Marcus B. Stone

Arthrogenic muscle response to a simulated ankle joint effusion

Background: Arthrogenic muscle inhibition (AMI) is a continuing reflex reaction of the musculature surrounding a joint after distension or damage to the structures of that joint. This phenomenon has been well documented after knee joint injury and has been generalised to occur at other joints of the human body, yet minimal research has been conducted in this regard. The response of the muscles crossing the ankle/foot complex after ankle injury and effusion is not well understood. AMI may occur after an ankle sprain contributing to residual dysfunction. Objective: To determine if AMI is present in the soleus, peroneus longus, and tibialis anterior musculature after a simulated ankle joint effusion. Methods: Eight neurologically sound volunteers (mean (SD) age 23 (4) years, height 171 (6) cm, mass 73 (10) kg) participated. Maximum H-reflex and maximum M-wave measurements were collected using surface electromyography after delivery of a percutaneous stimulus to the sciatic nerve before its bifurcation into the common peroneal and posterior tibial nerves. Results: The H-reflex and M-wave measurements in all muscles increased (p⩽0.05) after the simulated ankle joint effusion. Conclusions: Simulated ankle joint effusion results in facilitation of the soleus, peroneus longus, and tibialis anterior motoneurone pools. This may occur to stabilise the foot/ankle complex in order to maintain posture and/or locomotion.

Arthrogenic muscle inhibition is not present in the limb contralateral to a simulated knee joint effusion.

Palmieri RM, Ingersoll CD, Edwards JE, Hoffman MA, Stone MB, Babington JP, Cordova ML, Krause BA: Arthrogenic muscle inhibition is not present in the limb contralateral to a simulated knee joint effusion. Am J Phys Med Rehabil 2003;82:910–916. ObjectiveThe purpose of this investigation was to estimate bilateral neuromuscular activity in the vastus medialis on induction of a unilateral knee joint effusion. DesignEight subjects each were assigned to effusion or control groups. The effusion group had 60 ml of sterile saline injected into their superolateral knee joint capsules. The control group rested for 8 mins. Bilateral recruitment curves for the Hoffmann reflex (H-reflex) and muscle response (M-wave) were obtained before and 10, 20, and 30 mins after the effusion or rest. The maximum H-reflex (Hmax), maximum M-wave (Mmax), and the Hmax/Mmax ratio were utilized for data analysis. ResultsBoth Hmax and Hmax/Mmax ratios decreased from the baseline measure in the effused vastus medialis, whereas no changes were detected on the contralateral side. Effused subjects demonstrated decreased motoneuron pool excitability in the effused limb, whereas control subjects did not differ from baseline. ConclusionsKnee joint effusion results in ipsilateral but not contralateral impairment of quadriceps function. Rehabilitation protocols after knee joint injury should focus on ipsilateral neuromuscular and mechanical alterations that occur as the result of joint damage.

Preliminary comparison of bromelain and Ibuprofen for delayed onset muscle soreness management.

ObjectiveThe purpose of this study was to determine whether a common bromelain regimen or common ibuprofen regimen are effective in resolving pain and muscle dysfunction associated with delayed onset muscle soreness of the elbow flexors. DesignA randomized, double-blinded, repeated measures design was used for this study. SettingThe study was performed in the Sports Injury Research Lab at an NCAA Division I university. ParticipantsForty subjects who had not participated in an upper body resistance-training program 3 months prior to the study, suffered pain or injury in the nondominant arm, or experienced an adverse response to nonsteroidal anti-inflammatory drugs or pineapple (bromelain source) were recruited. Thirty-nine subjects finished the study. InterventionsActive range of motion (ROM), perceived pain, and peak concentric torque measurements of the nondominant arm were taken prior to and 24, 48, 72, and 96 hours following an eccentric exercise protocol of the elbow flexors. Subjects were assigned to one of four treatment groups (bromelain 300 mg t.i.d., ibuprofen 400 mg t.i.d., placebo t.i.d., and control) and began treatment immediately following the exercise protocol. Main Outcome MeasuresNo differences among treatments were observed for any of the dependent variables at any time. ROM deficits and pain peaked between 48 and 72 hours. Peak torque deficiencies were observed between 24 and 72 hours. ConclusionsIngestion of bromelain and ibuprofen had no effect on elbow flexor pain, loss of ROM, or loss of concentric peak torque as a result of an eccentric exercise regimen.

The Effect of a Simulated Knee Joint Effusion on Postural Control in Healthy Subjects

OBJECTIVE To determine the effects of a simulated knee joint effusion on center of pressure (COP) path and mean power frequency (MPF) during standing. DESIGN Quasi-experimental design. SETTING Sports injury research laboratory in a university setting. PARTICIPANTS Twenty healthy volunteers, 10 of whom (age, 20.1+/-2.4y; height, 168.0+/-8.1cm; weight, 70.4+/-13.3kg) were assigned to an effusion group and 10 of whom (age, 25+/-3.8y; height, 169.4+/-8.9cm; weight, 74.7+/-7.7kg) were assigned to a control group. INTERVENTIONS COP data were collected before and after a 60-mL injection of sterile saline into the knee joint space. MAIN OUTCOME MEASURES COP path and mediolateral and anteroposterior MPF. RESULTS COP path decreased after the effusion (pre-effusion mean, 92.2+/-21.9cm; posteffusion mean, 77.27+/-23.0cm). No change was found within the control group for COP path (P>.05). No differences were detected before or after joint effusion when the MPF was examined (P>.05). CONCLUSIONS Possible explanations for the improved postural control after the effusion include additional somatosensory feedback, an augmented neural drive to the soleus, and/or increased capsular tension.

Cryotherapy and ankle bracing effects on peroneus longus response during sudden inversion

Cryotherapy and ankle bracing are often used in conjunction as a treatment for ankle injury. No studies have evaluated the combined effect of these treatments on reflex responses during inversion perturbation. This study examined the combined influence of ankle bracing and joint cooling on peroneus longus (PL) muscle response during ankle inversion. A 2x2 RM factorial design guided this study; the independent variables were: ankle brace condition (lace-up brace, control), and treatment (ice, control), and the dependent variables studied were PL stretch reflex latency (ms), and PL stretch reflex amplitude (% of max). Twenty-four healthy participants completed 5 trials of a sudden inversion perturbation to the ankle/foot complex under each ankle brace and cryotherapy treatment condition. No two-way interaction was observed between ankle brace and treatment conditions on PL latency (P=0.283) and amplitude (P=0.884). The ankle brace condition did not differ from control on PL latency and amplitude. Cooling the ankle joint did not alter PL latency or amplitude compared to the no-ice treatment. Ankle bracing combined with joint cooling does not have a deleterious effect on dynamic ankle joint stabilization during an inversion perturbation in normal subjects.

A SINGLE DOSE OF GINKGO BILOBA DOES NOT AFFECT SOLEUS MOTONEURON POOL EXCITABILITY.

EGb 761 has been shown to increase acetylcholine synthesis and release and increase cholinergic receptors leading to an increase in cholinergic neurotransmission. These effects may be observed in the neuromuscular system, manifested by changes in motoneuron pool excitability as measured by the Hoffmann reflex to motor response (H/M) ratio. The objective was to determine whether a single dose of EGb 761 affects motoneuron pool excitability of the soleus muscle as measured by the H/M ratio. Following initial soleus H/M measurements, 20 healthy volunteers were randomly assigned to 1 of 3 treatment groups (control, 180 g cellulose placebo, and 180 g EGb 761). H/M ratios were recorded 1, 2, and 3 hours post treatment. A 3 × 4 repeated-measures analysis of variance was used to analyze differences in H/M ratio between treatments. No differences were observed between treatments (p = 0.75) or over time (p = 0.17), and there was not a treatment by time interaction (p = 0.27). A single dose of 180 g of EGb 761 does not affect soleus motoneuron pool excitability.