Self-Myofascial Release of the Superficial Back Line Improves Sit-and-Reach Distance.

CONTEXT: Decreased hamstring flexibility can lead to a plethora of musculoskeletal injuries, including low back pain, hamstring strains, and patellofemoral pain. Lack of flexibility may be the result of myofascial adhesions. The fascia connected to the hamstrings is part of the superficial back line that runs from the cranium to the plantar aspect of the foot. Any disruption along this chain may limit the flexibility of the hamstring. OBJECTIVE: To investigate if self-myofascial release (SMR) of the plantar surface of the foot in addition to the hamstring group was more effective at improving the flexibility of the hamstrings when compared with either intervention alone. DESIGN: Cross-over study. SETTING: Athletic training facility. PARTICIPANTS: Fifteen college students (5 males and 10 females; age: 20.9 [1.4] y, height: 173.1 [10.3] cm, mass: 80.0 [24.9] kg) who were not older than 30, with no history of low back pain or injury within the past 6 months, no history of leg pain or injury within the past 6 months, no current signs or symptoms of cervical or lumbar radicular pain, no current complaint of numbness or tingling in the lower-extremity, and no history of surgery in the lower-extremity or legs. INTERVENTIONS: Each participant received each intervention separated by at least 96 hours in a randomized order: hamstring foam rolling, lacrosse ball on the plantar surface of the foot, and a combination of both. MAIN OUTCOME MEASURES: The sit-and-reach test evaluated hamstring flexibility of each participant before and immediately after each intervention. RESULTS: There were no significant differences found among the SMR techniques on sit-and-reach distance (F2,41 = 2.7, P = .08, ηp2=.12). However, at least 20% of participants in each intervention improved sit-and-reach distance by 2.5 cm. CONCLUSIONS: SMR may improve sit-and-reach distance, but one technique of SMR does not seem to be superior to another.

Effect of Ankle Positioning During Hamstring Stretches for Improving Straight Leg Hip Flexion Motion.

OBJECTIVE: To compare the effects of stretching the hamstrings with the ankle in either a plantar-flexed (PF) or dorsiflexed (DF) position for improving straight leg hip flexion range of motion (ROM) over a 4-week period. DESIGN: Randomized, single-blinded, pretest, posttest design. SETTING: Athletic training facility. PARTICIPANTS: Each limb of 34 asymptomatic individuals (15 males, 19 females) was randomly assigned to one of the 3 groups. Twenty-four limbs received hamstring stretches with the ankle in DF, 24 limbs received hamstring stretches with the ankle in PF, and 20 limbs received no stretch (control). INDEPENDENT VARIABLES: Ankle position (PF, DF) during hamstring stretching. MAIN OUTCOME MEASURES: We measured pretest and posttest passive straight leg hip flexion ROM with the test ankle in a neutral position. For the intervention groups, the test limb was passively stretched with the ankle held in end range DF or PF for their respective group. Each stretch was held for 30 seconds for a total of 3 applications. Two treatment sessions were completed per week for a total of 4 weeks. The control limbs received no stretching during the 4-week period. We conducted 1-way analyses of covariance to determine significant changes in ROM between groups (P < 0.05). RESULTS: There was no significant difference between treatment groups (P = 0.90), but a significant difference was found for both the PF (P = 0.04) and DF (P = 0.01) groups when compared with the control group. CONCLUSIONS: Our findings indicate that both stretching the hamstrings in either PF or DF improve straight leg hip ROM compared with a control group. CLINICAL RELEVANCE: The results of this study should be considered by clinicians when determining the optimal stretching techniques aimed at increasing hamstring length.

Decreased blood flow in the throwing arm of professional baseball pitchers.

BACKGROUND: As a consequence of the repetitive forces placed on the throwing arm of a baseball player, various bony, capsuloligamentous, and muscular adaptations occur and have been identified. However, no research has identified whether adaptations also exist in the vasculature of the upper extremity in the competitive baseball player. METHODS: Fifty-one professional baseball pitchers and 34 position players participated. Diagnostic ultrasound was used to measure bilateral blood flow of the brachial artery. These measurements were taken with the participant standing with the test arm resting at the participant's side and again with the test arm in a provocative shoulder position. RESULTS: The throwing arm of the pitchers had significantly less blood flow volume when in the provocative shoulder position compared with their nonthrowing arm (P = .01). Pitchers did not have any bilateral difference while in the resting position (P = .19). There were no bilateral differences among the position players while in the resting (P = .64) or provocative positions (P = .63). Pitchers had significantly less blood flow of the throwing shoulder while in the provocative position compared with position players (P = .02). There were no other between-group differences. CONCLUSIONS: While in a provocative shoulder position, pitchers have significantly less blood flow in their throwing arm compared with their nonthrowing arm and with the throwing arm of position players. These results provide a descriptive profile of blood flow volume among baseball players, which may be used in the evaluation and treatment of such athletes with vascular disorders.

Microvascular perfusion increases after eccentric exercise of the gastrocnemius.

OBJECTIVES: The purpose of this study was to assess microvascular perfusion immediately after eccentric exercise using contrast-enhanced sonography. METHODS: An intravenous catheter was placed in the antecubital vein of the arm contralateral to the leg being tested for the delivery of microbubbles to 18 healthy volunteers (mean age ± SD, 22.2 ± 2.2 years; height, 166.0 ± 11.9 cm; weight, 69.4 ± 25.0 kg). Eccentric exercises were performed unilaterally in a randomized leg. Calf-lowering repetitions off a raised step were performed to the beat of a metronome over 3 seconds in the sequence of 50 repetitions, 5 minutes of rest, and 50 repetitions. Microvascular perfusion (blood volume, blood flow, and blood flow velocity) was measured before and immediately after exercise using replenishment kinetics. RESULTS: Blood volume and flow both significantly increased after exercise (P < .001). Baseline measurements were 5.88 ± 1.33 dB and 2.34 ± 0.41 dB/s and increased to 12.20 ± 3.31 dB and 4.52 ± 1.05 dB/s, respectively. There was a significant decrease in blood flow velocity (P = .035) after exercise (0.38 ± 0.03 s(-1)) from baseline (0.41 ± 0.06 s(-1)). CONCLUSIONS: Circulatory responses were altered after eccentric exercise, which may be due to the metabolic demand placed on the body. On the basis of this finding, eccentric exercise may be used as a model to assess the effect modalities have on the circulatory system after an elevated state of microvascular perfusion is reached.

Transversus abdominis activation during a side-bridge exercise progression is similar in people with recurrent low back pain and healthy controls.

Low back pain (LBP) affects 70-80% of the population. The transversus abdominis (TrA) has been implicated as part of the cause of LBP. Prevention and rehabilitation of LBP often target the TrA using exercises such as the side bridge accompanied with the abdominal drawing-in maneuver (ADIM). However, it is unknown whether individuals with recurrent LBP, when they are in a period of no pain, are able to activate the TrA and healthy individuals during this exercise. The purpose of our study was to compare the activation ratio of the TrA during a 5-level side-bridge exercise progression. Twenty-three subjects with a history of recurrent, nonspecific LBP, but not experiencing an exacerbation of symptoms and 24 healthy controls volunteered. All the subjects performed the ADIM and side-bridge exercises with clinician feedback (verbal cueing). Each participant performed the side-bridge exercise progression while ultrasound images were taken. The subjects were only progressed if they successfully completed the previous level. The thickness of the TrA was measured in rested and contracted states at each exercise level to find the activation ratio (TrA contracted/TrA rest). Separate analyses of covariance did not reveal a difference in activation ratios between groups (p > 0.40) when the ratio at the lowest level was used as the covariate. The results from this study indicate that both groups were able to contract the TrA with verbal cueing during a side-bridge exercise progression. Because the TrA contracted similarly during exercise in both groups, the association of LBP with the TrA may be because of another mechanism, such as delayed activation in the feed-forward mechanism during activity or a lack of endurance of the TrA.

The effect of cold water immersion on 48-hour performance testing in collegiate soccer players.

This randomized, controlled, laboratory study was designed to examine the effect of cold water immersion (CWI) as a recovery modality on repeat performance on the yo-yo intermittent recovery test (YIRT), a widely accepted tool for the evaluation of physical performance in soccer, separated by 48 hours. Twenty-two healthy Division I collegiate soccer players (13 men and 9 women; age, 19.8 ± 1.1 years; height, 174.0 ± 9.0 cm; mass, 72.1 ± 9.1 kg) volunteered as participants during the noncompetitive season. The YIRT was used to induce volitional fatigue and was administered at baseline and again 48 hours later. Athletes progressively increased sprint speed between markers set 20 m apart until pace was failed. Countermovement vertical jump (CMVJ) was used to assess anaerobic power and was measured before YIRT, immediately post-YIRT, and 24 and 48 hours post-YIRT. A 10-cm horizontal visual analog scale was administered immediately, 24 hours and 48 hours post-YIRT to assess perceived fatigue (PF) in the legs. Participants were randomly placed into the CWI or control group. The CWI condition consisted of immersion to the umbilicus in a 12°C pool for 15 minutes, whereas the control group sat quietly for 15 minutes. There were no significant differences between intervention conditions on YIRT performance (control, 4,900 ± 884 m; CWI, 5,288 ± 1,000 m; p = 0.35) or PF (control, 9.4 ± 0.5 cm; CWI, 9.3 ± 0.6 cm; p = 0.65) at 48 hours post-YIRT. There was a main time effect for CMVJ over 48 hours, but no group differences (pre-YIRT, 64.6 ± 11.0 cm; post-YIRT, 66.4 ± 10.9 cm; 24 hours post-YIRT, 63.4 ± 9.9 cm; 48 hours post-YIRT, 63.1 ± 9.4 cm; p = 0.02). This study demonstrated that in collegiate soccer players, CWI performed immediately and 24 hours after induced volitional fatigue did not affect subsequent physical performance estimates.

Effect of Strength Training on Jump-Landing Biomechanics in Adolescent Females.

BACKGROUND: Sex-based differences in neuromuscular characteristics relevant to anterior cruciate ligament (ACL) injury risk may arise as compensation for divergent strength development during puberty. Strength training during this period may prevent the development of these undesirable neuromuscular characteristics. HYPOTHESIS: Strength-trained middle school girls will have improved jump-landing biomechanics compared with control participants. STUDY DESIGN: Cohort study. LEVEL OF EVIDENCE: Level 3. METHODS: Maximum voluntary isometric contraction in hip extension and abduction and knee extension and flexion as well as Landing Error Scoring System (LESS) scores were collected for healthy female middle school students of grades 6 to 8. Strength-training participants (STR: N = 30; height, 1.63 ± 0.07 m; mass, 48.1 ± 7.6 kg; age, 12.5 ± 1.0 y) were matched with control participants (CON: N = 30; height, 1.60 ± 0.09 m; mass, 47.2 ± 8.9 kg; age, 12.6 ± 0.9 y). The training consisted of a 6-month strength-training program administered through a gym class curriculum that targeted the lower extremity. A repeated-measures mixed-model analysis of variance was used for comparisons between groups and across time (α = 0.05). Stepwise linear regression was used to examine the relationship between strength change and LESS score change. RESULTS: Strength values (N·m/kg) increased across time and to a greater degree in STR for hip extension (baseline 3.98 ± 1.15 vs follow-up 4.77 ± 1.80), hip abduction (4.22 ± 1.09 vs 5.13 ± 2.55), and knee flexion (3.27 ± 0.62 vs 3.64 ± 1.40) compared with CON. LESS grades significantly decreased across time in STR (5.58 ± 1.21 vs 4.86 ± 1.44) and were significantly lower than CON (5.98 ± 1.42) at follow-up (P < 0.001). The change in hip extension and knee extension strength explained 67% of the variance (P < 0.001) in the LESS change score in the STR group. CONCLUSION: A school-based strength-training program that focused on hip and knee musculature significantly improved jump-landing biomechanics (as determined by LESS) relevant to ACL injury risk. Further investigation using different strength-training approaches in this age group is warranted. CLINICAL RELEVANCE: Strength training during adolescence holds promise as an injury prevention program. The use of a school-based approach is novel and may represent a robust opportunity for injury prevention programs, as physical education class is often mandatory in this age group.

US Army Reserve Officers' Training Corps Cadets' Knowledge of Exercise-related Musculoskeletal Injuries.

Musculoskeletal injuries, especially resulting from physical training, are a significant threat to military readiness. Due to costs related to treating injuries and the high probability of chronic, recurrent injuries, prevention should be a primary focus to maximize human performance and military success. However, in the US Army, many personnel are uninformed on injury prevention topics, and no research has identified injury prevention knowledge gaps in military leaders. This study examined the current knowledge of US Army ROTC cadets on injury prevention topics. This cross-sectional study was conducted at two university ROTC programs in the US. Cadets completed a questionnaire to identify participants' knowledge of injury risk factors and effective prevention strategies. Participants' perceptions of their leadership and their desires for future injury prevention education were also assessed. The survey was completed by 114 cadets. Except for dehydration and prior injury, participants had a greater than 10% incorrect response rate for questions regarding the impact of various factors on injury risk. Overall, participants displayed a positive view of their leadership's interest in injury prevention. The majority (74%) of participants reported a preference to receive injury prevention educational materials via electronic delivery. To develop implementation strategies and educational materials for injury prevention, identifying current injury prevention knowledge of military personnel should be a priority for researchers and military leaders. The initial military training of future officers is a critical time for further research and education efforts to improve the effectiveness and adoption of injury prevention strategies.

Dry Cupping Therapy for Improving Nonspecific Neck Pain and Subcutaneous Hemodynamics.

CONTEXT: Dry cupping therapy is a noninvasive treatment commonly used to reduce pain and promote the healing process in various populations, including those with nonspecific neck pain; however, no data are available to support most of this method's true physiological benefits. OBJECTIVE: To determine if dry cupping therapy decreased pain and increased subcutaneous blood flow compared with sham cupping and control conditions. DESIGN: Controlled laboratory study. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: A total of 32 participants (age = 22.5 ± 2.8 years, height = 173.3 ± 10.1 cm, mass = 76.6 ± 18.7 kg) with self-reported nonspecific neck pain. INTERVENTION(S): We used dry cupping and sham cupping interventions and a control condition. For the dry cupping intervention, 1 stationary cup was placed directly over the most painful area for 8 minutes. The sham cupping intervention followed the same procedures as the dry cupping intervention except a sham cup was applied. For the control condition, participants received no treatment. MAIN OUTCOME MEASURE(S): Subjective pain intensity (visual analog scale); pain-pressure threshold; subcutaneous hemodynamics, including superficial and deep oxygenated, deoxygenated, and total hemoglobin levels; and tissue saturation index. RESULTS: We observed differences in the visual analog scale score and the superficial and deep oxygenated and total hemoglobin levels (P values ≤ .002) immediately postintervention compared with baseline. Post hoc tests revealed that the dry cupping group had less pain than the sham cupping and control groups and higher superficial and deep oxygenated and total hemoglobin levels (P values ≤ .008). No differences were found between baseline and 24 hours postintervention. CONCLUSIONS: A single session of dry cupping therapy may be an effective short-term treatment method for immediately reducing pain and increasing oxygenated and total hemoglobin levels in patients with nonspecific neck pain.

Cooling of Lower Extremity Muscles According to Subcutaneous Tissue Thickness.

CONTEXT: When using an ice bag, previous researchers recommended cooling times based on the amount of subcutaneous tissue. Unfortunately, many clinicians are unaware of these recommendations or whether they can be applied to other muscles. OBJECTIVE: To examine if muscles of the lower extremity cool similarly based on recommended cooling times. DESIGN: Crossover study. SETTING: Athletic training laboratory. PATIENTS OR OTHER PARTICIPANTS: Fourteen healthy participants volunteered (8 men, 6 women; age = 21.1 ± 2.2 years, height = 174.2 ± 4.5 cm, weight = 74.0 ± 7.5 kg). INTERVENTION(S): Subcutaneous tissue thickness was measured at the largest girth of the thigh, medial gastrocnemius, and medial hamstring. Participants were randomized to have either the rectus femoris or medial gastrocnemius and medial hamstring tested first. Using sterile techniques, the examiner inserted a thermocouple 1 cm into the muscle after accounting for subcutaneous tissue thickness. After the temperature stabilized, a 750-g ice bag was applied for 10 to 60 minutes to the area(s) for the recommended length of time based on subcutaneous adipose thickness (0 to 5 mm [10 minutes]; 5.5 to 10 mm (25 minutes]; 10.5 to 15 mm [40 minutes]; 15.5 to 20 mm [60 minutes)]. After the ice bag was removed, temperature was monitored for 30 minutes. At least 1 week later, each participant returned to complete testing of the other muscle(s). MAIN OUTCOME MEASURE(S): Intramuscular temperature (°C) at baseline, end of treatment time (0 minutes), and posttreatment recovery (10, 20, and 30 minutes postintervention). RESULTS: At the end of treatment, temperature did not differ by subcutaneous tissue thickness (10 minutes = 29.0°C ± 3.8°C, 25 minutes = 28.7°C ± 3.2°C, 40 minutes = 28.7°C ± 6.0°C, 60 minutes = 30.0°C ± 2.9°C) or muscle (rectus femoris = 30.1°C ± 3.8°C, gastrocnemius = 28.6°C ± 5.4°C, hamstrings = 28.1°C ± 2.5°C). No significant interaction was present for subcutaneous tissue thickness or muscle (P ≥ .126). CONCLUSIONS: Lower extremity muscles seemed to cool similarly based on the recommended cooling times for subcutaneous tissue thickness. Clinicians should move away from standardized treatment times and adjust the amount of cooling time by ice-bag application based on subcutaneous tissue thickness.

TRANSVERSUS ABDOMINIS ACTIVATION AND TIMING IMPROVES FOLLOWING CORE STABILITY TRAINING: A RANDOMIZED TRIAL.

BACKGROUND: Patients with non-specific low back pain (LBP) often present with a decrease in transversus abdominis (TrA) muscle activation and delayed onset of contraction with extremity movements, potentially contributing to recurrent LBP. Core stability is required for extremity movement and if the timing of when the TrA contracts is not corrected patients may continue to experience LBP. HYPOTHESIS/PURPOSE: The purpose of this study was to assess the effects of a four-week core stability rehabilitation program on TrA activation ratio and when the TrA initiates contraction during upper extremity movements in subjects with and without LBP. It was hypothesized that those with LBP would experience greater changes in TrA activation and onset of contraction by the TrA compared to the healthy group. STUDY DESIGN: Randomized Clinical Trial. METHODS: Forty-two participants volunteered (21 healthy and 21 LBP). Ultrasound imaging measured the TrA activation ratio and time of initial contraction of the TrA during upper extremity movement into flexion. Half of the healthy and LBP participants were assigned to the exercise group. Participants reported twice a week to the athletic training facility to complete an exercise progression of three exercises. After four weeks, all participants returned to have TrA activation and timing measured again. RESULTS: Pertaining to demographics, there were no differences between the healthy and LBP participants. There was a group interaction for both TrA activation ratio (p=.049) and onset of initial contraction (p=.008). Those in the exercise group showed an increase in TrA activation ratio (1.85 ± 0.09) compared to the control group (1.79 ± 0.08), as well as an improvement in the onset of contraction (2.07 ± 0.08 seconds) compared to the control group (2.23 ± 0.09 seconds) after the four-week rehabilitation program. Strong effect sizes for TrA activation ratio (0.71 [0.06-1.35]) and initial onset of TrA contraction (-1.88 [-2.63 - -1.11]) were found indicating clinical differences related to the interventions. CONCLUSION: TrA activation and timing were altered following a four-week core stability program in people with and without LBP. Clinicians should consider incorporating these exercises for improving the function of the TrA. LEVEL OF EVIDENCE: Therapy, level 2b.

Forward Shoulder Posture in Collegiate Swimmers: A Comparative Analysis of Muscle-Energy Techniques.

CONTEXT: Empirical data for treating forward shoulder posture supports stretching the anterior shoulder musculature. Although muscle-energy techniques (METs) have been hypothesized to lengthen muscle, no data have described the usefulness of this technique among swimmers. OBJECTIVE: To determine if an MET provides improvements in resting pectoralis minor length (PML), forward scapular position, and scapular upward rotation in female collegiate swimmers. DESIGN: Controlled laboratory study. SETTING: Athletic training room. PATIENTS OR OTHER PARTICIPANTS: Thirty-nine asymptomatic National Collegiate Athletic Association Division I women's swimmers (19 experimental, 20 control). INTERVENTION(S): The experimental group received 2 treatment sessions per week for 6 weeks. The control group received no intervention during this 6-week period. MAIN OUTCOME MEASURE(S): We administered pretest and posttest measurements for PML, forward scapular position, and scapular upward rotation in positions of rest and 60°, 90°, and 120° of humeral elevation. The MET consisted of a 3-second stretch in the direction of the pectoralis minor fibers, followed by a 5-second isometric horizontal adduction contraction at 25% of maximum force. Immediately after this contraction, the entire sequence was repeated with the muscle being stretched to the new endpoint. A total of 4 cycles of MET were continuously applied per treatment session twice per week for 6 weeks. We conducted 1-way analyses of covariance to determine any between-groups postintervention test differences. RESULTS: The MET group had a greater increase in PML postintervention (P = .001, effect size = 1.6) and a greater decrease in forward scapular position postintervention (P = .001, effect size = 1.07) compared with the control group. No differences were found for scapular upward rotation (P > .10). CONCLUSIONS: Our results indicate that 6 weeks of MET treatments applied to the pectoralis minor of asymptomatic female swimmers provided improvements in PML and forward scapular position compared with a control group.

Blood flow after exercise-induced muscle damage.

CONTEXT: The most common modality used to address acute inflammation is cryotherapy. Whereas pain decreases with cryotherapy, evidence that changes occur in perfusion of skeletal muscle is limited. We do not know whether ice attenuates the increases in perfusion associated with acute inflammation. OBJECTIVE: To examine the effects of repeated applications of ice bags on perfusion of the gastrocnemius muscle after an eccentric exercise protocol. DESIGN: Controlled laboratory study. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: Eighteen healthy participants (3 men, 15 women; age = 22.2 ± 2.2 years, height = 166.0 ± 11.9 cm, mass = 69.4 ± 25.0 kg). INTERVENTION(S): To induce eccentric muscle damage, participants performed 100 unilateral heel-lowering exercises off a step to the beat of a metronome. A randomized intervention (cryotherapy, sham, control) was applied to the exercised lower extremity immediately after the protocol and again at 10, 24, and 34 hours after the protocol. MAIN OUTCOME MEASURE(S): Baseline perfusion measurements (blood volume, blood flow, and blood flow velocity) were taken using contrast-enhanced ultrasound of the exercised leg. Perfusion was reassessed after the first intervention and 48 hours after the protocol as percentage change scores. Pain was measured with a visual analog scale at baseline and at 10, 24, 34, and 48 hours after the protocol. Separate repeated-measures analyses of variance were used to assess each dependent variable. RESULTS: We found no interactions among interventions for microvascular perfusion. Blood volume and blood flow, however, increased in all conditions at 48 hours after exercise (P < .001), and blood flow velocity decreased postintervention from baseline (P = .041). We found a time-by-intervention interaction for pain (P = .009). Visual analog scale scores were lower for the cryotherapy group than for the control group at 34 and 48 hours after exercise. CONCLUSIONS: Whereas eccentric muscle damage resulted in increased blood flow, ice did not decrease muscle perfusion 48 hours after exercise. Therefore, ice does not seem to decrease muscle perfusion when blood flow is elevated, as it would be during inflammation.

Microvascular perfusion and intramuscular temperature of the calf during cooling.

PURPOSE: The study's purpose was to examine how the microvascularity of the gastrocnemius changed after a cryotherapy intervention based on subcutaneous tissue thickness. A secondary purpose was to compare intramuscular temperature change to subcutaneous tissue thickness. METHODS: This was a single-blinded crossover study; each subject received both conditions (cryotherapy or sham). Subjects had baseline measurements of blood flow, blood volume, and intramuscular temperature recorded at 1 cm into the muscle belly of the medial gastrocnemius. The randomized condition was applied for 10, 25, 40, or 60 min, depending on subcutaneous tissue thickness. Immediate posttreatment microvascular measures were taken. After a designated rewarming period, again based on subcutaneous tissue thickness, measurements were retaken. At least 48 h separated the two conditions. RESULTS: There were significant condition × time interactions for blood flow (P = 0.01), blood volume (P = 0.022), and intramuscular temperature (P < 0.001). For blood flow and volume, the cryotherapy condition maintained baseline levels, whereas the sham condition increased immediately after treatment and rewarming. For intramuscular temperature, the cryotherapy condition caused a decrease in intramuscular temperature from baseline compared with no change in the sham condition from baseline. Intramuscular temperature change was significantly correlated to subcutaneous tissue thickness (r = 0.49, P = 0.05). CONCLUSIONS: Cryotherapy did not decrease blood flow and blood volume from resting levels, although the intramuscular temperature decreased. An intramuscular change of 7°C-9°C may not be cold enough to cause local vasoconstriction.

Subcutaneous thigh fat assessment: a comparison of skinfold calipers and ultrasound imaging.

CONTEXT: Skinfold calipers (SC) typically are used to determine subcutaneous fat thicknesses. Identifying the exact separation of muscle and fat can complicate measurements. Ultrasound imaging (USI) might provide a better technique for analyzing subcutaneous fat thicknesses. OBJECTIVE: To compare measurements from SC and USI in assessing subcutaneous thigh fat thickness. DESIGN: Descriptive laboratory study. SETTING: Laboratory. PATIENTS AND OTHER PARTICIPANTS: Twenty healthy adults (13 men, 7 women; age  =  26.9 ± 5.4 years, height  =  173.9 ± 7.3 cm, mass  =  77.4 ± 16.1 kg) participated. INTERVENTION(S): Participants were seated in 90° of knee flexion and 85° of trunk extension. A standardized template was used to identify measurement sites over the vastus medialis obliquus (VMO), distal rectus femoris (dRF), proximal rectus femoris (pRF), and vastus lateralis (VL). Three measurements at each of the 4 sites were made in random order and were averaged for each measurement tool by the same investigator. MAIN OUTCOME MEASURE(S): Fat thickness was measured in millimeters with SC and USI. Measurements at each site were compared using Pearson product moment correlations and Bland-Altman plots. RESULTS: Strong correlations between measures were found at the VMO (r  =  .90, P < .001), dRF (r  =  .93, P < .001), pRF (r  =  .93, P < .001), and VL (r  =  .91, P < .001). Mean differences between measures ranged from 1.7 ± 2.4 mm (dRF) to 3.7 ± 2.6 mm (pRF), indicating that the SC resulted in larger thicknesses compared with USI. Limits of agreement, as illustrated by the Bland-Altman plots, were fairly wide at each site: from -3.38 mm to 7.74 mm at the VMO, from -3.04 mm to 6.52 mm at the dRF, from -1.53 mm to 8.87 mm at the pRF, and from -3.73 mm to 8.15 mm at the VL. All plots except for the VL demonstrated increasing overestimation via the SC as fat thicknesses increased. CONCLUSIONS: We found strong correlations between the SC and USI; however, the large limits of agreement and increasing mean differences with larger fat thicknesses were a concern in terms of using this tool. When measuring subcutaneous fat thickness of the thigh, SC tended to overestimate thickness in individuals with higher fat values.

No difference between doses in skin anesthesia after lidocaine delivered via iontophoresis.

CONTEXT: Iontophoresis is a method of administering medications transcutaneously using galvanic current. Dose is the product of current amplitude and treatment duration. It is assumed that higher doses of iontophoresis are more effective in delivering medication, yet research supporting this claim is insufficient. OBJECTIVE: To compare high-dose lidocaine iontophoresis (80 mA-min), standard-dose lidocaine iontophoresis (40 mA-min), and 2 sham treatments indirectly by measuring skin anesthesia. DESIGN: Double-blind crossover study. SETTING: Research laboratory. PARTICIPANTS: 15 healthy volunteers (10 women, 5 men: age 24.06 ± 2 y, height 169.7 ± 8.3 cm, weight 72.5 ± 14.2 kg). INTERVENTION: Four treatments were counterbalanced and applied on the anterior forearm: 2 true interventions (40 and 80 mA-min) and 2 sham interventions separated by at least 24 h. The true-intervention doses were applied at a current of 2 mA with 2.5 ml 2% lidocaine HCL for 20 and 40 min. The sham treatments were 2.5 ml of lidocaine without galvanic current (intensity = 0 mA, 40 min) and 2.5 ml of saline solution (galvanic current of 2 mA for 40 min). MAIN OUTCOME MEASURES: Semmes-Weinstein monofilament scores were taken preintervention and postintervention (at 0, 20, 40, and 60 min) to measure skin anesthesia. RESULTS: A significant interaction between treatment and time (F = 4.137, P < .01) was identified. The 40-mA-min dose produced greater anesthesia than the lidocaine and saline shams at all times. The 80-mA-min dose produced greater anesthesia than saline sham at all times. There was a significant difference noted, with 40 mA-min over 80 mA-min, at the 20-min posttest, but there were no other significant differences between the 40- and 80-mA-min doses at 0, 40, or 60 min posttreatment or between the 2 sham treatments at any time. CONCLUSIONS: The 40-mA-min treatment was just as effective as the 80-mA-min treatment, suggesting that shorter treatments may be more time efficient for clinicians and patients.

The anesthetic effect of lidocaine after varying times of phonophoresis.

OBJECTIVE: This study aimed to determine the anesthetic effect of 1-MHz phonophoresis using lidocaine on the anterior forearm following 5- and 10-min interventions. DESIGN: This was a crossover study in a laboratory involving 22 healthy participants (13 women, 9 men; age, 23.0 ± 3.2 yrs; height, 169.1 ± 7.2 cm; weight, 70.9 ± 13.9 kg). All subjects received four interventions on four different days: (1) 1.5 W/cm, 100% duty cycle with lidocaine for 5 mins (short); (2) 1.5 W/cm, 50% duty cycle with lidocaine for 10 mins (long); (3) no ultrasound for 10 mins with lidocaine gel (lidocaine sham); and (4) no ultrasound for 10 mins with ultrasound gel (true sham). Skin sensation was measured for analysis. The main outcome measures were Semmes-Weinstein Monofilament (SWM) scores, with higher scores indicating less sensitivity. RESULTS: There was a significant time main effect for SWM scores (P < 0.001). Baseline SWM scores were the lowest (3.00 ± .53; P ≤ 0.006) and post-SWM scores (0 mins) were the highest (3.63 ± .44; P < 0.001), indicating an anesthetic effect at this time. CONCLUSIONS: Neither the long nor the short treatment decreased skin sensation compared with sham conditions. All interventions resulted in decreased skin sensation when comparing baseline SWM scores to all posttreatment scores. Phonophoresis with lidocaine did not result in an enhanced anaesthetic effect on human subjects.

Electrode type and placement configuration for quadriceps activation evaluation.

CONTEXT: The ability to accurately estimate quadriceps voluntary activation is an important tool for assessing neuromuscular function after a variety of knee injuries. Different techniques have been used to assess quadriceps volitional activation, including various stimulating electrode types and electrode configurations, yet the optimal electrode types and configurations for depolarizing motor units in the attempt to assess muscle activation are unknown. OBJECTIVE: To determine whether stimulating electrode type and configuration affect quadriceps central activation ratio (CAR) and percentage-of-activation measurements in healthy participants. DESIGN: Crossover study. SETTING: Research laboratory. PATIENTS AND OTHER PARTICIPANTS: Twenty participants (13 men, 7 women; age = 26 ± 5.3 years, height = 173.85 ± 7.3 cm, mass = 77.37 ± 16 kg) volunteered. INTERVENTION(S): All participants performed 4 counter-balanced muscle activation tests incorporating 2 different electrode types (self-adhesive, carbon-impregnated) and 2 electrode configurations (vastus, rectus). MAIN OUTCOME MEASURE(S): Quadriceps activation was calculated with the CAR and percentage-of-activation equations, which were derived from superimposed burst and resting torque measurements. RESULTS: No differences were found between conditions for CAR and percentage-of-activation measurements, whereas resting twitch torque was higher in the rectus configuration for both self-adhesive (216 ± 66.98 Nm) and carbon-impregnated (209.1 ± 68.22 Nm) electrodes than in the vastus configuration (209.5 ± 65.5 Nm and 204 ± 62.7 Nm, respectively) for these electrode types (F(1,19) = 4.87, P = .04). In addition, resting twitch torque was greater for both electrode configurations with self-adhesive electrodes than with carbon-impregnated electrodes (F(1,19) = 9.33, P = .007). Bland-Altman plots revealed acceptable mean differences for agreement between electrode type and configuration for CAR and percentage of activation, but limits of agreement were wide. CONCLUSIONS: Although these electrode configurations and types might not necessarily be able to be used interchangeably, differences in electrode type and configuration did not seem to affect CAR and percentage-of-activation outcome measures.

No Difference in Transverse Abdominis Activation Ratio between Healthy and Asymptomatic Low Back Pain Patients during Therapeutic Exercise.

Dysfunction of the transverse abdominis (TrA) has been associated with LBP. Several therapeutic exercises are prescribed to help target the TrA. Rehabilitative ultrasound imaging (RUSI) is used to capture activation of the TrA during exercise. The purpose was to examine TrA activation during the ADIM and quadruped exercises between healthy and nonsymptomatic LBP patients. We instructed the subjects how to perform the exercises and measured muscle thickness of the TrA at rest and during the exercises using RUSI. This allowed us to calculate TrA activation ratio during these exercises. We found no significant differences between activation ratios of the two groups during either exercise; however TrA activation during the ADIM was higher than the quadruped exercise. These exercises were capable of activating the TrA, which may be in part due to the verbal instruction they received. These exercises could be used during prevention or rehabilitation programs, since the TrA is activated.