Susan A. Saliba

Immediate Effects of Transcutaneous Electrical Nerve Stimulation and Focal Knee Joint Cooling on Quadriceps Activation

PURPOSE To determine whether transcutaneous electrical nerve stimulation (TENS) and focal knee joint cooling will affect the quadriceps central activation ratio (CAR) in patients with tibiofemoral osteoarthritis. METHODS Thirty-three participants with diagnosed tibiofemoral osteoarthritis were randomly allocated to the 45-min TENS treatment (six males and four females, 56 +/- 10.1 yr, 174.11 +/- 10.78 cm, 89.34 +/- 21.3 kg), the 20-min focal knee joint cooling treatment (six males and five females, 58 +/- 8.4 yr, 176.41 +/- 8.29 cm, 83.18 +/- 17.97 kg), or the control group (five males and seven females, 54 +/- 9.9 yr, 166.37 +/- 13.07 cm, 92.14 +/- 25.37 kg). Volitional quadriceps activation, maximal voluntary isometric contraction, and subjective pain measurements were conducted at baseline and at 20, 30, and 45 min. The 20-min focal knee joint cooling intervention consisted of two 1.5-L ice bags to the anterior and posterior aspects of the knee. The TENS group received 45 min of a sensory, biphasic square wave stimulation (150-mus phase duration and 150 pps) from four 2 x 2-inch electrodes positioned around the patella. RESULTS : TENS resulted in a significantly higher percent change in CAR scores compared with control at 20 min (6.4 +/- 4.8 vs -3.5 +/- 8, P = 0.006), 30 min (9.7 +/- 10.16 vs -1 +/- 7.9, P = 0.025), and 45 min (11.25 +/- 6.96 vs 0.81 +/- 9.4, P = 0.029). Focal knee joint cooling resulted in significantly higher percent change scores compared with the control group at 20 min (5.75 +/- 7.25 vs -3.5 +/- 8, P = 0.009) and trended to be higher at 45 min (9.06 +/- 9.63 vs 0.81 +/- 9.4, P = 0.098). No significant differences in percent change for CAR were found between the TENS and the focal knee joint cooling group. CONCLUSIONS Both TENS and focal knee joint cooling increased the quadriceps CAR immediately after application in participants with tibiofemoral osteoarthritis.

Effects of Neuromuscular Electrical Stimulation After Anterior Cruciate Ligament Reconstruction on Quadriceps Strength, Function, and Patient-Oriented Outcomes: A Systematic Review

STUDY DESIGN Systematic literature review. OBJECTIVE To perform a systematic review of randomized controlled trials assessing the effects of neuromuscular electrical stimulation (NMES) on quadriceps strength, functional performance, and self-reported function after anterior cruciate ligament reconstruction. BACKGROUND Conflicting evidence exists regarding the effectiveness of NMES following anterior cruciate ligament reconstruction. METHODS Searches were performed for randomized controlled trials using electronic databases from 1966 through October 2008. Methodological quality was assessed using the Physiotherapy Evidence Database Scale. Between-group effect sizes and 95% confidence intervals (CIs) were calculated. RESULTS Eight randomized controlled trials were included. The average Physiotherapy Evidence Database Scale score was 4 out of possible maximum 10. The effect sizes for quadriceps strength measures (isometric or isokinetic torque) from 7 studies ranged from -0.74 to 3.81 at approximately 6 weeks postoperatively; 6 of 11 comparisons were statistically significant, with strength benefits favoring NMES treatment. The effect sizes for functional performance measures from 1 study ranged from 0.07 to 0.64 at 6 weeks postoperatively; none of 3 comparisons were statistically significant, and the effect sizes for self-reported function measures from 1 study were 0.66 and 0.72 at 12 to 16 weeks postoperatively; both comparisons were statistically significant, with benefits favoring NMES treatment. CONCLUSION NMES combined with exercise may be more effective in improving quadriceps strength than exercise alone, whereas its effect on functional performance and patient-oriented outcomes is inconclusive. Inconsistencies were noted in the NMES parameters and application of NMES. LEVEL OF EVIDENCE Therapy, level 1a-.

Effects of Transcutaneous Electrical Nerve Stimulation and Therapeutic Exercise on Quadriceps Activation in People With Tibiofemoral Osteoarthritis

STUDY DESIGN Blinded, randomized controlled trial. OBJECTIVES To determine if the combination of transcutaneous electrical nerve stimulation (TENS) set to a sensory level and therapeutic exercise would be more effective than the combination of placebo TENS and therapeutic exercises or therapeutic exercises only to increase quadriceps activation in individuals with tibiofemoral osteoarthritis. BACKGROUND Quadriceps activation deficits are common in those with tibiofemoral osteoarthritis, and TENS has been reported to immediately increase quadriceps activation. Yet the long-term benefits of TENS for motor neuron activation have yet to be determined. METHODS Thirty-six individuals with radiographically assessed tibiofemoral osteoarthritis were randomly assigned to the TENS and exercise, placebo and exercise, and exercise only groups. All participants completed a supervised 4-week lower extremity exercise program. TENS and placebo TENS were worn throughout the therapeutic exercise sessions, as well as during daily activities. Our primary outcome measures, quadriceps central activation ratio, and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) were evaluated at baseline and at 2 weeks and 4 weeks of the intervention. RESULTS Quadriceps activation was significantly higher in the TENS with exercise group compared to the exercise only group at 2 weeks (0.94 ± 0.04 versus 0.82 ± 0.12, P<.05) and the placebo and exercise group at 4 weeks (0.94 ± 0.06 versus 0.81 ± 0.15, P<.05). WOMAC scores improved in all 3 groups over time, with no significant differences among groups. CONCLUSION This study provides evidence that TENS applied in conjunction with therapeutic exercise and daily activities increases quadriceps activation in patients with tibiofemoral osteoarthritis and, while function improved for all participants, effects were greatest in the group treated with a combination of TENS and therapeutic exercises. LEVEL OF EVIDENCE Therapy, level 1b-.

Voluntary Quadriceps Activation Deficits in Patients with Tibiofemoral Osteoarthritis: A Meta-Analysis

The objective of this study was to assess the magnitude of quadriceps activation deficits in the involved extremity and contralateral extremity of patients with knee joint osteoarthritis (OA), as well as matched controls. An exhaustive search of the literature was performed using Web of Science between 1970 and February 24, 2010, using the search terms “osteoarthritis” AND “quadriceps activation” OR “quadriceps inhibition” and cross‐referencing pertinent articles. Studies written in English reporting quadriceps activation means and standard deviations in patients with tibiofemoral OA via a method using an exogenous electrical stimulation were evaluated for methodological quality and were included for data analysis. Fourteen individual studies met the criteria for inclusion into data analysis. The number of participants and mean activation levels were used to calculate weighted means for the involved limb (14 studies), the contralateral limb (from a subset of 6 studies), and an involved limb subset from only the studies evaluating the contralateral limb and population of control subjects (5 studies). Weighted means from the involved limb (82.2; 95% CI = 81.4‐83.3%), contralateral limb (81.7; 80.1‐83.3%), and involved limb subset (76.8; 74.8‐78.8%) groups were found to have lower volitional quadriceps activation compared with the control groups (90; 88.9‐91.7%). Although the weighted involved limb mean was not different from that of the contralateral limb, the mean and 95% confidence intervals for the involved limb subset were lower than that of the contralateral limb group, suggesting that the involved limb had less volitional activation within OA subjects. This provides evidence that bilateral quadriceps volitional activation deficits are present in persons with knee OA.

Differences in Lateral Ankle Laxity Measured via Stress Ultrasonography in Individuals With Chronic Ankle Instability, Ankle Sprain Copers, and Healthy Individuals

STUDY DESIGN Cross-sectional. OBJECTIVE To use stress ultrasonography to measure the change in anterior talofibular ligament length during the simulated anterior drawer and ankle inversion stress tests. BACKGROUND In approximately 30% of individuals, ankle sprains may eventually develop into chronic ankle instability (CAI) with recurrent symptoms. Individuals with CAI and those who have a history of ankle sprain (greater than 1 year prior) without chronic instability (copers) may or may not have mechanical laxity. METHODS Sixty subjects (n=60 ankles) were divided into 3 groups: 1) Control subjects without ankle injury history (n=20; mean ± SD age; 24.8 ± 4.8 years; height, 173.7 ± 9.4 cm; weight, 77.2 ± 19.5 kg), ankle sprain copers (n=20; 22.3 ± 2.9 years; 172.8 ± 11.3 cm; 72.4 ± 14.3 kg), and subjects with CAI (n=20; 23.5 ± 4.2 years; 174.6 ± 9.6 cm; 74.8 ± 17.3 kg). Ligament length change with the anterior drawer and end range ankle inversion was calculated from ultrasound images. The Foot and Ankle Ability Measure (FAAM) was used to quantify self-reported function on activities-of-daily living (ADL) and sports. RESULTS The anterior drawer test resulted in length changes that were greater (F₂,₅₇=6.2, P=.004) in the CAI (mean ± SD length change, 15.6 ± 15.1%, P=.006) and the coper groups (14.0 ± 15.9%, P=.016) compared to the control group (1.3 ± 10.7%); however the length change for the CAI and coper groups were not different (P=.93). Ankle inversion similarly resulted in greater ligament length change (F₂,₅₇=6.5, P=.003) in the CAI (25.3 ± 15.5%, P=.003) and coper groups (20.2 ± 19.6%, P=.039) compared to the control group (7.4 ± 12.9%); with no difference in length change between the copers and CAI groups (P=.59). The CAI group had a lower score on the FAAM-ADL (87.4 ± 13.4%) and FAAM-Sports (74.2 ± 17.8%) when compared to the control (98.8 ± 2.9% and 98.9 ± 3.1%, P<.0001) and coper groups (99.4 ± 1.8% and 94.6 ± 8.8%, P<.0001). CONCLUSION Stress ultrasonography identified greater length changes of the anterior talofibular ligament in both the coper and CAI groups compared to the control group. Only subjects with CAI had reductions in self-reported function.

Differential ability of selected postural-control measures in the prediction of chronic ankle instability status.

CONTEXT Chronic ankle instability (CAl) is a term used to identify a condition associated with recurrent ankle sprains and persistent symptoms. Balance deficits, evaluated using center-of-pressure (COP) force-plate measurements, have been shown to occur in people with CAl. OBJECTIVE To determine the differential abilities of selected force-plate postural-control measures to assess CAl. DESIGN Case-control study. SETTING Laboratory. PATIENTS OR OTHER PARTICIPANTS A total of 63 individuals with CAl (30 men, 33 women: age= 22.3± 3.7 years, height= 169.8 ±9.6 cm, mass= 70.7± 14.3 kg) and 46 healthy controls (22 men, 24 women: age= 21.2± 4.1 years, height= 173.3± 9.2 cm, mass =69.2± 13.2 kg) volunteered. INTERVENTION(S) Participants performed 3 10-second trials of quiet, single-limb stance on a force plate under 2 conditions: eyes open and eyes closed. MAIN OUTCOME MEASURE(S) Measures of COP area, COP velocity, COP SO, COP range of excursion, percentage of COP range used, time-to-boundary absolute minimum, time-to-boundary mean of the minima, and time-to-boundary SO of the minima were calculated. All measures with the exception of COP area were calculated in both the mediolateral (ML) and anteroposterior directions. For each measure, a receiver operator curve analysis was created, and the corresponding area under the curve was tested. The optimal diagnostic threshold value for each measure was determined, and the corresponding positive and negative likelihood ratios were calculated. RESULTS Three eyes-closed, single-limb force-plate measures (COP ML SO, ML percentage of COP range used, and time-to-boundary absolute minimum) predicted CAl status. However, all 3 measures had positive likelihood ratios associated with only small shifts in the probability of a patient with a positive test having CAl and negative likelihood ratios associated with very small shifts in the probability of a patient with a negative test not having CAl. CONCLUSIONS No single force-plate measure was very effective in predicting if an individual had CAl or not.

Reliability of thoracic spine rotation range-of-motion measurements in healthy adults.

CONTEXT The reliability of clinical techniques to quantify thoracic spine rotation range of motion (ROM) has not been evaluated. OBJECTIVE To determine the intratester and intertester reliability of 5 thoracic rotation measurement techniques. DESIGN Descriptive laboratory study. SETTING University research laboratory. PATIENTS OR OTHER PARTICIPANTS Forty-six healthy volunteers (age = 23.6 ± 4.3 years, height = 171.0 ± 9.6 cm, mass = 71.4 ± 16.7 kg). MAIN OUTCOME MEASURE(S) We tested 5 thoracic rotation ROM techniques over 2 days: seated rotation (bar in back and front), half-kneeling rotation (bar in back and front), and lumbar-locked rotation. On day 1, 2 examiners obtained 2 sets of measurements (sessions 1, 2) to determine the within-session intertester reliability and within-day intratester reliability. A single examiner obtained measurements on day 2 (session 3) to determine the intratester reliability between days. Each technique was performed 3 times per side, and averages were used for data analysis. Reliability was determined using intraclass correlation coefficients, standard error of measurement (SEM), and minimal detectable change (MDC). Differences between raters during session 1 were determined using paired t tests. RESULTS Within-session intertester reliability estimates ranged from 0.85 to 0.94. Ranges for the SEM were 1.0° to 2.3° and for the MDC were 2.8° to 6.3°. No differences were seen between examiners during session 1 for seated rotation (bar in front, both sides), half-kneeling rotation (bar in front, left side), or the lumbar locked position (both sides) (all values of P > .05). Within-day intratester reliability estimates ranged from 0.86 to 0.95. Ranges for the SEM were 0.8° to 2.1° and for the MDC were 2.1 ° to 5.9°. Between-days intratester reliability estimates ranged from 0.84 to 0.91. Ranges for the SEM were 1.4° to 2.0° and for the MDC were 3.9° to 5.6°. CONCLUSIONS All techniques had good reliability and low levels of measurement error. The seated rotation, bar in front, and lumbar-locked rotation tests may be used reliably when more than 1 examiner is obtaining measurements.

Persistent Neuromuscular and Corticomotor Quadriceps Asymmetry After Anterior Cruciate Ligament Reconstruction

CONTEXT Return to activity in the presence of quadriceps dysfunction may predispose individuals with anterior cruciate ligament reconstruction (ACLR) to long-term joint degeneration. Asymmetry may manifest during movement and result in altered knee-joint-loading patterns; however, the underlying neurophysiologic mechanisms remain unclear. OBJECTIVE To compare limb symmetry of quadriceps neuromuscular function between participants with ACLR and participants serving as healthy controls. DESIGN Descriptive laboratory study. SETTING Research laboratory. PATIENTS OR OTHER PARTICIPANTS A total of 22 individuals with ACLR (12 men, 10 women) and 24 individuals serving as healthy controls (12 men, 12 women). MAIN OUTCOME MEASURE(S) Normalized knee-extension maximal voluntary isometric contraction (MVIC) torque (Nm/kg), quadriceps central activation ratio (CAR) (%), quadriceps motor-neuron-pool excitability (Hoffmann reflex to motor wave ratio), and quadriceps active motor threshold (AMT) (% 2.0 T) were measured bilaterally and used to calculate limb symmetry indices for comparison between groups. We used analyses of variance to compare quadriceps Hoffmann reflex to motor wave ratio, normalized knee-extension MVIC torque, quadriceps CAR, and quadriceps AMT between groups and limbs. RESULTS The ACLR group exhibited greater asymmetry in knee-extension MVIC torque (ACLR group = 0.85 ± 0.21, healthy group = 0.97 ± 0.14; t44 = 2.26, P = .03), quadriceps CAR (ACLR group = 0.94 ± 0.11, healthy group = 1.00 ± 0.08; t44 = 2.22, P = .04), and quadriceps AMT (ACLR group = 1.13 ± 0.18, healthy group = 1.02 ± 0.11; t34 = -2.46, P = .04) than the healthy control group. CONCLUSIONS Asymmetries in measures of quadriceps function and cortical excitability were present in patients with ACLR. Asymmetry in quadriceps strength, activation, and cortical excitability persisted in individuals with ACLR beyond return to recreational activity. Measuring the magnitude of asymmetry after ACLR represents an important step in understanding long-term reductions in self-reported function and increased rate of subsequent joint injury in otherwise healthy, active individuals after ACLR.

Short-term effect of muscle energy technique on pain in individuals with non-specific lumbopelvic pain: a pilot study.

Abstract Muscle energy technique (MET) is a form of manual therapy frequently used to correct lumbopelvic pain (LPP), herein the patient voluntarily contracts specific muscles against the resistance of the clinician. Studies on MET regarding magnitude and duration of effectiveness are limited. This study was a randomized controlled trial in which 20 subjects with self-reported LPP were randomized into two groups (MET or control) after magnitude of pain was determined. MET of the hamstrings and iliopsoas consisted of four 5-second hold/relax periods, while the control group received a sham treatment. Tests for current and worst pain, and pain with provocation were administered at baseline, immediately following intervention and 24 hours after intervention. Separate 2x3 ANOVAs were used to assess results as change scores. Visual analog score (VAS) for worst pain reported in the past 24 hours decreased for the MET group (4.3mm±19.9, p=.03) and increased for the sham (control) group (17.1mm±21.2, p=.03). Subjects receiving MET demonstrated a decrease in VAS worst pain over the past 24 hours, thereby suggesting that MET may be useful to decrease LPP over 24 hours.

Comparison of Hamstring Strain Injury Rates Between Male and Female Intercollegiate Soccer Athletes

Background: Hamstring strains are common among soccer athletes, and they have a high incidence of recurrence. Among American collegiate soccer players, men have an overall higher incidence rate of hamstring strains than women. Purpose: This research compares the hamstring strain injury rates in event and athlete characteristics between male and female college soccer athletes. Study Design: Descriptive epidemiology study. Methods: Data describing partial and complete hamstring strains were obtained from the National Collegiate Athletic Association (NCAA) Injury Surveillance System (ISS) for men’s and women’s soccer from 2004 to 2009. Incidence rate ratios (IRRs) comparing the incidence of hamstring strains between the sexes as well as during games versus practices and the preseason versus the in-season were calculated. χ2 tests were used to compare the occurrence of hamstring strains across different event and athlete characteristics. Results: Men were 64% more likely than women to sustain a hamstring strain (IRR, 1.64; 95% CI, 1.37-1.96). Men had significantly higher rates of hamstring strains than women during both games (IRR, 2.42; 95% CI, 1.82-3.23) and practices (IRR, 1.34; 95% CI, 1.06-1.68). There were no differences between men and women in injury rates during the preseason, but men were significantly more likely to sustain a hamstring strain during the in-season (IRR, 1.98; 95% CI, 1.56-2.52). Men had a significantly higher proportion of recurrent hamstring strains compared with women (men, 22%; women, 12%; P = .003). There were no significant differences in the distribution of strains in event or athlete characteristics between men and women for first-time or recurrent hamstring strains. Conclusion: In collegiate soccer, men have significantly higher rates of hamstring strains than women, and regardless of the recurrence status, the event and athlete characteristics were similar for both sexes. Identifying common characteristics may assist in the targeted development of preventive and rehabilitative programs as well as continued research on hamstring strains among collegiate soccer players.