that is, the information referring to the actual state of the locomotor system, which originates from mechanoreceptors located in various parts of the locomotor system and from tactile receptors located in the skin. Proprioceptive accuracy appears to be an important aspect in the evaluation of sensorimotor functioning; however, no widely accepted standard assessment exists. In this systematic review, our goal was to identify and categorize different methods that are used to assess different aspects of proprioceptive accuracy.

METHODS

A literature search was conducted in 5 different databases (PubMed, SPORTDiscus, PsycINFO, ScienceDirect, and SpringerLink).

RESULTS

Overall, 1139 scientific papers reporting 1346 methods were included in this review. The methods assess 8 different aspects of proprioception: (a) the perception of joint position, (b) movement and movement extent, (c) trajectory, (d) velocity, and the sense of (e) force, (f) muscle tension, (g) weight, and (h) size. They apply various paradigms of psychophysics (i.e., the method of adjustment, constant stimuli, and limits).

CONCLUSION

As the outcomes of different tasks with respect to various body parts show no associations (i.e., proprioceptive accuracy is characterized by site-specificity and method-specificity), the appropriate measurement method for the task needs to be chosen based on theoretical considerations and/or ecological validity.

Correlation and comparison of quadriceps endurance and knee joint position sense in individuals with and without unilateral knee osteoarthritis

Background

Knee osteoarthritis (KOA) is a painful degenerative joint disease that may limit activities of daily living. This study aimed to determine the relationship between quadriceps endurance and knee joint position sense (JPS) in KOA individuals and compare the quadriceps endurance and knee JPS with and without KOA.

Methods

This comparative cross-sectional study was conducted in medical rehabilitation clinics, King Khalid University, Saudi Arabia. This study recruited 50 individuals diagnosed with unilateral KOA (mean age = 67.10 ± 4.36 years) and 50 asymptomatic individuals (mean age = 66.50 ± 3.63 years). Quadriceps isometric endurance capacity (sec) was measured using a fatigue resistance test, and knee JPS (degrees) were assessed using a digital inclinometer and evaluated in sitting and standing positions.

Results

Quadriceps isometric endurance showed a significant moderate negative correlation with knee JPS in 20° of flexion (r = -0.48, p < 0.001); 40° of flexion: r = -0.62, p < 0.001; 60° of flexion: r = -0.58, p < 0.001) in sitting and 20° of flexion (r = -0.25, p = 0.084) in standing position in KOA individuals. When compared to the asymptomatic, the quadriceps endurance was lower (p < 0.001), and knee joint position errors were larger (p < 0.001) in KOA individuals.

Conclusion

Results of this study showed that quadriceps endurance capacity is negatively associated with knee JPS. KOA individuals demonstrated lower quadriceps endurance and larger JPS compared to asymptomatic.

Acute Impact of Proprioceptive Exercise on Proprioception and Balance in Athletes

This study aimed to compare the acute effect of a proprioceptive exercise session and a non-specific exercise session on knee position sense, and the static and dynamic balance of athletes. Sixty male athletes (19.4 ± 1.2 years) participated in a within-subjects repeated-measures study. Knee position sense in closed kinetic chain, and static (BESS test) and dynamic balance (Y-balance test) were measured before and after two exercise sessions, consisting of 10 min of non-specific exercise in a cycle-ergometer or proprioceptive exercise with an unstable platform. Overall, both exercise sessions significantly improved knee position sense, BESS score, and YBT composite score, and no differences were detected between proprioceptive and non-specific sessions (knee position sense, −6.9 ± 65.2% vs. −11.5 ± 75.0%, p = 0.680; BESS, −19.3 ± 47.7% vs. −29.03 ± 23.5%, p = 0.121; YBT, 2.6 ± 2.7% vs. 2.2 ± 2.2%, p = 0.305). Twenty athletes did not improve knee position sense after the exercise session (non-responders). When analyzing only the exercise responders, both sessions improved knee position sense, but the improvement was greater after the proprioceptive exercise session (56.4 ± 25.6% vs. 43.8 ± 18.9%, p = 0.023). In conclusion, a single proprioceptive, as well as non-specific, exercise session increased knee position sense and balance. The proprioceptive exercise seems to be more effective in improving joint position sense when considering only athletes who respond to the intervention.

Valgus Control Feedback and Taping Improves the Effects of Plyometric Exercises in Women With Dynamic Knee Valgus

BACKGROUND

Female athletes are more predisposed to anterior cruciate ligament (ACL) injuries in comparison with their male counterparts. Research on ACL injury prevention strategies has demonstrated beneficial effects of plyometric exercises and feedback (FB) during the exercises. FB has resulted in reductions in vertical ground-reaction force and kinematic risk factors associated with ACL injury. Furthermore, taping (TP) may draw attention to the restriction created by the tape and serve as real-time biofeedback. The additional influence of FB and TP on plyometric exercises has not been determined.

HYPOTHESIS

FB and TP interventions delivered during plyometric exercises would result in positive changes in biomechanics and muscle onset in female athletes displaying dynamic knee valgus.

DESIGN

Controlled trial.

SETTING

University research laboratory.

LEVEL OF EVIDENCE

Level 2.

METHODS

Forty-eight active female athletes were divided into 3 groups: control (n = 16), plyometric training with FB (n = 16), and plyometric training with TP (n = 16). The 2 experimental groups performed a 6-week exercise program with either FB or TP. The control group continued its regular team schedule. Knee joint position sense, landing error scoring system (LESS), and the onset of muscle activation (the point at which muscle activation exceeds 3 standard deviations over baseline and continued above this threshold for at least 25 ms) before landing for the rectus femoris, vastus medialis, vastus lateralis, gluteus medius, semitendinosus, and biceps femoris during pre- and posttests were measured.

RESULTS

The vastus lateralis onset later in the TP group compared with the FB group (d [95% CI] = 0.64 [0.35-0.82], P = 0.01). Joint position sense accuracy improved only in the TP group (d = -0.63, P = 0.001). Both the FB (d = -0.85, P = 0.001), and TP (d = -0.82, P = 0.001) groups improved in LESS scores.

CONCLUSION

The results of the present study showed that plyometric exercises with FB or TP affect LESS and the onset of the vastus lateralis in active uninjured women with dynamic knee valgus, while TP improves joint position sense. Therefore, when more accurate joint position sense is desired, practitioners may use plyometric with TP. If an improved LESS score is desired, plyometrics with either TP or FB are acceptable.

CLINICAL RELEVANCE

Our findings indicate that female athletes may benefit more when completing a plyometric training program with a TP versus an FB. Trainers, coaches, and clinicians should consider utilizing instructions that promote an external focus when implementing plyometric training programs with male athletes.

Safety and Effectiveness of a Perturbation-based Neuromuscular Training Program on Dynamic Balance in Adolescent Females: A Randomized Controlled Trial

BACKGROUND

Adolescent females are at much greater risk for ACL injury than their male counterparts when participating in the same sports. Preventative and pre-operative rehabilitation neuromuscular (NM) exercise programs are often recommended to improve knee function and reduce injury rates. The effectiveness of perturbation-based NM training program has been established in an adult population but has yet to be investigated in the at-risk adolescent female population.

PURPOSE

To determine the effectiveness of a perturbation-based NM exercise program in a group of physically active adolescent females.

STUDY DESIGN

Prospective randomized trial.

METHODS

Twenty-four healthy and an exploratory group of 10 ACL-injured females (ages 12-18) were equally randomized into a perturbation-based NM training or control group and evaluated before and after a five-week intervention period. The primary outcome of dynamic balance was measured using the Y-Balance test (YBT); secondary outcome measures included lower limb strength, proprioception, and flexibility.

RESULTS

The perturbation-based NM training intervention was safely completed by all participants but had no significant effect on YBT scoring, lower limb strength, proprioception or flexibility in either the healthy or ACL-injured groups.

CONCLUSIONS

Perturbation-based NM training is safe, but may offer little preventative benefit for healthy or pre-operative rehabilitation benefit for ACL-injured adolescent females. Future research should examine whether the effectiveness of perturbation-based NM training is influenced by the length of the training intervention, training intensity, or when it is combined with other forms of prophylactic or pre-surgical rehabilitation frequently used with at-risk adolescent females who regularly participate in sport.

LEVEL OF EVIDENCE

Level 3.

Recent Ankle Injury, Sport Participation Level, and Tests of Proprioception

OBJECTIVE

Assessing the effects of ankle injury and sport participation level on ankle proprioceptive sensitivity using a joint position reproduction (JPR) test and an inversion movement extent discrimination test.

DESIGN

Cross-sectional.

SETTING

Biomechanics lab.

PARTICIPANTS

Forty-five student athletes ages 21-30 (mean = 24.8 y).

MAIN OUTCOME MEASURES

Participants were tested for ankle inversion sensitivity using 2 devices; movement reproduction error was obtained from JPR in a non-weight-bearing (N-WB) state at 10° and 15° of inversion, and an ankle proprioceptive sensitivity score was obtained from the active movement extent discrimination apparatus (AMEDA), representing the ability to differentiate 5 inversion movement extents between 10.5° and 14.5°, with testing in both N-WB and weight-bearing (WB) states.

RESULTS

For the 34 athletes with no ankle injury in the previous 12 months, the sensitivity scores achieved on the AMEDA were significantly higher (P < .01) than those for the 11 athletes with ankle injury, and the injury effect was significantly greater in WB (P = .01). In JPR testing, the 2.96° error of reproduction for athletes with no recent ankle injury was not significantly different from the 3.36° error for those with ankle injury (P = .46). Correlation of current sport participation level with JPR showed less error for higher-level performers (r = .49, P = .001) but no significant relationship to WB or N-WB AMEDA scores (both P > .61). WB AMEDA scores were significantly higher for athletes who had competed at a higher level of sport competition when <18 years old (r = -.57, P < .001).

CONCLUSIONS

Previous ankle sprains affected proprioceptive scores on the WB AMEDA and N-WB AMEDA tests, indicating the sensitivity of the AMEDA movement discrimination test to the effects of ankle injury. The correlation between JPR scores and current level of sport participation suggests the sensitivity of the JPR test to current ankle use.

Development of supine and standing knee joint position sense tests

OBJECTIVES

We aimed to assess the test-retest reliability of a supine and standing knee joint position sense (JPS) test, respectively, and whether they discriminate knees with anterior cruciate ligament (ACL) injury from asymptomatic knees.

DESIGN

Repeated measures and cross-sectional.

SETTING

Research laboratory.

PARTICIPANTS

For test-retest reliability, 24 persons with asymptomatic knees. For discriminative analysis: 1) ACLR - 18 persons on average 23 months after unilateral ACL reconstruction, 2) CTRL - 23 less-active persons, and 3) ATHL - 21 activity level-matched athletes.

MAIN OUTCOME MEASURES

Absolute error (AE) and variable error (VE).

RESULTS

Test-retest reliability was generally highest for AE of the standing test (ICC 0.64-0.91). Errors were less for the standing compared to the supine test across groups. CTRL had greater knee JPS AE (P = 0.005) and VE (P = 0.040) than ACLR. ACLR knees showed greater VE compared to the contralateral non-injured knees for both tests (P = 0.032), albeit with a small effect size (η_p² = 0.244).

CONCLUSIONS

Our standing test was more reliable and elicited lesser errors than our supine test. Less-active controls, rather than ACLR, produced significantly greater errors. Activity level may be a more predominant factor than ACLR for knee JPS ∼2 years post-reconstruction.

Joint position sense in individuals with anterior knee pain

BACKGROUND

Anterior knee pain (AKP) commonly affects both physically active and sedentary individuals and the aetiology is unknown. Altered joint position sense (JPS) impacts accurate motor action and knee joint stability. It is unclear whether people with AKP have altered JPS.

OBJECTIVE

The aim of our study was to investigate JPS in the knees of individuals with AKP.

METHOD

A descriptive cross-sectional study measured JPS in 25 participants with unilateral or bilateral AKP. JPS was measured using active JPS testing during single leg squat (SLS) and active knee extension (AKE) in sitting. Target angles (TA) were self-determined based on each participant's capabilities. The absolute error (AE) was the main outcome measure. Impaired JPS was classified as an AE equal to or greater than five degrees.

RESULTS

There were no significant differences in JPS when comparing the affected and unaffected knees in participants with AKP (p > 0.05). However, a subgroup of participants with altered knee JPS was identified. There was a tendency towards greater knee flexion in the TAs of knees without AKP.

CONCLUSION

Our results showed that JPS is not significantly more impaired in knees with AKP compared with knees without AKP in a group of individuals with AKP. A subgroup with altered JPS in knees with and without AKP was identified. This finding could be because of compensatory gait patterns and the precision of the Vicon 3D motion analysis system.

CLINICAL IMPLICATIONS

Joint position sense should be assessed bilaterally in individuals with AKP.

Does delayed onset muscle soreness affect the biomechanical variables of the drop vertical jump that have been associated with increased ACL injury risk? A randomised control trial

INTRODUCTION

Delayed onset muscle soreness (DOMS) and Anterior Cruciate Ligament (ACL) injuries are both prevalent in sport. It is currently unknown whether DOMS increases ACL injury risk.

AIM

This study aimed to provide preliminary insight on whether DOMS affects ACL injury risk by investigating whether DOMS affects the biomechanical variables of the DVJ that have been identified as risk factors for future ACL injury.

METHODS

This was a randomised control trial involving 32 active individuals aged 18-35 years, with no history of ACL injury. Participants underwent two sessions of force-plate testing and 3D motion analysis of the drop vertical jump (DVJ). The DVJ was chosen as it has been investigated prospectively for association with future ACL injury. Initial testing was followed by randomisation to DOMS or control group. The DOMS group underwent a DOMS-inducing exercise protocol, the control group did not. Both groups were re-tested 48 h after initial testing. Five variables of the DVJ that have been associated with future ACL injury were chosen for analysis - peak knee flexion angle, peak vertical ground reaction force, ground contact time, peak knee abduction angle & peak knee abduction moment. Between-group differences were compared using a two-way mixed analysis of variance; alpha level set to 0.05.

RESULTS

DOMS was successfully induced in all participants of the DOMS group however no statistically significant group x time interactions were found for any of the five variables analysed.

CONCLUSIONS

DOMS did not affect the biomechanical variables of the DVJ that have been associated with future ACL injury. By extension, this may suggest that DOMS might not affect ACL injury risk. However, it is also possible that certain attributes of the DVJ meant that any effect of DOMS was simply unable to be quantified, even if an effect existed. All considered, our position is that conclusion cannot be drawn from this study alone on whether DOMS affects ACL injury risk. Further research is required.

Effects of Combining Running and Practical Duration Stretching on Proprioceptive Skills of National Sprinters

Romero-Franco, N, Párraga-Montilla, JA, Molina-Flores, EM, and Jiménez-Reyes, P. Effects of combining running and practical duration stretching on proprioceptive skills of national sprinters. J Strength Cond Res 34(4): 1158-1165, 2020-Practical duration stretching after aerobic activities is a recommended component of the first part of warm-up because of its effects on performance. However, its effects on proprioceptive skills are unknown. This study aimed to analyze the effects of running and practical duration static stretching (SS) and dynamic stretching (DS) on postural balance and the joint position sense (JPS) of national sprinters. Thirty-two national sprinters were randomly classified into a SS group (n = 11), DS group (n = 11), or control group (n = 10). Static stretching performed 5 minutes of running and short-duration (20 seconds) static stretches; DS performed 5 minutes of running and short-duration dynamic (20 seconds) stretches; and the control group performed 5 minutes of running. Before and after the intervention, unipedal static postural balance and knee JPS were evaluated. Static stretching exhibited a more centralized center of pressure in the medial-lateral plane for unipedal static postural balance in right-leg support after stretching (p = 0.005, d = 1.24), whereas DS showed values further from the center after stretching for the same unipedal support compared with baseline (p = 0.042, d = 0.49), and the control group remained stable (p > 0.05). Joint position sense did not show significant differences in any group (p > 0.05). In conclusion, combining running and practical duration SS may be beneficial for right-leg postural stabilization, whereas DS may be partly and slightly deleterious. Both SS and DS combined with running and running alone have neutral effects on knee JPS. Sports professionals should consider running and practical duration SS as part of the warm-up of sprinters to partly improve unipedal static postural balance.

Effects of Warm-Up and Fatigue on Knee Joint Position Sense and Jump Performance

The purpose of this study was to evaluate the effects of a warm-up and fatigue protocol on the vertical jump and knee joint position sense of sprinters. Thirty-two sprinters were randomly allocated to either a control group (CONT) or a plyometric group (PLYO) that performed a warm-up, followed by a high-intensity plyometric protocol. Absolute (AAE), relative (RAE), and variable (VAE) angular errors and vertical jump were evaluated before and after the warm-up, as well as after the plyometric protocol and again 5 min later. After the warm-up, athletes improved RAE and jump performance. After the plyometric protocol, scores on the RAE, VAE, and the vertical jump performance worsened compared to the control group and to the values obtained after the warm-up. Five minutes later, RAE and vertical jump continued to be impaired. AAE did not show significant differences. The vertical jump is improved after the warm-up, although it is deteriorated after high-intensity plyometry. Regarding knee proprioception, the lack of impairments in the AAE make unclear the effects of the plyometric exercises on knee proprioception.

Reliability and measurement precision of concentric-to-isometric and eccentric-to-isometric knee active joint position sense tests in uninjured physically active adults

OBJECTIVES

Proprioception is important because it is used by the central nervous system to mediate muscle control of joint stability, posture, and movement. Knee active joint position sense (AJPS) is one representation of knee proprioception. The purpose of this study was to establish the intra-tester, inter-session, test-retest reliability of concentric-to-isometric (seated knee extension; prone knee flexion) and eccentric-to-isometric (seated knee flexion; prone knee extension) knee AJPS tests in uninjured adults.

DESIGN

Descriptive.

SETTING

University laboratory.

PARTICIPANTS

Six males, six females (age 26.2 ± 5.7 years; height 171.1 ± 9.6 cm; mass 71.1 ± 16.6 kg).

MAIN OUTCOME MEASURES

Mean absolute error (AE; °); intraclass correlation coefficient (ICC) (2,1); standard error of measurement (SEM; °).

RESULTS

Mean AE ranged from 3.18° to 5.97° across tests. The ICCs and SEMs were: seated knee extension 0.13, 1.3°; prone knee flexion 0.51, 1.2°; seated knee flexion 0.31, 1.7°; prone knee extension 0.87, 1.4°.

CONCLUSIONS

The prone knee flexion and prone knee extension tests demonstrated moderate to good reliability. Prone knee flexion and prone knee extension AJPS tests may be useful in cross-sectional studies estimating how proprioception contributes to knee functional joint stability or prospective studies estimating the role of proprioception in the onset of knee injury.

Does knee joint proprioception alter following medial patellofemoral ligament reconstruction?

BACKGROUND

This study firstly aimed to determine whether proprioception deficits, as measured by joint position sense (JPS), occur in people following recurrent patellar dislocations. Secondly, to determine whether JPS changes following medial patellofemoral ligament reconstruction (MPFL) reconstruction for patellar instability.

METHODS

Thirty people following recurrent patellar dislocation were recruited. Pre-operative JPS was assessed using the passive angle reproduction test. Through this, an assessor moved a participant's limb to a target position. This was returned to neutral, before finally moving the limb again, whilst requiring the participant to indicate when they thought the target angle was reached. The actual angular error (AAE) was calculated as the difference between the perceived angle and target angle. Clinical outcomes included the Kujala Patellofemoral Disorder Score, the International Knee Documentation Committee (IKDC) form, pain, knee motion, extensor muscle strength and frequency of patellar dislocation. Outcomes were assessed pre-operative, 6 weeks, 3 and 12 months.

RESULTS

Mean AAE was 2.2° (inner range) to 3.9° (mid-range); this was not clinically significant. There was no statistically significant difference between the baseline-and-6 week, 6 week-and-3 month or baseline-and-12 month AAE measures (p=0.38 to 1.00). There was a statistically significant improvement in functional outcomes as measured by the Kujala score, IKDC form, reduced pain and increased extension strength from baseline to 12 months (p<0.01).

CONCLUSIONS

Following recurrent patellar dislocation, patients exhibit minimal deficits in JPS. Whilst MPFL reconstruction significantly improved clinical and functional outcomes for this population, this operation did not significantly alter JPS during the first post-operative year.

Biomechanics of the heel-raise test performed on an incline in two knee flexion positions

BACKGROUND

Although single-legged heel-raise cycles are often performed on an incline in different knee flexion positions to discriminate the relative contribution of the triceps surae muscles, detailed kinematic and kinetic analyses of this procedure are not available. Our study characterizes and compares the biomechanics and clinical outcomes of single-legged heel-raise cycles performed to volitional exhaustion on an incline with the knee straight (0°) and bent (45°), considering the effect of sex and age.

METHODS

Fifty-six male and female volunteers, with equal numbers of younger (20 to 40 years of age) and older (40 to 60 years of age) individuals, completed a maximal number of heel-raise cycles on an incline at both nominal knee angles. Kinematic and kinetic data were acquired during testing using a 3D motion capturing system and multi-axial force plate. The impact of fatigue on performance was quantified using changes in maximal voluntary isometric contraction force and biomechanical performance of cycles.

FINDINGS

Overall, participants completed three more cycles and maintained better biomechanical performance with 45° than 0° of knee flexion. More precisely, the decreases in maximal heel-raise heights, plantar-flexion angles at maximal height and ranges of ankle motion per cycle were all smaller with the knee bent. However, several outcomes indicated similar plantar-flexion fatigue at both knee angles. Males demonstrated a more rapid decline in peak ground reaction forces during testing; but otherwise, neither sex nor age significantly impacted outcomes.

INTERPRETATION

It is concluded that the differences discerned here in the biomechanics of single-legged heel-raise cycles performed at 0° and 45° of knee flexion to volitional exhaustion on an incline may be too small to identify in clinical settings or reflect substantial alterations in the relative contribution of the triceps surae muscles.

A systematic review to determine the reliability of knee joint position sense assessment measures

BACKGROUND

The assessment of joint position sense (JPS) is the most widely used measurement of knee proprioceptive capability within the literature. However, it remains unclear what the most reliable method is to assess this. The purpose of this study was to determine the intra- and inter-rater reliability of the various methods used to assess knee JPS.

METHODS

A systematic review of published and unpublished literature sources was conducted up to June 2012. All studies principally assessing the reliability (intra- or inter-rater) or reproducibility of a JPS of the knee were included. The methodological quality of each study was reviewed using the Critical Appraisal Skills Programme tool.

RESULTS

A total of 18 studies were eligible, assessing the reliability of JPS with 456 knees. The reliability of four methods of JPS has been recorded: position replication using a model, image recorded angulation, electrogoniometry and dynamometry/angular motion chair. Intra-rater reliability was good for the assessment of JPS using photographs and digital images, and replicating knee position using a paper model, this was good but variable when electrogoniometry was used, and moderate but variable when assessed using dynamometry/angle motion chairs. The assessment of JPS by image recorded angulation, electrogoniometry and dynamometry/angular motion chair has demonstrated good inter-rater reliability.

CONCLUSIONS

Whilst JPS methods appear to have variable reliability, the four assessment methods should be further assessed with pathological populations such as those following patellar dislocation or anterior cruciate ligament rupture. This will better facilitate the generalisability of JPS assessment methods to inform clinical practice.

Menstrual cycle and knee joint position sense in healthy female athletes

PURPOSE

The aim of this study was to investigate the effect of menstrual cycle on knee joint position sense (JPS) in healthy female athletes.

METHODS

Sixteen healthy female athletes participated in this study. Serum estrogen and progesterone levels were collected during the three phases of menstrual cycle. The knee JPS was also measured during the same phases using a system comprise of skin markers, digital photography, and AutoCAD software. Absolute angular errors were calculated as well as changes in hormone levels between the three phases.

RESULTS

Serum estrogen concentration was significantly higher during the mid-luteal (179.5 Pg/ml) and mid-follicular (125.6 Pg/ml) phases as compared with the early-follicular (menses) (22.8 Pg/ml) phase (P = 0.0001). Also serum progesterone concentration was significantly higher during the mid-luteal phase (7.35 Ng/ml) as compared with the menses (0.58 Ng/ml) and mid-follicular (0.5 Ng/ml) phases (P = 0.0001). The greatest amount of mean (SD) value of absolute error was at menses (4.2°), and the least amount of it was at mid-luteal (2.5°) phase. Also, a significant difference was observed within three phases of menstrual cycle (P = 0.025).

CONCLUSION

The result of this study suggests that healthy female athletes have different levels of knee JPS across a menstrual cycle. JPS accuracy decreases in menses, when circulating sex-hormones levels are low. Therefore, female athletes are at higher risk of injury at menses and improving their awareness regarding the knee injury risk factors can be a fundamental step toward preventing injuries.

LEVEL OF EVIDENCE

Case series, Level IV.

Lower extremity joint position sense in runners with and without a history of knee overuse injury

Kinematic and kinetic analyses are routinely implemented to determine if gait differences exist between runners with and without a history of knee injury. Hip and knee kinematic differences have been reported between knee injured and non-injured runners. Yet, there is no consensus on whether these differences are the primary variables contributing to knee injury. Furthermore, there may be additional underlying factors that contribute to the development of injury that cannot be determined by gait analysis. The purpose of this investigation was to determine if joint position sense differences exist in runners with and without a history of knee overuse injury. Sagittal plane knee and hip joint position sense was measured in 13 runners with a history of knee overuse injury and 13 runners with no history of knee overuse injury. Absolute joint position replication error was measured during both a weight bearing and a non-weight bearing condition. Joint position replication errors at each joint were compared among groups and task using a two-way ANOVA with joint task as the repeated measure. Knee and hip joint replication errors were similar between both groups. The weight bearing and non-weight bearing tasks resulted in similar joint position replication errors. There were no interaction effects. In conclusion, knee flexion and hip adduction joint position sense is similar in runners with and without a history of knee overuse injury. Therefore, joint position sense measured via weight bearing and non-weight bearing joint position replication tasks may not play an important role in the development of knee overuse injury.

Effects of cold water immersion on knee joint position sense in healthy volunteers

The purpose of this study was to determine the effects of cryotherapy, in the form of cold water immersion, on knee joint position sense. Fourteen healthy volunteers, with no previous knee injury or pre-existing clinical condition, participated in this randomized cross-over trial. The intervention consisted of a 30-min immersion, to the level of the umbilicus, in either cold (14 ± 1 °C) or tepid water (28 ± 1 °C). Approximately one week later, in a randomized fashion, the volunteers completed the remaining immersion. Active ipsilateral limb repositioning sense of the right knee was measured, using weight-bearing and non-weight-bearing assessments, employing video-recorded 3D motion analysis. These assessments were conducted immediately before and after a cold and tepid water immersion. No significant differences were found between treatments for the absolute (P = 0.29), relative (P = 0.21) or variable error (P = 0.86). The average effect size of the outcome measures was modest (range -0.49 to 0.9) and all the associated 95% confidence intervals for these effect sizes crossed zero. These results indicate that there is no evidence of an enhanced risk of injury, following a return to sporting activity, after cold water immersion.

Proprioception in knee osteoarthritis: a narrative review

OBJECTIVE

To give an overview of the literature on knee proprioception in knee osteoarthritis (OA) patients.

METHOD

A literature search was performed and reviewed using the narrative approach.

RESULTS

(1) Three presumed functions of knee proprioception have been described in the literature: protection against excessive movements, stabilization during static postures, and coordination of movements. (2) Proprioceptive accuracy can be measured in different ways; correlations between these methods are low. (3) Proprioceptive accuracy in knee OA patients seems to be impaired when compared to age-matched healthy controls. Unilateral knee OA patients may have impaired proprioceptive accuracy in both knees. (4) Causes of impaired proprioceptive accuracy in knee OA remain unknown. (5) There is currently no evidence for a role of impaired proprioceptive accuracy in the onset or progression of radiographic osteoarthritis (ROA). (6) Impaired proprioceptive accuracy could be a risk factor for progression (but not for onset) of both knee pain and activity limitations in knee OA patients. (7) Exercise therapy seems to be effective in improving proprioceptive accuracy in knee OA patients.

CONCLUSIONS

Recent literature has shown that proprioceptive accuracy may play an important role in knee OA. However, this role needs to be further clarified. A new measurement protocol for knee proprioception needs to be developed. Systematic reviews focusing on the relationship between impaired proprioceptive accuracy, knee pain and activity limitations and on the effect of interventions (in particular exercise therapy) on proprioceptive accuracy in knee OA are required. Future studies focusing on causes of impaired proprioceptive accuracy in knee OA patients are also needed, taking into account that also the non-symptomatic knee may have proprioceptive impairments. Such future studies may also provide knowledge of mechanism underlying the impact of impaired proprioceptive accuracy on knee pain and activity limitations.

Warming-up before sporting activity improves knee position sense

OBJECTIVE

To evaluate the effects of a warm-up program on knee joint position sense in karatekas.

DESIGN

Repeated measures design.

SETTING

Research laboratory.

PARTICIPANTS

Ten young amateur karatekas (17.6 +/- 4.0 years of age).

MAIN OUTCOME MEASURES

Knee joint position sense evaluated before and immediately after a warm-up program through active repositioning in open kinetic chain (OKC) and closed kinetic chain (CKC).

RESULTS

At baseline testing no differences were observed between OKC and CKC in absolute (4.1 +/- 1.6 degrees vs. 3.4 +/- 2.0 degrees) and relative angular errors (2.4 +/- 3.4 degrees vs. 2.1 +/- 3.5 degrees). After the warm-up program, a significant decrease in absolute angular error was observed only in CKC (from 3.4 +/- 2.0 degrees to 1.8 +/- 0.5, p < 0.05). Additionally, in CKC the subjects reduced the relative angular error to approximately zero (from 2.1 +/- 3.5 degrees to -0.01 +/- 1.6 degrees) and decreased the variability of the responses, expressed by the decrease in standard deviation of the relative errors.

CONCLUSIONS

The warm-up program enhanced knee joint position sense only in CKC. Since no effects were detected in OKC, the evaluation of the effects of warm-up on knee joint position sense using merely an OKC technique would underestimate the valuable role of warm-up.

Unconstrained shoulder joint position sense does not change with body orientation

Our knowledge of the role of muscle activation on proprioception is incomplete. Previous work has either focused on comparing active and passive motions or manipulated both muscle activation and joint angles simultaneously. We conducted an experiment at the shoulder in which subjects' trunks were tilted backwards to decouple joint angle from joint torque. Twenty three healthy subjects underwent testing in an unconstrained joint position sense task. Kinematics were measured with a magnetic tracking device. The joint position sense task consisted of subjects moving their arms to a predetermined orientation in space with the help of visual feedback from the magnetic tracking device presented to the subjects through a head-mounted display. Subjects were then asked to reproduce the presented joint position in the absence of visual feedback. The protocol was performed under two tilts: upright and trunk tilted back 45 degrees. This allowed for a comparison of joint position sense at different joint angles (at the same resistive torque) and at different resistive torques (at the same joint angles). When comparing these two tilts, we found that matching based on elevation angle demonstrated no significant difference, while matching based on torques did find differences. These results implicate elevation angle at the shoulder as playing a more important role in modulating joint position sense than joint torque.

The effects of stochastic resonance electrical stimulation and neoprene sleeve on knee proprioception

Background

A variety of knee injuries and pathologies may cause a deficit in knee proprioception which may increase the risk of reinjury or the progression of disease. Stochastic resonance stimulation is a new therapy which has potential benefits for improving proprioceptive function. The objective of this study was to determine if stochastic resonance (SR) stimulation applied with a neoprene sleeve could improve knee proprioception relative to a no-stimulation/no-sleeve condition (control) or a sleeve alone condition in the normal, healthy knee. We hypothesized that SR stimulation when applied with a sleeve would enhance proprioception relative to the control and sleeve alone conditions.

Methods

Using a cross-over within subject design, twenty-four healthy subjects were tested under four combinations of conditions: electrical stimulation/sleeve, no stimulation/sleeve, no stimulation/no sleeve, and stimulation/no sleeve. Joint position sense (proprioception) was measured as the absolute mean difference between a target knee joint angle and the knee angle reproduced by the subject. Testing was conducted during both partial-weight bearing (PWB) and non-weight bearing (NWB) tasks. Differences in joint position sense between the conditions were evaluated by repeated-measures analysis of variance testing.

Results

Joint position sense error during the stimulation/sleeve condition (2.48° ± 1.32°) was found to be more accurate (P < 0.05) relative to the control condition (3.35° ± 1.63°) in the PWB task. No difference in joint position sense error was found between stimulation/sleeve and sleeve alone conditions for the PWB task. Joint position sense error was not found to differ between any of the conditions for the NWB task.

Conclusion

These results suggest that SR electrical stimulation when combined with a neoprene sleeve is an effective modality for enhancement of joint proprioception in the PWB knee. We believe these results suggest the need for further study of the potential of SR stimulation to correct proprioceptive deficits in a clinical population with knee injury/pathology or in subjects at risk of injury because of a proprioceptive deficit.

Performance in Different Proprioceptive Tests Does Not Correlate in Ankles With Recurrent Sprain

OBJECTIVE

To determine the relation between 2 proprioceptive tests, movement detection and movement discrimination, at the ankle.

DESIGN

A cross-sectional descriptive study.

SETTING

Research laboratory.

PARTICIPANTS

Eighteen subjects with recurrent ankle inversion sprain.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Threshold to detection of movement was tested for inversion and eversion movements at 3 velocities (0.1 degrees , 0.5 degrees , 2.5 degrees /s). Movement discrimination was tested for plantarflexion and inversion movements. The tests were performed in random order, and the velocity and movements were randomized within each test paradigm. Correlations (Pearson r) were calculated between movement detection and movement discrimination.

RESULTS

Correlation within each proprioceptive paradigm was poor to moderate: for movement detection, correlations among movement directions at each velocity ranged from r equal to .53 to r equal to .54; for movement discrimination correlation was r equal to .49. There was poor correlation between the scores for the 2 tasks in 10 of the 12 comparisons (r range, -.02 to -.36).

CONCLUSIONS

These findings show that performance in different proprioceptive tests is not well correlated and, therefore, that general proprioceptive status cannot be inferred from assessment of a single proprioceptive test.

Effect of Rehabilitation on Hip and Knee Proprioception in Older Adults After Hip Fracture

OBJECTIVE

Impaired proprioception may predispose patients with hip fracture to increased risk of future disability. The purpose of the study was to determine the effect of rehabilitation on proprioceptive changes in both the hip and knee joints of patients after hip fracture.

DESIGN

Data were collected on 30 patients with hip fracture (mean age, 79.6 +/- 6.7 yrs) who attended physical and occupational therapy sessions five times per week during a rehabilitation hospital stay of 24.8 +/- 8.1 days. Proprioception was assessed with an electrogoniometer within 48 hrs of admission to and discharge from the rehabilitation unit. The passive-to-active reproduction of joint angle technique determined absolute angular error in non-weight-bearing positions at 15, 30, and 60 degrees of hip flexion and knee extension in both injured and noninjured sides.

RESULTS

Absolute angular error decreased significantly (P < 0.05) from admission (5.3 +/- 2.6 degrees, 4.1+/- 3.1 degrees) to discharge (3.0 +/- 2.3 degrees, 2.8 +/- 3.1 degrees) in hip flexion and knee extension, respectively, on the injured side. Absolute angular error was significantly less (P < 0.05) at 15 degrees compared with 30 and 60 degrees of hip flexion at admission and discharge on the injured side.

CONCLUSIONS

Hip and knee joint proprioception significantly improved in the injured side after the rehabilitation program. This may be an important outcome regarding future disability in this population.

Physiological quadriceps lag: Its nature and clinical significance

A study of the limit of active and passive knee extension in 64 healthy adults revealed a physiological quadriceps lag; that is, in most subjects the active limit of knee extension fell short of the passive limit. With the subjects seated, for the passive test the examiner lifted the heel until the relaxed knee sagged into full extension under its own weight. The active test component comprised maximum active extension held for at least 5 sec. Videotaped reference markers on the lateral aspect of the limb were computer-analysed to derive the active and passive test positions. The active limit of knee extension was less than the passive limit by an average 2.5 degrees at the instant of maximum active knee extension, and by 2.9, 3.5, 4.0, 4.5 and 5.0 degrees 1, 2, 3, 4 and 5 sec later. At 0 and 5 sec, 16% and 41% of the subjects manifested a quadriceps lag of at least 5 degrees. There was no correlation between the magnitudes of passive knee extension and quadriceps lag. Since clinicians typically take several seconds to estimate visually or otherwise measure knee extension, account should be taken of the duration of maximum active contraction, as well as other details of test methodology, if quadriceps lag tests are to produce valid and reliable results.