The effects of kinesiophobia on postural control with chronic ankle instability

BACKGROUND

Patients with chronic ankle instability (CAI) often experience injury-related fear following ankle injuries, a condition known as kinesiophobia. Little research has investigated the impact of kinesiophobia in patients with CAI.

RESEARCH QUESTION

How does kinesiophobia impact the static and dynamic balance of individuals with CAI?

METHODS

Fifty patients with CAI were divided into 2 subgroups based on their responses to the Tampa Scale of Kinesiophobia: 25 with kinesiophobia (CAI-K) and 25 without kinesiophobia (CAI-N). These groups were compared to 20 control participants. All participants performed a single-leg balance test with eyes open (EO) and eyes closed (EC). They also performed the Y-balance test (YBT) with EO. Romberg ratios were calculated as EC/EO and used for statistical analysis.

RESULTS

No differences in static balance with EO and EC were found among three groups. However, the CAI-K group displayed a higher Romberg ratio in the mediolateral direction during static balance than both CAI-N and control groups. Additionally, both CAI-K and CAI-N groups displayed higher Romberg ratio in the anterior-posterior than controls. During YBT, the CAI-K group showed reduced reach distance in the anterior direction than CAI-N and control groups.

SIGNIFICANCE

The CAI-K group relies more on visual feedback during static balance in the mediolateral direction than CAI-N and control groups. Furthermore, the CAI-K group displayed less anterior reach distance during YBT compared to the CAI-N and control groups. Clinicians should consider both psychological and physical factors when designing rehabilitation programs.

Effects of anticipation on joint kinematics during inversion perturbation in individuals with chronic ankle instability

BACKGROUND

Although chronic ankle instability (CAI) patients display altered reactive joint kinematics after inversion perturbation, little is known about the effects of anticipation on reactive joint kinematics among CAI, coper, and control groups.

OBJECTIVE

To assess changes in reactive joint kinematics after different inverted landing situations including planned- and unplanned-condition among groups of CAI, coper, and control.

METHODS

Sixty-six volunteers participated (22 per group). Participants completed three trials of both planned and unplanned single-leg landing onto an inverted force platform while reactive joint kinematic data were collected from initial-contact to 200 ms after initial-contact. Two-way repeated measures ANOVAs were used to examine the differences between condition (planned-, unplanned-conditions) and group (CAI, coper, control).

RESULTS

There were significant group by condition interactions for total ankle displacement in the frontal plane (p < 0.01) and maximum ankle inversion velocity (p = 0.01). CAI patients displayed increased ankle displacement (p < 0.01) and maximum inversion velocity (p < 0.01) under the unplanned condition compared to the planned condition. However, copers did not show any differences in ankle displacement and maximum inversion velocity between the two conditions.

CONCLUSIONS

CAI patients displayed greater changes in ankle joint displacement and maximum ankle inversion velocity occurred after inversion perturbation under unplanned condition compared with copers and controls. Current data suggest that altered reactive joint kinematics under the unanticipated condition in CAI patients may contribute to the condition of CAI after ankle sprains. Clinicians should focus on rehabilitation programs to recover and/or develop feedback control for CAI patients during functional movements under unanticipated condition to prevent further injuries.

Acute effects of external visual feedback using cross-line laser on landing neuromechanics and postural control in chronic ankle instability

Although neuromuscular training (NMT) programmes positively enhance clinical deficits in chronic ankle instability (CAI) patients, the effectiveness of NMTs in restoring movement patterns during jump landing is still questionable. Before developing new prolonged motor-learning interventions, it is important to determine the immediate effects of intervention on movement patterns during jump-landing in patients with CAI. Therefore, the purpose of this study was to determine whether real-time external feedback using a crossline laser device changes the movement patterns during jump-landing and balance tasks in patients with CAI. Eighteen patients with CAI completed three successful single-leg jump-landing tasks and single-leg balance tasks under the conditions of with and without external feedback. Lower-extremity joint angles, moments, and EMG activation of six muscles were collected during the single leg jump-landing task and centre of pressure data were collected during the single-leg balance test. Real-time external feedback allowed to change neuromechanical characteristics in the entire lower-extremity (i.e., ankle, knee, and hip joints) during jump-landing. However, there were no differences in static postural control between the two conditions. Clinicians should carefully consider incorporating a cost-effective laser device into an augmented NMT programme of longer duration to improve movement patterns during functional tasks in patients with CAI.

Effects of transcutaneous electrical nerve stimulation on quadriceps function in individuals with experimental knee pain

Knee joint pain (KJP) is a cardinal symptom in knee pathologies, and quadriceps inhibition is commonly observed among KJP patients. Previously, KJP independently reduced quadriceps strength and activation. However, it remains unknown how disinhibitory transcutaneous electrical nerve stimulation (TENS) will affect inhibited quadriceps motor function. This study aimed at examining changes in quadriceps maximum voluntary contraction (MVC) and central activation ratio (CAR) before and after sensory TENS following experimental knee pain. Thirty healthy participants were assigned to either the TENS or placebo groups. All participants underwent three separate data collection sessions consisting of two saline infusions and one no infusion control in a crossover design. TENS or placebo treatment was administered to each group for 20 min. Quadriceps MVC and CAR were measured at baseline, infusion, treatment, and post-treatment. Perceived knee pain intensity was measured on a 100-mm visual analogue scale. Post-hoc analysis revealed that hypertonic saline infusion significantly reduced the quadriceps MVC and CAR compared with control sessions (P < 0.05). Sensory TENS, however, significantly restored inhibited quadriceps motor function compared with placebo treatment (P < 0.05). There was a negative correlation between changes in MVC and knee pain (r = 0.33, P < 0.001), and CAR and knee pain (r = 0.62, P < 0.001), respectively.

The influence of experimental anterior knee pain during running on electromyography and articular cartilage metabolism

OBJECTIVE

To determine whether anterior knee pain (AKP), during running, acutely affects lower-extremity electromyography (EMG) and articular cartilage metabolism.

METHODS

A within-subjects design was used. Each of 12 able-bodied subjects ran on a treadmill for 30 min for three different sessions: control (no infusion), sham (0.9% NaCl infusion into the involved-leg infrapatellar fat pad), and pain (5.0% NaCl infusion into the involved-leg infrapatellar fat pad). Bilateral surface EMG was monitored for the vastus medialis (VM), vastus lateralis (VL), and gastrocnemius (GA). Serum cartilage oligomeric matrix protein (COMP) concentration was determined before, after, and 60 min after the run. A functional analysis approach was used to compare EMG amplitude, across the entire stance phase, between sessions and legs. Mixed-model analysis of covariance was used to compare serum COMP concentration between sessions, across time.

RESULTS

Relative to the uninvolved leg, greater involved-leg VL and GA EMG amplitude existed during midstance for the sham and control sessions (P < 0.01). During the painful session, however, involved-leg VM, VL, and GA EMG amplitude was 5-10% less than for the uninvolved leg. COMP concentration immediately post-run was 14% and 21% greater than pre-run (P = 0.01) and 60 min post-run concentrations (P < 0.01), respectively. Session, however, did not significantly influence COMP.

CONCLUSION

During a 30-min run, AKP acutely alters midstance VM, VL, and GA EMG amplitude. AKP during a 30-min run does not, however, acutely influence articular cartilage metabolism.

Effect of knee joint effusion on quadriceps and soleus motoneuron pool excitability

PURPOSE

To examine changes in quadriceps and soleus MN pool activity resulting from knee joint effusion over a 4-h period and assess the relationship between the muscles.

METHODS

A repeated measures before-after trial design was used for this study. Eight, neurologically sound volunteers (age 23.3+/-2.1 yr, height 171.8+/-15.9 cm, mass 65.5+/-17.7 kg) participated in this study. An area superomedial to the patella was cleaned and anesthetized, and 30 mL of sterile saline was injected into the knee joint capsule to mimic mechanical joint effusion. The Hoffman reflex (H-reflex) was elicited by applying a percutaneous stimulus to the appropriate nerve and recording the response through surface electromyography. Soleus and vastus medialis H-reflex measures were collected from each volunteer before, at 30 min, 90 min, 150 min, and 210 min intervals over a 4-h period after knee effusion.

RESULTS

All soleus H-reflex measures after effusion (30 min 5.89+/-0.92 V; 90 min 6.16+/-0.48 V; 150 min 6.59+/-0.50 V; 210 min 6.70+/-0.56 V) were increased in relation to the preeffusion measure (5.01+/-0.79 V). All vastus medialis H-reflex measures after effusion (30 min 4.23+/-0.94 V; 90 min 4.15 +/-1.11 V; 150 min 4.16+/-0.57 V; and 210 min 4.99+/-1.23) were decreased in relation to the preeffusion measure (5.88+/-1.44 V; P < or = 0.05).

CONCLUSIONS

Afferent activity from the knee joint capsule resulted in an inhibitory effect on the vastus medialis and a facilitatory effect on the soleus. Facilitation of the soleus in cooperation with other lower extremity musculature could be a mechanism for compensation of the inhibited quadriceps to maintain lower kinetic chain function.

Changes in soleus motoneuron pool excitability after artificial knee joint effusion

OBJECTIVE

To compare changes in the magnitude of soleus motoneuron excitability before and over a 4-hour period following artificial knee effusion.

DESIGN

Before-after trial.

SETTING

All measurements were collected in the Sports Injury Research Laboratory, Indiana State University.

PARTICIPANTS

Eleven healthy and neurologically sound volunteers (mean age +/- SD, 24 +/- 3yr; height, 173.2 +/- 9.6cm; weight, 72.9 +/- 8.7kg) with no history of lower-extremity surgery and no lower extremity pathology in the last year.

INTERVENTIONS

An area superolateral to the patella was cleaned and injected subcutaneously with 2mL of lidocaine for anesthetic purposes. With a second disposable syringe, 25mL of sterile saline was injected through the superolateral knee joint capsule into the joint space to mimic mechanical joint effusion.

MAIN OUTCOME MEASURE

Hoffmann's reflex (H-reflex) was elicited by applying a percutaneous stimulus to the tibial nerve in the popliteal fossa. Seven to 12 stimuli were delivered at 20-second intervals with varying intensities to find the maximal H-reflex. The maximal H-reflex was measured five times at the same stimulus intensity with 20-second rest intervals. This measurement was recorded before injection and at 1-hour intervals following the injection for 4 hours.

RESULTS

An overall difference between groups was found. Measurements from hours 3 and 4 were significantly higher than the preinjection measurements (p < or = .05).

CONCLUSIONS

The soleus motoneuron pool was not inhibited as expected. The soleus was facilitated beyond the preinjection level, showing that the quadriceps and soleus do not respond in the same way to artificial knee effusion. Because the quadriceps are normally inhibited during knee effusion, this facilitation could be the result of a compensatory reaction by the soleus in response to inhibited quadriceps. Further studies must be performed to determine the extent and duration of soleus motoneuron pool excitability in relation to quadriceps inhibition elicited by artificial knee effusion.

Intrasession and intersession reliability of the soleus H-reflex in supine and standing positions

The Hoffmann reflex (H-reflex) is a measure of motoneuron pool excitability, which is valuable in determining muscle inhibition caused by joint damage (arthrogenic muscle inhibition). In order to detect changes in H-reflex due to injury, the reliability of such a measurement must be established. The purpose of this study was to establish the intrasession and intersession reliability of soleus H-reflex in a supine and standing position. Thirteen healthy volunteers (age 10 +/- 2.63 yr, height 171.35 +/- 10.19 cm, mass 69.62 +/- 13.03 Kg) with no lower extremity orthopedic or neurological disorders within the past year participated in this study. To determine the intrasession and intersession reliability of this measure in a supine resting position and a one-leg standing position, EMG data were collected from the soleus while the tibial nerve was stimulated in the popliteal space. A high voltage (120-200 V), short duration (1.0 msec) stimulus was automatically triggered, eliciting a reflex twitch detected by surface EMG. Several of these measurements were performed with 20 second rest intervals to find the maximum H-reflex. The maximum H-reflex was located by adjusting the intensity of the stimulus. Once a maximum H-reflex was found, 12 measurements were taken in that position with 20 second rest intervals. These steps were repeated for each position (supine and standing) at the same time for 5 consecutive days. Intrasession reliability was computed using 12 measurement trials (12), 12 measurement trials dropping the high and low score (12x), the first 7 measurement trials dropping the high and low score (7x), and the first 5 measurement trials (5). Intrasession and intersession reliability over five consecutive days was estimated using intraclass correlation coefficients (ICC (3, 1)). The supine intrasession reliability measurements were as follows: 0.932 (12), 0.932 (12x), 0.935 (7x), and 0.932 (5). The standing intrasession reliability was 0.853 (12), 0.852 (12x), 0.865 (7x), and 0.862 (5). The intersession reliability was 0.938 in the supine position and 0.803 in the standing position. These results indicate that the H-reflex measured using our protocol in a supine and standing position is a reliable assessment within sessions and between sessions. Five measurements are sufficient to observe reliable measurements within a single session. Most importantly, this data shows that the H-reflex is a reliable assessment that may be used to measure small changes in motoneuron pool excitability over time.

An electromyographic comparison of 4 closed chain exercises

OBJECTIVE

Closed chain exercises are used in the clinical setting to safely strengthen the muscles about the knee. We compared the EMG activity of 3 muscles (vastus lateralis, vastus medialis, and biceps femoris) during 4 closed chain exercises (unilateral one-quarter squat, lateral step-up, FlexCord front pull, and FlexCord back pull) to determine which exercise produced the most muscle activity.

DESIGN AND SETTING

We used a 4 x 3 x 2 factorial design with repeated measures on exercise, muscle, and movement (knee flexion and extension). Muscle and movement were the control variables for post hoc comparisons. Data were collected in a sports injury research laboratory.

SUBJECTS

Thirty-eight healthy, active female college students aged 21.97 +/- 2.8 years, with height 166.9 +/- 6.3 cm and weight 61.9 +/- 8.5 kg. Subjects had no history of lower extremity pathology that resulted in surgery and no lower extremity pathology within the last year.

MEASUREMENTS

We placed surface electrodes on the vastus lateralis, vastus medialis, and biceps femoris muscles. Synchronized with a metronome, subjects performed 3 repetitions of 4 exercises between 5 degrees and 30 degrees of knee flexion. Electromyographic measurements were taken from the middle third of the flexion and extension phase of each repetition.

RESULTS

The FlexCord front pull and back pull produced higher levels of biceps femoris activity than the quarter squat and step-up. The FlexCord front pull also produced a higher level of vastus medialis activity during knee extension than the quarter squat, lateral step-up, or FlexCord back pull.

CONCLUSIONS

The high levels of biceps femoris activity during the FlexCord exercises indicate that a greater cocontraction exists. With a greater cocontraction, the FlexCord exercises could be safely used during ACL rehabilitation. The high levels of vastus medialis activity during the FlexCord front pull suggest that it may be a beneficial exercise for patellofemoral rehabilitation.

Interventional cardiology in the mid-1990s: maturation of the technique and results from the Medical Center of Delaware

Coronary angioplasty has continued to evolve and mature and is now used in an increasing array of coronary lesions in an ever-broadening selection of patients. Although the patients treated have continually been sicker and those with more advanced disease, the clinical results of this procedure have continued to improve. This, combined with carefully controlled studies that show a near equivalence of multivessel angioplasty and bypass surgery in selected patients, ensure that coronary angioplasty will continue to play an important role in coronary revascularization in the future.