Journal of Sport Rehabilitation

Alterations in corticomotor excitability are observed in a variety of patient populations, including the musculature surrounding the knee and ankle following joint injury. Active motor threshold (AMT) and motor evoked potential amplitudes (MEPs) elicited through transcranial magnetic stimulation (TMS) are outcomes measures used to assess corticomotor excitability, and have been deemed reliable in upper extremity musculature. However, there are few studies assessing the reliability of TMS measures in lower extremity musculature. Determine the intersession reliability of AMT and MEP amplitudes over 14 and 28 days in the quadriceps and fibularis longus (FL). Descriptive Laboratory Study. University Laboratory PARTICIPANTS: 20 able-bodied volunteers (10M/10F; 22.35 ± 2.3 years; 1.71 ± 0.11m; 73.61 ± 16.77kg). AMT and MEP amplitudes were evaluated at 95, 100, 105, 110, 120, 130, and 140% of AMT in the dominant and non-dominant quadriceps and FL. Interclass Correlation Coefficients (ICCs) were used to assess reliability for absolute agreement and internal consistency between baseline and two follow-up sessions at 14 and 28 days post baseline. Each ICC was fit with the best-fit straight-line or parabola in order to smooth out noise in the observations and best determine if a pattern existed in determining the most reliable MEP value. All muscles yielded strong ICCs between baseline and both time points for AMT. MEPs in both the quadriceps and FL produced varying degrees of reliability, with the greatest reliability demonstrated on day 28 at 130 and 140% of AMT in the quadriceps and FL, respectively. The dominant FL muscle showed a significant pattern as TMS intensity increased MEP reliability increased. TMS can be used to reliably identify corticomotor alterations following therapeutic interventions as well as monitor disease progression.

The postgenomic era and heightened public expectations for tangible improvements in the public health have stimulated a complete transformation of the nation's biomedical research enterprise. The National Institutes of Health (NIH) "Roadmap for Medical Research" has catalyzed this transformation. The NIH roadmap consists of several interrelated initiatives, of which the Clinical and Translational Science Award (CTSA) program is the most relevant for rehabilitation specialists. This article reviews the evolution of this transformation and highlights the unprecedented opportunities the CTSA program provides rehabilitation specialists to play leadership roles in improving the clinical care of their patients.

Abnormal scapular kinematics during throwing motion in baseball players with shoulder disorders has not yet been clarified, although altered scapular position has been suggested to be associated with shoulder disorder. The purpose of this study was to determine if the shoulders of baseball players with throwing disorders demonstrate abnormal scapular kinematics during the simulated arm cocking phase of throwing activity. Cross-sectional study. Laboratory. Eleven baseball players (age: 21.1±1.2 years) with a unilateral shoulder disorder volunteered to participate, including nine players at the collegiate level and two at the adult level. The mean playing experience was 12.1±2.7 years. Scapular upward/downward rotation, posterior/anterior tilting, and external/internal rotation during simulated arm cocking motion were analyzed using a 3D-to-2D registration technique. Scapular external rotation in the throwing shoulder was significantly smaller by 2.0-6.0° compared with that of the contralateral shoulder. There were no detectable differences in scapular upward-downward rotation or anterior-posterior tilting between the throwing and contralateral shoulders. Compared to that in the contralateral shoulder, scapular external rotation was smaller in the throwing shoulders, which would increase the glenohumeral horizontal abduction during the arm cocking phase and be related to the throwing shoulder disorder.

Soft-tissue injuries are commonly treated with ice or menthol gels. Few studies have compared the effects of these treatments on blood flow and muscle strength. To compare blood flow and muscle strength in the forearm after an application of ice or menthol gel or no treatment. Repeated measures design in which blood-flow and muscle-strength data were collected from subjects under 3 treatment conditions. Exercise physiology laboratory. 17 healthy adults with no impediment to the blood flow or strength in their right arm, recruited through word of mouth. Three separate treatment conditions were randomly applied topically to the right forearm: no treatment, 0.5 kg of ice, or 3.5 mL of 3.5% menthol gel. To avoid injury ice was only applied for 20 min. At each data-collection session blood flow (mL/min) of the right radial artery was determined at baseline before any treatment and then at 5, 10, 15, and 20 min after treatment using Doppler ultrasound. Muscle strength was assessed as maximum isokinetic flexion and extension of the wrist at 30°/s 20, 25, and 30 min after treatment. The menthol gel reduced (-42%, P < .05) blood flow in the radial artery 5 min after application but not at 10, 15, or 20 min after application. Ice reduced (-48%, P < .05) blood flow in the radial artery only after 20 min of application. After 15 min of the control condition blood flow increased (83%, P < .05) from baseline measures. After the removal of ice, wrist-extension strength did not increase per repeated strength assessment as it did during the control condition (9-11%, P < .05) and menthol-gel intervention (8%, P < .05). Menthol has a fast-acting, short-lived effect of reducing blood flow. Ice reduces blood flow after a prolonged duration. Muscle strength appears to be inhibited after ice application.

Valid patient-based outcome instruments are necessary for comprehensive patient care that focuses on all aspects of health, from impairments to participation restrictions. To validate the Slovenian translation of Medical Outcome Survey (MOS) Short Form Health Survey (SF-36) and to assess relations among various knee measurements, activity tested with Oxford Knee Score (OKS) and health-related quality of life as estimated with SF-36 domains. Descriptive validation study. Isokinetic laboratory in outpatient rehabilitation unit. 101 subjects after unilateral sport knee injury. All subjects completed the SF-36 and OKS, and isokinetic knee-muscle strength output at 60°/s was determined in 78 participants. Within a 3-d period, 43 subjects completed the SF-36 and OKS questionnaires again. Reliability testing included internal consistency and test-retest reliability. Correlations between SF-36 subscales and OKS were calculated to assess construct validity, and correlation between SF-36 subscales and muscle strength was calculated to assess concurrent validity. Chronbach α was above .78 for all SF-36 subscales. ICCs ranged from .80 to .93. The correlation between OKS and the physical-functioning subscale, showing convergent construct validity, was higher (r = .83, P < .01) than between OKS and mental health (r = .50, P < .01), showing divergent construct validity. Knee-extensor weakness negatively correlated with physical-functioning (r = -.59, P < .01) and social-functioning (r = -.43, P < .01) subscales. The Slovenian translation of the SF-36 is a reliable and valuable tool. The relationships between knee-muscle strength and activity and between knee-muscle strength and SF-36 subscales in patients after sport knee injury were established.

Lower extremity injury is prevalent among individuals participating in sports. Numerous variables have been reported as predisposing risk factors to injury; however, the effects of muscle fatigue on landing kinetics are unclear. To investigate the effects of a single session of repeated muscle fatigue on peak vertical ground-reaction force (GRF) during drop landings. Mixed factorial with repeated measures. Controlled laboratory. 10 female and 10 male healthy recreational athletes. Subjects performed 3 fatigued drop landings (60 cm) after four 20-s Wingate anaerobic tests (WATs) with 5 min of active recovery between fatigued conditions. Kinetic data of peak forefoot (F1) force, peak rear-foot (F2) force, and anteroposterior (AP) and mediolateral (ML) forces at both F1 and F2. A significant main effect was observed in the nonfatigued and fatigued drop landings in respect to peak F2 force. The greatest significant difference was shown between the first fatigued drop-landing condition and the last fatigued drop-landing condition. No significant difference was observed between genders for all GRF variables across fatigue conditions. A single session of repeated conditions of anaerobic muscle fatigue induced by WATs caused an initial reduction in peak F2 force followed by an increase in peak F2 force across conditions. Muscle fatigue consequently alters landing kinetics, potentially increasing the risk of injury.

CONTEXT: Hamstring muscle length is commonly measured because of its perceived relationship to injury of both the hamstrings themselves and also the pelvis and lumbar spine. The popliteal (knee extension) angle measured from the starting position hip and knee at 90° is a commonly used indirect measure of hamstring muscle length. When this measure has been undertaken in the literature previously little attention has been paid to the position of the pelvis, which may significantly influence measurements taken. DESIGN: repeated measures SETTING: University Human Performance laboratory. PARTICIPANTS: 60 healthy physically active males (mean age 20.1+/-1.8 years, range 18-24 years). INTERVENTION: Effect of the two extremes of pelvic position (anterior and posterior) on hamstring muscle length (popliteal angle). MAIN OUTCOME MEASURE: Popliteal angle (with maximal knee extension) was measured in two positions one of full anterior and one of full posterior pelvic tilt. RESULTS: The mean difference in popliteal angle between anterior to posterior pelvic positions was 13.4+/-9° (range 0-26°) this was statistically significant (p=0.0001). CONCLUSION: The findings of the study indicate pelvic position has a significant effect on popliteal angle and therefore should be taken into account when measuring hamstring muscle length.

Context Hamstring muscle length is commonly measured because of its perceived relationship to injury of both the hamstrings themselves and the pelvis and lumbar spine. The popliteal (knee-extension) angle measured from the starting position hip and knee at 90° is a commonly used indirect measure of hamstring muscle length. When this measure has been undertaken in the literature previously, little attention was paid to the position of the pelvis, which may significantly influence measurements taken. Design Repeated-measures. Setting University human performance laboratory. Participants 60 healthy physically active males (mean age 20.1 ± 1.8 y, range 18–24 y). Intervention The 2 extremes of pelvic position (anterior and posterior). Main Outcome Measure Popliteal angle (with maximal knee extension) was measured in 2 positions, 1 of full anterior and 1 of full posterior pelvic tilt. Results The mean difference in popliteal angle between anterior to posterior pelvic positions was 13.4° ± 9° (range 0–26°); this was statistically significant ( P = .0001). Conclusion The findings of the study indicate that pelvic position has a significant effect on popliteal angle and therefore should be taken into account when measuring hamstring muscle length.

Transient abdominal pain commonly occurs during running. There is limited information to guide the physical examination and treatment of individuals with this transient pain with running (TAPR). The purposes of this report are to describe the movement-system examination, diagnosis, and treatment of 2 female adolescent athletes with TAPR and highlight the differences in their treatment based on specific movement impairments. Case series. The movement diagnosis determined for both patients was thoracic flexion with rotation. The key signs and symptoms that supported this diagnosis included (1) alignment impairments of thoracic flexion and posterior sway and ribcage asymmetry; (2) movement impairments during testing and running of asymmetrical range of motion for trunk rotation, side bending, and flexion of the thoracic spine; and (3) reproduction of TAPR. Musculoskeletal impairments related to the trunk muscles combined with the mechanical stresses of running could contribute to TAPR. Treatment in each of the patients was focused on patient education regarding correction of alignment, muscle, and movement impairments of the extremities, thoracic spine, and ribcage. A strategy was determined for correcting motion during running to reduce or abolish the TAPR. Outcomes were positive in both patients. Differences in specific impairments in each patient demonstrate the need for specificity of treatment. These 2 patients illustrate how developing a movement diagnosis and identifying the contributing factors based on a systematic examination can be used in individuals with TAPR.

Context: A normal breathing pattern while performing the abdominal-hollowing (AH) maneuver or spinal-stabilization exercise is essential for the success of rehabilitation programs and exercises. In previous studies, subjects were given standardized instructions to control the influence of respiration during the AH maneuver. However, the effect of breathing pattern on abdominal-muscle thickness during the AH maneuver has not been investigated. Objective: To compare abdominal-muscle thickness in subjects performing the AH maneuver under normal and abnormal breathing-pattern conditions and to investigate the effect of breathing pattern on the preferential contraction ratio (PCR) of the transverse abdominis. Design: Comparative, repeated-measures experimental study. Setting: University research laboratory. Participants: 16 healthy subjects (8 male, 8 female) from a university population. Measurement: A real-time ultrasound scanner was used to measure abdominal-muscle thickness during normal and abnormal breathing patterns. A paired t test was used to assess the effect of breathing pattern on abdominal-muscle thickness and PCR. Results: Muscle thickness in the transverse abdominis and internal oblique muscles was significantly greater under the normal breathing pattern than under the abnormal pattern (P < .05). The PCR of the transverse abdominis was significantly higher under the normal breathing pattern compared with the abnormal pattern (P < .05). Conclusion: The results indicate that a normal breathing pattern is essential for performance of an effective AH maneuver. Thus, clinicians should ensure that patients adopt a normal breathing pattern before performing the AH maneuver and monitor transverse abdominis activation during the maneuver.

Context: Coactivation of abdominal and pelvic-floor muscles (PFM) is an issue considered by researchers recently. Electromyography (EMG) studies have shown that the abdominal-muscle activity is a normal response to PFM activity, and increase in EMG activity of the PFM concomitant with abdominal-muscle contraction was also reported. Objective: The purpose of this study was to compare the changes in EMG activity of the deep abdominal muscles during abdominal-muscle contraction (abdominal hollowing and bracing) with and without concomitant PFM contraction in healthy and low-back-pain (LBP) subjects. Design: A 2 × 2 repeated-measures design. Setting: Laboratory. Participants: 30 subjects (15 with LBP, 15 without LBP). Main outcome measures: Peak rectified EMG of abdominal muscles. Results: No difference in EMG of abdominal muscles with and without concomitant PFM contraction in abdominal hollowing (P = .84) and abdominal bracing (P = .53). No difference in EMG signal of abdominal muscles with and without PFM contraction between LBP and healthy subjects in both abdominal hollowing (P = .88) and abdominal bracing (P = .98) maneuvers. Conclusion: Adding PFM contraction had no significant effect on abdominal-muscle contraction in subjects with and without LBP.

Individuals with low back pain (LBP) are thought to benefit from interventions that improve motor control of the lumbopelvic region. It is unknown if therapeutic exercise can acutely facilitate activation of lateral abdominal musculature. To investigate the ability of 2 types of bridging-exercise progressions to facilitate lateral abdominal muscles during an abdominal drawing-in maneuver (ADIM) in individuals with LBP. Randomized control trial. University research laboratory. 51 adults (mean ± SD age 23.1 ± 6.0 y, height 173.6 ± 10.5 cm, mass 74.7 ± 14.5 kg, and 64.7% female) with LBP. All participants met 3 of 4 criteria for stabilization-classification LBP or at least 6 best-fit criteria for stabilization classification. Participants were randomly assigned to either traditional-bridge progression or suspension-exercise-bridge progression, each with 4 levels of progressive difficulty. They performed 5 repetitions at each level and were progressed based on specific criteria. Muscle thickness of the external oblique (EO), internal oblique (IO), and transversus abdominis (TrA) was measured during an ADIM using ultrasound imaging preintervention and postintervention. A contraction ratio (contracted thickness:resting thickness) of the EO, IO, and TrA was used to quantify changes in muscle thickness. There was not a significant increase in EO (F1,47 = 0.44, P = .51) or IO (F1,47 = .30, P = .59) contraction ratios after the exercise progression. There was a significant (F1,47 = 4.05, P = .05) group-by-time interaction wherein the traditional-bridge progression (pre = 1.55 ± 0.22; post = 1.65 ± 0.21) resulted in greater (P = .03) TrA contraction ratio after exercise than the suspension-exercise-bridge progression (pre = 1.61 ± 0.31; post = 1.58 ± 0.28). A single exercise progression did not acutely improve muscle thickness of the EO and IO. The magnitude of change in TrA muscle thickness after the traditional-bridging progression was less than the minimal detectable change, thus not clinically significant.

Context: As high school female athletes demonstrate a rate of noncontact anterior cruciate ligament (ACL) injury 3-6 times higher than their male counterparts, research suggests that sagittal-plane hip strength plays a role in factors associated with ACL injuries. Objective: To determine if gender or age affect hip-abductor strength in a functional standing position in young female and male athletes. Design: Prospective cohort design. Setting: Biomechanical laboratory. Participants: Over a 3-y time period, 852 isokinetic hip-abduction evaluations were conducted on 351 (272 female, 79 male) adolescent soccer and basketball players. Intervention: Before testing, athletes were secured in a standing position, facing the dynamometer head, with a strap secured from the uninvolved side and extending around the waist just above the iliac crest. The dynamometer head was positioned in line with the body in the coronal plane by aligning the axis of rotation of the dynamometer with the center of hip rotation. Subjects performed 5 maximum-effort repetitions at a speed of 120°/s. The peak torque was recorded and normalized to body mass. All test trials were conducted by a single tester to limit potential interrater test error. Main outcome measure: Standing isokinetic hip-abduction torque. Results: Hip-abduction torque increased in both males and females with age (P < .001) on both the dominant and nondominant sides. A significant interaction of gender and age was observed (P < .001), which indicated that males experienced greater increases in peak torque relative to body weight than did females as they matured. Conclusions: Males exhibit a significant increase in normative hip-abduction strength, while females do not. Future study may determine if the absence of similar increased relative hip-abduction strength in adolescent females, as they age, may be related to their increased risk of ACL injury compared with males.

Context: Gluteus medius (Gmed) weakness is associated with some lower-extremity injuries. People with Gmed weakness might compensate by activating the tensor fasciae latae (TFL). Different hip rotations in the transverse plane may affect Gmed and TFL muscle activity during isometric side-lying hip abduction (SHA). Objectives: To compare Gmed and TFL muscle activity and the Gmed:TFL muscle-activity ratio during SHA exercise with 3 different hip rotations. Design: The effects of different hip rotations on Gmed, TFL, and the Gmed:TFL muscle-activity ratio during isometric SHA were analyzed with 1-way, repeated-measures analysis of variance. Setting: University research laboratory. Participants: 20 healthy university students were recruited in this study. Interventions: Participants performed isometric SHA: frontal SHA with neutral hip (frontal SHAN), frontal SHA with hip medial rotation (frontal SHA-MR), and frontal SHA with hip lateral rotation (frontal SHA-LR). Main outcome measures: Surface electromyography measured the activity of the Gmed and the TFL. A 1-way repeated-measures analysis of variance assessed the statistical significance of Gmed and TFL muscle activity. When there was a significant difference, a Bonferroni adjustment was performed. Results: Frontal SHA-MR showed significantly greater Gmed muscle activation than frontal SHA-N (P = .000) or frontal SHA-LR (P = .015). Frontal SHA-LR showed significantly greater TFL muscle activation than frontal SHA-N (P = .002). Frontal SHA-MR also resulted in a significantly greater Gmed:TFL muscle-activity ratio than frontal SHA-N (P = .004) or frontal SHA-LR (P = .000), and frontal SHA-N was significantly greater than frontal SHA-LR (P = .000). Conclusions: Frontal SHA-MR results in greater Gmed muscle activation and a higher Gmed:TFL muscle ratio.

Individuals with a history of low back pain (LBP) may present with decreased hip abduction strength and increased trunk or gluteus maximus (GMax) fatigability. However, the effect of hip abduction exercise on hip muscle function has not been previously reported. To compare hip abduction torque and muscle activation of the hip, thigh and trunk between individuals with and without a history of LBP during repeated bouts of side-lying hip abduction exercise. Repeated Measures. Clinical Laboratory. 12 individuals with a history of LBP and 12 controls. Repeated thirty seconds hip abduction contractions. Hip abduction torque, normalized root-mean-squared (RMS) muscle activation, percent RMS muscle activation, and forward general linear regression. Hip abduction torque reduced in all participants as a result of exercise (1.57±0.36 Nm/kg, 1.12±0.36 Nm/kg, p<.001), but there were no group differences (F=0.129, p=.723) or group by time interactions (F=1.098, p=.358). All participants had increased GMax activation during the first bout of exercise (0.96±1.00, 1.18±1.03, p=.038). Individuals with a history of LBP had significantly greater GMax activation at multiple points during repeated exercise (p<.05), and a significantly lower percent of muscle activation for the GMax (p=.050) at the start of the third bout of exercise and biceps femoris (p=.039) at the end of exercise. The gluteal muscles best predicted hip abduction torque in controls, while no consistent muscles were identified for individuals with a history of LBP. Hip abduction torque decreased in all individuals following hip abduction exercise, although individuals with a history of LBP had increased GMax activation during exercise. Gluteal muscle activity explained hip abduction torque in healthy individuals, but not in those with a history of LBP. Alterations in hip muscle function may exist in individuals with a history of LBP.

Standing and sidelying external rotation exercises produce high activation of the deltoid and infraspinatus. Slight shoulder abduction during these exercises may decrease deltoid activity and increase infraspinatus activity. To determine if the addition of a towel under the arm during standing and sidelying external rotation affects infraspinatus, middle and posterior deltoid, and pectoralis major activation characteristics, compared to the no towel condition. Controlled laboratory study. 20 male volunteers (age: 26 ± 3 yrs; height: 1.80 ± 0.07 m; mass: 77 ± 10 kg) who were right-hand dominant and had bilaterally healthy shoulders with no current cervical pathology, and no skin infection or shoulder lesion. External rotation exercises without a towel roll (0° shoulder abduction) and with a towel roll (30° shoulder abduction) were performed in a standing and sidelying position. Maximal voluntary isometric contraction for the infraspinatus, middle and posterior deltoid, and pectoralis major and external rotation in standing and sidelying with and without a towel roll were performed. Normalized average and peak surface EMG amplitude was compared between the towel conditions during standing and sidelying external rotation. Both infraspinatus and pectoralis major activity had no significant differences between the towel conditions in standing and sidelying (P > 0.05). In standing and sidelying, posterior deltoid activity was significantly greater with a towel roll (P < 0.05). Middle deltoid activity had no significant differences between the towel conditions in standing (P > 0.05). However, in sidelying, middle deltoid activity was significantly lower with a towel roll (P < 0.05). Middle deltoid activity decreased with a towel roll during sidelying exercises. More data are needed to determine if a towel roll could be used to potentially reduce superior glide during external rotation exercises.

The Bodyblade Pro is used for shoulder rehabilitation after injury. Resistance is provided by blade Oscillations-faster oscillations or higher speeds correspond to greater resistance. However, research supporting the Bodyblade Pro's use is scarce, particularly in comparison with dumbbell training. To compare muscle activity, using electromyography (EMG), in the back and shoulder regions during shoulder exercises with the Bodyblade Pro vs dumbbells. Randomized crossover study. San Diego State University biomechanics laboratory. 11 healthy male subjects age 19-32 y. Subjects performed shoulder-flexion and -abduction exercises using a Bodyblade Pro and dumbbells (5, 8, and 10 lb) while EMG recorded activity of the deltoid, pectoralis major, infraspinatus, serratus anterior, and erector spinae. Average peak muscle activity (% maximum voluntary isometric contraction) was separately measured for shoulder abduction and flexion in the range of 85° to 95°. Differences among exercise devices were separately analyzed for the flexed and abducted positions using 1-way repeated-measures ANOVA. The Bodyblade Pro produced greater muscle activity than all the dumbbell trials. Differences were significant for all muscles measured (all P < .01) except for the erector spinae during shoulder flexion with a 10-lb dumbbell. EMG activity for the Bodyblade Pro exceeded 50% of the MVIC during both shoulder flexion and abduction. For the dumbbell conditions, only the 10-lb trials approached this effect. Using a Bodyblade during shoulder exercises results in greater shoulder- and back-muscle recruitment than dumbbells. The Bodyblade Pro can activate multiple muscles in a single exercise and thereby minimize the need for multiple dumbbell exercises. The Bodyblade Pro is an effective device for shoulder- and back-muscle activation that warrants further use by clinicians interested in its use for rehabilitation.

To determine if females with hip abductor weakness are more likely to demonstrate greater knee abduction during the stance phase of running than a strong hip abductor group. Observational prospective study design. University biomechanics laboratory. 15 females with weak hip abductors and 15 females with strong hip abductors. Group differences in lower extremity kinematics were analyzed using repeated measures ANOVA with one between factor of group and one within factor of position with a significance value of P < .05. The subjects with weak hip abductors demonstrated greater knee abduction during the stance phase of treadmill running than the strong group (P < .05). No other significant differences were found in the sagittal or frontal plane measurements of the hip, knee, or pelvis. Hip abductor weakness may influence knee abduction during the stance phase of running.

It has been theorized that a positive Trendelenburg test (TT) indicates weakness of the stance hip-abductor (HABD) musculature, results in contralateral pelvic drop, and represents impaired load transfer, which may contribute to low back pain. Few studies have tested whether weakness of the HABDs is directly related to the magnitude of pelvic drop (MPD). To examine the relationship between HABD strength and MPD during the static TT and during walking for patients with nonspecific low back pain (NSLBP) and healthy controls (CON). A secondary purpose was to examine this relationship in NSLBP after a 3-wk HABD-strengthening program. Quasi-experimental. Clinical research laboratory. 20 (10 NSLBP and 10 CON). HABD strengthening. Normalized HABD strength, MPD during TT, and maximal pelvic frontal-plane excursion during walking. At baseline, the NSLBP subjects were significantly weaker (31%; P = .03) than CON. No differences in maximal pelvic frontal-plane excursion (P = .72), right MPD (P = 1.00), or left MPD (P = .40) were measured between groups. During the static TT, nonsignificant correlations were found between left HABD strength and right MPD for NSLBP (r = -.32, P = .36) and CON (r = -.24, P = .48) and between right HABD strength and left MPD for NSLBP (r = -.24, P = .50) and CON (r = -.41, P = .22). Nonsignificant correlations were found between HABD strength and maximal pelvic frontal-plane excursion for NSLBP (r = -.04, P = .90) and CON (r = -.14, P = .68). After strengthening, NSLBP demonstrated significant increases in HABD strength (12%; P = .02), 48% reduction in pain, and no differences in MPD during static TT and maximal pelvic frontal-plane excursion compared with baseline. HABD strength was poorly correlated to MPD during the static TT and during walking in CON and NSLBP. The results suggest that HABD strength may not be the only contributing factor in controlling pelvic stability, and the static TT has limited use as a measure of HABD function.

It has been postulated that subjects with weak hip abductors and external rotators may demonstrate increased knee valgus, which may in turn raise risk of injury to the lower extremity. Recent studies have explored the potential link between hip strength and knee kinematics, but there has not yet been a review of this literature. To conduct a systematic review assessing the potential link between hip-abductor or external-rotator strength and knee-valgus kinematics during dynamic activities in asymptomatic subjects. An online computer search was conducted in early February 2011. Databases included Medline, EMBASE, CINAHL, SPORTDiscus, and Google Scholar. Inclusion criteria were English language, asymptomatic subjects, dynamometric hip-strength assessment, single or multicamera kinematic analysis, and statistical analysis of the link between hip strength and knee valgus via correlations or tests of differences. Data were extracted concerning subject characteristics, study design, strength measures, kinematic measures, subject tasks, and findings with regard to correlations or group differences. Eleven studies were selected for review, 4 of which found evidence that subjects with weak hip abductors or external rotators demonstrated increased knee valgus, and 1 study found a correlation to the contrary. There is a small amount of evidence that healthy subjects with weak hip abductors and perhaps weak external rotators demonstrate increased knee valgus. However, due to the variation in methodology and lack of agreement between studies, it is not possible to make any definitive conclusions or clinical recommendations based on the results of this review. Further research is needed.

The overarching goal of this study was to examine the use of tri-axial accelerometers in measuring upper extremity motions to monitor upper extremity exercise compliance. There were multiple questions investigated but the primary objective was to investigate the correlation between visually observed arm motions and tri-axial accelerometer activity counts in order to establish fundamental activity counts for the upper extremity. Cross-sectional, Basic Research. Clinical Laboratory. Thirty healthy individuals age = 26 ± 6 years, body mass = 24 ± 3 kg, and height = 1.68 ± 0.09 m volunteered. Participants performed three series of tasks: 1) activities of daily living, 2) rehabilitation exercises 3) passive shoulder range of motion at 5 specific velocities on an isokinetic dynamometer while wearing an accelerometer on each wrist. Participants performed exercises with dominant arm to examine differences between sides. A researcher visually counted all arm motions in order to correlate counts with physical activity counts provided by the accelerometer. Physical activity counts derived from the accelerometer and visual observed activity counts recorded from a single investigator. There was a strong positive correlation (r=.93, p<0.01) between accelerometer physical activity counts and visual activity counts for all ADL's. Accelerometers activity counts demonstrated side to side difference for all ADL's (p<0.001) and 5 of the 7 rehabilitation activities (p<0.003). All velocities tested on the isokinetic dynamometer were shown to be significantly different from each other (p <0.001). There is a linear relationship between arm motions counted visually and the physical activity counts generated by an accelerometer indicating that arm motions could be potentially accounted for if monitoring arm usage. The accelerometers can detect differences in relatively slow arm movement velocities which is critical if attempting to evaluate exercise compliance during early phase of shoulder rehabilitation. These results provide fundamental information that indicates that tri-axial accelerometers have the potential to objectively monitor and measure arm activities during rehabilitation and activity of daily living.

This study sought to determine the effects of trunk-muscle fatigue and blood lactic acid elevation on static and dynamic balance. Fatigue was induced by an isokinetic protocol, and static and dynamic balance were assessed during bilateral stance using a Kinesthetic Ability Trainer. Subjects participated in a fatigue protocol in which continuous concentric movements at 60 degrees/s were performed until the torque output for both trunk flexion and extension dropped below 25% of the calculated peak torque for 3 consecutive movements. Before and immediately after the fatigue protocol, blood lactic acid measurements and static- and dynamic-balance measurements were recorded. An increase in lactic acid levels was detected in all subjects. According to a dependent-samples t test, significant differences in balance and lactic acid values were found after the fatigue protocol. There was no correlation between lactic acid accumulation (change between prefatigue and postfatigue levels) and balance-score differences. Trunk-muscle fatigue has an adverse effect on static and dynamic balance.

Clinical scenario: Injuries are somewhat commonplace in highly active populations. One strategy for reducing injuries is to identify individuals with an elevated injury risk before participation so that remediative interventions can be provided. Preparticipation screenings have traditionally entailed strength and flexibility measures thought to be indicative of inflated injury risk. Some researchers, however, have suggested that functional movements/tasks should be assessed to help identify individuals with a high risk of future injury. One assessment tool used for this purpose is the Functional Movement Screen (FMS). The FMS generates a numeric score based on performance attributes during 7 dynamic tasks; this score is purported to reflect future injury risk. Expanding interest in the FMS has led researchers to investigate how accurately it can identify individuals with an increased risk of injury. Focused clinical question: Can the Functional Movement Screen accurately identify highly active individuals with an elevated risk of injury?

The cervical spine can be divided into upper and lower units, and each unit makes a different contribution to the magnitude of rotation and proprioception. However, few studies have examined the effect of the cervical rotation positions on proprioception. To compare cervical spine rotation active joint position sense (AJPS) near mid-range-of-motion (ROM) (30°) and near end-ROM (60°). Cross-sectional study. Human Performance Research Laboratory. Fifty-three military helicopter pilots (age = 28.4 ± 6.2 years, height = 175.3 ± 9.3 cm, weight = 80.1 ± 11.8 kg) consented and participated. A motion analysis system was used to record cervical rotation kinematics. Subjects sat in a chair wearing a headband and blind-fold. First, subjects actively rotated the head right or left to a target position (30°/60°) with real-time verbal cues provided by the tester. Subjects held the target position for five seconds and then returned to the start position. Following this, subjects replicated the target position as closely as possible. Five trials were performed in both directions to both target positions (R30/R60/L30/L60). Order of direction/position was randomized. The difference between target and replicated position was calculated and defined as absolute error (AE), the mean of five trials used for analyses. Wilcoxon Signed Ranks tests were used to compare AJPS at the different target positions (p<0.0125 with Bonferroni adjustments). End-ROM AE were significantly more accurate than mid-ROM AE (p = 0.001). Cervical spine rotation AJPS is more accurate near end-ROM versus mid-ROM. Both target positions should be used to examine cervical spine rotation AJPS of both the upper and lower units.

With a limited number of outcomes-based studies, only recommendations for strength-training and rehabilitation programs can be made. To determine the extent to which throwing accuracy, core stability, and proprioception improved after completion of a 6-week training program that included open kinetic chain (OKC), closed kinetic chain (CKC), and/or core-stability exercises. A 2 x 3 factorial design. Division III college. 19 healthy baseball athletes with a control group of 15. Two 6-week programs including OKC, CKC, and core-stabilization exercises that were progressed each week. Functional throwing-performance index, closed kinetic chain upper extremity stability test, back-extensor test, 45 degrees abdominal-fatigue test, and right- and left-side bridging test. There was no significant difference between groups. An increase was evident in all pretest-to-posttest results, with improvement ranging from 1.36% to 140%. Both of the 6-week training programs could be used to increase throwing accuracy, core stability, and proprioception in baseball.