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Context: The aim of this study was to analyze the muscle activity of the hamstring muscles and the lateral gastrocnemius during different variants of the single-leg bridge (SLB) in futsal players. Design: Cross-sectional study. Methods: Twenty-two futsal players (age = 24.8 [3.9] y) volunteered to participate in this study. The participants performed 3 variations of the SLB with the knee flexed at 45°. The first position was performed with the ankle in plantar position with flat support, the second with the ankle in dorsiflexion (DF) with heel support, and the third with the ankle in DF and external rotation (ER) with heel support. The Wilcoxon rank-sum test assessed the difference between variables for samples with the rank-biserial correlation effect size. Spearman correlation coefficients were used to examine the associations of the percentage maximal voluntary isometric contraction for each muscle with peak force and rate of force development with 3 different variances of the SLB. Results: The variation of ankle DF and ER with heel support generated higher muscle activity in BF in concentric (P<.01, effect size [ES] = -0.613); isometric (P<.042, ES = -0.494); and eccentric (P<.005, ES = -0.668) contraction than ankle DF with heel support. In contrast, the variation of ankle DF and ER with heel support generated fewer muscle activity in lateral gastrocnemius in concentric (P < .001, ES = 0.779); isometric (P < .003, ES = 0.708); and eccentric (P < .014, ES = 0.589) contraction than ankle DF with heel support. Conclusions: The position of DF and ER was the best position in SLB to train the BF. It could be convenient to start rehabilitation of the BF with flat foot postition or ankle in DF with heel support and progress with the position of the ankle in DF and ER with heel support. [ABSTRACT FROM AUTHOR]

Context: Whole-body vibration (WBV) training improves muscle strength and balance. Few studies have focused on the effects of WBV frequencies below 30 Hz. We aimed to investigate the effect of low-frequency WBV training on muscle activity, fatigue recovery, and oxygen consumption (VO2). Design: Prospective single-group, repeated-measures study. Methods: In this controlled laboratory setting study, 20 healthy adults (age 23.26 [1.66] y) performed half squats at 0, 4, 6, 8, 12, 16, 20, 24, and 30-Hz WBV. Muscle activity was evaluated using the root mean square and peak electromyography amplitude of 6 muscles (iliocostalis, rectus abdominis, rectus femoris, biceps femoris, tibialis anterior, and gastrocnemius) obtained via surface electromyography. VO2 was measured during the squats using a gas analyzer, and fatigue recovery was evaluated using measurements of lactate after the squats and after a recovery period. Statistical significance was set at P < .05, and analysis of variance was conducted to determine differences in muscle activity, fatigue, recovery, and VO2, with post hoc analyses as appropriate. Results: Of the 6 muscles measured, the muscle activity of the gastrocnemius alone significantly increased from 0 Hz at 4, 8, 12, 16, 24, and 30 Hz based on the root mean square values and at 4, 8, 12, and 30 Hz based on the peak electromyography amplitude values. There were no significant differences in the other muscles. There were no significant differences in VO2 or in lactate levels. Conclusions: Low-frequency WBV during squat exercises significantly increased the activity of the gastrocnemius medialis only at specific frequencies in healthy young adults. Low-frequency WBV is safe and has the potential to increase muscle activity. [ABSTRACT FROM AUTHOR]

Context: Dynamic balance exercises are commonly utilized during ankle sprain and chronic ankle instability (CAI) rehabilitation. Blood flow restriction (BFR) has been used to enhance muscle activity during exercise and improve outcomes of traditional rehabilitation exercises in clinical populations. Objective: Examine the effects of BFR on lower-extremity muscle activation during dynamic balance exercises in individuals with CAI. Design: Crossover study design. Setting: Laboratory. Patients or Other Participants: Twenty-five (N = 25) young adults with a history of CAI. Interventions: Participants performed dynamic balance reaching exercises during 2 randomized order conditions, BFR, and control. For each condition, participants performed 2 trials of balance exercises. Each trial included 4 sets (30 × 15 × 15 × 15) of reaches in anterior, posteromedial, and posterolateral directions. For the BFR condition, the authors placed a cuff around the proximal thigh at 80% of arterial occlusion pressure. For the control condition, no cuff was worn. Main Outcome Measure(s): The authors recorded normalized electromyography muscle activation of the vastus lateralis, soleus, tibialis anterior, and fibularis longus during balance exercise trials and recorded participants' ratings of perceived postural instability and exertion after each trial of balance exercises. Results: The authors observed greater vastus lateralis (P <.001, d = 0.86 [0.28 to 1.44]) and soleus (P =.03, d = 0.32 [−0.24 to 0.87]) muscle activation during balance exercises with BFR than control. The authors observed no differences in tibialis anterior (P =.33, d = 0.09 [−0.46 to 0.65]) or fibularis longus (P =.13, d = 0.06 [−0.50 to 0.61]) muscle activation between the conditions. The authors observed greater ratings of perceived postural instability (P =.004) and exertion (P <.001) during balance exercises with BFR than control. Conclusions: Individuals with CAI demonstrated large increases in vastus lateralis and small increases in soleus muscle activation during dynamic balance exercises with BFR. The BFR had no effect on fibularis longus and tibialis anterior muscle activation. Individuals with CAI perceived greater postural instability and exertion during dynamic balance exercises with BFR. [ABSTRACT FROM AUTHOR]

Context: Chronic ankle instability is documented to be followed by a recurrence of giving away episodes due to impairments in mechanical support. The application of ankle Kinesiotaping (KT) as a therapeutic intervention has been increasingly raised among athletes and physiotherapists. Objectives: This study aimed to investigate the impacts of ankle KT on the lower-limb kinematics, kinetics, dynamic balance, and muscle activity of college athletes with chronic ankle instability. Design: A crossover study design. Participants: Twenty-eight college athletes with chronic ankle sprain (11 females and 17 males, 23.46 [2.65] y, 175.36 [11.49] cm, 70.12 [14.11] kg) participated in this study. Setting: The participants executed 3 single-leg drop landings under nontaped and ankle Kinesio-taped conditions. Ankle, knee, and hip kinematics, kinetics, and dynamic balance status and the lateral gastrocnemius, medial gastrocnemius, tibialis anterior, and peroneus longus muscle activity were recorded and analyzed. Results: The application of ankle KT decreased ankle joint range of motion (P =.039) and angular velocities (P =.044) in the sagittal plane, ground reaction force rate of loading (P =.019), and mediolateral time to stability (P =.035). The lateral gastrocnemius (0.002) and peroneus longus (0.046) activity amplitudes also experienced a significant decrease after initial ground contact when the participants' ankles were taped, while the application of ankle KT resulted in an increase in the peroneus longus (0.014) activity amplitudes before initial ground contact. Conclusions: Ankle lateral supports provided by KT potentially decreases mechanical stresses applied to the lower limbs, aids in dynamic balance, and lowers calf muscle energy consumption; therefore, it could be offered as a suitable supportive means for acute usage in athletes with chronic ankle instability. [ABSTRACT FROM AUTHOR]

Context: The research on the change in properties of the lower leg muscles by different intensity sinusoidal vertical whole-body vibration ( SV - WBV ) exposures has not yet been investigated. Objective: The purpose of this study was to determine effect of a 20-minute different intensity SV-WBV application to the ankle plantar flexor and dorsiflexor muscles properties and hamstring flexibility. Design: Prospective preintervention -postintervention design. Setting: Physiotherapy department. Participants: A total of 50 recreationally active collegeaged individuals with no history of a lower leg injury volunteered. Interventions: The SV-WBV was applied throughout the session with an amplitude of 2 to 4 mm and a frequency of 25 Hz in moderate-intensity vibration group and 40 Hz in a vigorousintensity vibration group . Main Outcome Measures : The gastrocnemius and tibialis anterior muscle tone was assessed with MyotonPRO, and the strength evaluation was made on the same lower leg muscles using hand-held dynamometer. The sit and reach test was used for the lower leg flexibility evaluation. Results: The gastrocnemius muscle tone decreased on the right side (d = 0.643, P = .01) and increased on the left (d= 0.593, P = .04) when vigorous-intensity vibration was applied. Bilateral gastrocnemius muscle strength did not change in both groups (P >.05). Without differences between groups, bilateral tibialis anterior muscle strength increased in both groups (P < .01). B ilateral gastrocnemius and tibialis anterior muscle tone did not change in the moderate-intensity vibration group (P> .05). Flexibility increased in both groups (P < . 01 ); however, there was no statistically significant difference between the groups ( d = 0 . 169, P = . 55 ). Conclusions: According to study results, if SV-WBV is to be used in hamstring flexibility or ankle dorsiflexor muscle strengthening, both vibration exposures should be preferred. Different vibration programs could be proposed to increase ankle plantar Rexor muscle strength in the acute results. Vigorous-intensity vibration exposure is effective in altering ankle plantar flexor muscle tone, but it is important to be aware of the differences between the lower legs. [ABSTRACT FROM AUTHOR]

Context: Recently, a few papers have suggested that tissue flossing (TF) acutely improves range of motion (ROM) and neuromuscular performance. However, the effects of TF on muscle contractile properties are yet to be defined. Objective: To investigate the acute effects of TF on ankle ROM and associated muscle gastrocnemius medialis displacement and contraction time assessed with tensiomyography. Design: Crossover design in a single session. Setting: University laboratory. Participants: Thirty recreationally trained volunteers (age 23.00 [4.51] y). Intervention: Active ankle plantar flexion and dorsiflexion were performed for the duration of 2 minutes (3 sets, 2-min rest between sets), while a randomly selected ankle was wrapped using TF elastic band (BAND) and the other ankle served as a control condition (CON). Main outcome measures: Participants performed an active ankle plantar flexion and dorsiflexion ROM test and muscle gastrocnemius medialis tensiomyography displacement and contraction time measurement pre, 5, 15, 30, and 45 minutes after the floss band application. Results: There were no statistically significant differences between BAND and CON conditions (active ankle plantar flexion ROM: P = .09; active ankle dorsiflexion ROM: P = .85); however, all ROM measurements were associated with medium or large effect sizes in favor of BAND compared with CON. No significant changes were observed in the tensiomyography parameters. Conclusions: The results of this study suggest that TF applied to the ankle is a valid method to increase ROM and at the same time maintaining muscular stiffness. [ABSTRACT FROM AUTHOR]

Context: Elastic taping has been widely used for either to facilitate or to inhibit muscle contraction. The efficacy of elastic taping is allegedly ascribed to physiological mechanisms related to subcutaneous tissue and muscle stimulation as a result of tape tension and direction. However, the underlying mechanisms that support the use of elastic taping are still unclear. Objective: To investigate changes in electrophysiological responses after 48 hours of tape application in different directions on the calf muscles of healthy individuals. Design: Within-subjects design. Setting: Research laboratory. Participants: Twenty-seven physically active males (age 18.0 [4.2] y, height 1.65 [0.07] m, body mass 62.3 [10.3] kg) participated. Interventions: Soleus H-reflex responses were evoked through stimulation of the tibial posterior nerve with 2- to 4-second interval between stimuli (32 sweeps) for each condition (baseline: without tape; facilitation: tape applied from muscle origin to insertion; inhibition: tape applied from muscle insertion to origin). Main outcome measures: The H-reflex amplitude values were normalized by the maximal direct response (Mmax). Parameters were estimated from a sigmoidal fit of the H-reflex recruitment curve (ascending limb). Results: No significant differences were found for the parameters derived from the recruitment curve of the H-reflex among the conditions (P > .05). Conclusions: The authors' findings showed that, irrespective of the direction of tape application, the elastic tape applied over the triceps surae does not generate any significant alteration on the excitability of the reflex pathway for different subpopulations of motor units. The authors therefore suggest a re-examination of the current recommendations on taping direction in clinical and sports activities. [ABSTRACT FROM AUTHOR]

Context: Several studies have reported that self-massage using a foam roller (FR) increased joint range of motion (ROM) immediately. However, the mechanism of increasing ROM by the FR intervention has not been elucidated. Objective: To clarify the mechanism by investigating properties and morphological changes of muscles targeted by the FR intervention. Design: An interventional study. Setting: An athletic training laboratory. Participants: Ten male college volunteers with no injuries in their lower limbs (mean [SD]: age 23.8 [3.2] y, height 173.2 [4.9] cm, weight 69.5 [8.6] kg). Intervention: The FR intervention on the right plantar flexors for 3 minutes. Main Outcome Measures: Maximum ankle ROM, muscle hardness, and fascicle length of the gastrocnemius muscle at the neutral (0°), maximum dorsiflexion, and maximum plantar flexion positions. All measurements were conducted before (PRE) and after (POST) the FR intervention. Results: Dorsiflexion ROM increased significantly at POST (PRE: 13.6° [8.0°], POST: 16.6° [8.4°]; P <.001), although plantar flexion ROM did not change significantly between PRE and POST (PRE: 40.0° [6.1°], POST: 41.1° [4.9°]). There was no significant difference in muscle hardness and fascicle length between PRE and POST in any of the angles. Conclusions: Dorsiflexion ROM increased significantly by the FR intervention in the present study; however, muscle hardness and fascicle length did not change. FR may affect not only the muscle but also the fascia, tendon, and muscle-tendon unit. The FR protocol of the present study can be applied in clinical situations, because it was found to be effective to increase ROM. [ABSTRACT FROM AUTHOR]

Context: Lower-extremity stress fractures (SFx) are a common occurrence during load-bearing activities of jumping and landing. To detect biomechanical changes during jumping postinjury, a fatigue model could be used. Objective: To evaluate muscle activation in the lower leg and tibial accelerations (TAs) prefatigue to postfatigue following a jumping task in those with and without a history of SFx. Design: Repeated-measures. Setting: Athletic Training Research Lab. Participants: A total of 30 active college-aged students with and without a history of lower-extremity (leg or foot) SFx (15 males and 15 females; 21.5 [5.04] y, height = 173.5 [12.7] cm, weight = 72.65 [16.4] kg). Intervention: A maximal vertical jump on one leg 3 times with arms folded across the chest prefatigue to postfatigue was performed. Fatigue protocol was standing heel raises on a custom-built platform at a pace controlled by a metronome until task failure was reached. Legs were tested using a randomized testing order. Electromyographic (EMG) surface electrodes were placed on the medial gastrocnemius, soleus, and tibialis anterior following a standardized placement protocol. A triaxial accelerometer was attached to the proximal anteromedial surface of the tibia. Main Outcome Measures: Linear envelopes of the medial gastrocnemius, soleus, and tibialis anterior and peak accelerations (resultant acceleration takeoff and landing).Results: Significant interaction for leg × test for tibialis anterior with a posttest difference between SFx and control (P =.05). There were decreases in EMG linear envelope following fatigue for medial gastrocnemius (P <.01) and tibialis anterior (P =.12) pretest to posttest. At takeoff, TA was greater in the SFx contralateral leg in comparison with the control leg (P =.04). At landing, TA was greater in posttest (P <.01) and in the SFx leg compared with SFx contralateral (P =.14). Conclusion: A decrease in muscle activity and an increase in TA following fatigue were noted for all subjects but especially for those with a history of SFx. [ABSTRACT FROM AUTHOR]

Context: Rest, ice, compression, and elevation are commonly recommended immediately after injury. Traditionally, ice bag (IB) with elastic wrap compression has been utilized; however, recently intermittent cryocompression units are being used. Limited research has evaluated tissue temperature decreases with intermittent cryocompression units. Objective: Evaluate magnitude of muscle and skin cooling. Design: Repeated-measures counterbalanced study. Setting: University research laboratory. Patients or OtherParticipants: Twelve healthy college-aged participants (4 males and 8 females; age = 23.08 [1.93] y; height = 171.66 [9.47] cm; mass = 73.67 [13.46] kg; subcutaneous thickness = 0.90 [0.35] cm) without compromised circulation or injury. Intervention(s): Salted IB, GameReady (GR), and PowerPlay-ice bag (PP-ice) were applied to the posterior aspect of the nondominant calf for 30 minutes; participants underwent each treatment in counterbalanced order. Main Outcome Measure(s): Muscle temperature measured via 21-gauge catheter thermocouple; skin temperature measured via a surface thermocouple. Temperatures were recorded at baseline and during a 30-minute treatment. Correlations were evaluated between muscle and skin temperatures. Results: Nonsignificant treatment × time interaction and nonsignificant main effect of treatment for intramuscular cooling. Mean Decrease From Baseline: IB, 6.4°C (±2.8); GR, 5.4°C (±1.1); PP-ice, 4.8°C (±2.8). Nonsignificant treatment × time interaction for skin cooling (F20,200 = 1.440, P =.65, η p 2 =.346 , and observed β = 0.773), but significant main effect for treatment (F10,100 = 5.279, P =.03, η p 2 =.883 , and observed β = 1.00). Mean Decrease From Baseline: IB, 17.0°C; GR, 16.4°C; PP-ice, 14.6°C. No significant correlation between intramuscular and skin temperatures in any condition at any time point. No significant correlation between adipose tissue thickness and maximum temperature decrease with any modality. Conclusions: Salted IB with elastic wrap compression, GR, and PP-ice produced equivalent intramuscular temperature decreases during the treatment period. [ABSTRACT FROM AUTHOR]

Context: Self-myofascial release (SMR) is an intervention popularly used by rehabilitation, fitness, and sports professionals to improve recovery and performance. In SMR, the athlete/patient applies pressure to the muscle and fascia using various tools, such as balls, rods, foam rolls, and massagers. Objective: This study aimed to evaluate the acute effect of 2 SMR protocols (short term and long term) of the posterior thigh and calf muscles on hip and ankle range of motion (ROM) in physically active men. Participants: A total of 14 adult males (24.9 [3.2] y, 77.2 [13.2] kg, and 1.75 [0.06] m) who exercise regularly (at least twice a week, 45 min per session) participated in this study. Interventions: Participants performed a short-term SMR protocol (2 × 10 repetitions, SSMR) and a long-term SMR protocol (2 × 20 repetitions, LSMR) of the posterior thigh (using a foam roller) and calf (using a massage stick) muscles in counterbalanced order, on 2 different days with a 48-hour interval. Main Outcome Measures: Ankle dorsiflexion and hip-flexion ROM, evaluated at 5 moments: pre- and post-SSMR, pre- and post-LSMR, and in the control condition, which was always performed at the first visit. Results: The SMR promoted significant gains for both dorsiflexion (F1,13 =202.67, P <.001, η p 2 =.94) and hip flexion (F1,13 = 66.46, P <.001, η p 2 =.84), regardless of the protocol and limb analyzed. The average increase for both limbs corresponded, approximately, to 11% for ankle dorsiflexion and to 6% for and in hip flexion. Conclusions: The results suggest that SMR of the posterior thigh and calf muscles acutely increases the ROM of both hip flexion and ankle dorsiflexion and that duplicating the SMR volume from 10 to 20 repetitions per set seems not to promote additional gains. [ABSTRACT FROM AUTHOR]

Context: Delayed onset muscle soreness is one of the most common reasons for impaired muscle performance in sports and is associated with reduced muscle strength and frequently observed both in professional and recreational athletes. Objective: To emphasize the diagnostic value of acoustic radiation force impulse (ARFI) in imaging of delayed onset muscle soreness by comparing findings with high-resolution 3T magnetic resonance imaging T2-weighted sequences. Design: Case series. Setting: Laboratory environment. Participants: Fifteen healthy students (7 females and 8 males; mean [SD]: age 24 [4] y, height 178 [10] cm, body weight 67 [12] kg). Main Outcome Measures: ARFI values, represented as shear wave velocities of the gastrocnemius muscle and soleus muscle, as well as conventional ultrasound, high-resolution 3T magnetic resonance imaging, creatine kinase activity, extension range of the ankle joint, calf circumference, and muscle soreness were assessed before (baseline) and 60 hours after (postintervention) a standardized eccentric exercise. Results: ARFI shear wave velocity values of the gastrocnemius muscle revealed a statistically significant decrease of 19.1% between baseline (2.2 [0.26] m/s) and postintervention (1.78 [0.24] m/s); P =.01. At follow-up, the magnetic resonance imaging investigations showed intramuscular edema for the gastrocnemius muscle in all participants corresponding to a significant raise in T2 signal intensity (P =.001) and in T2-time values (P =.004). Conclusions: ARFI elastography seems to be an additional sensitive diagnostic modality in the diagnostic workup of delayed onset muscle soreness. Intramuscular shear wave velocities could represent an additional imaging marker for the assessment and monitoring of ultrastructural muscle injuries and therefore be helpful for individual training composition in elite sports. [ABSTRACT FROM AUTHOR]

Context: Kinesio tape (KT) is a widely used intervention in the fields of sports and rehabilitation. However, its effects on lower-extremity behavior during functional activities are not entirely known. Objective: To test the hypothesis that application of KT can change performance and vertical stiffness (VS) during the countermovement jump (CMJ) before and after a fatigue protocol. Design: A predesign and postdesign to study the effect of KT in 2 situations, prefatigue and postfatigue. In each fatiguing condition, there were 2 conditions with and without KT application on the gastrocnemius muscle. Setting: Biomechanics laboratory. Participants: Fifty healthy, nonathlete participants (26 females and 24 males). Interventions: KT application on the gastrocnemius muscle and a fatigue protocol to induce fatigue in plantar flexor muscles. Main Outcome Measures: Various jumping parameters, including jump height, maximum force, maximum power, rate of force development, eccentric lower-limb stiffness, and VS, were calculated using the vertical ground reaction force data. Eccentric lower-limb stiffness and VS were calculated using a mass-spring model. The studied variables can present lower-extremity elastic behavior and performance during CMJ. Results: The results of a 2-way repeated-measures analysis of variance showed no significant effect for KT application. Fatigue resulted in lower values of jump height, maximum power, and VS. Moreover, male subjects showed greater values of jump height, maximum force, and maximum power than did females. Conclusions: The main finding of this study was that gastrocnemius KT has no effect on performance or elastic behavior of the lower-extremity during CMJ. Moreover, KT cannot reduce the adverse effect of fatigue in a functional activity such as CMJ. It seems that gastrocnemius KT is not effective for demanding activities. [ABSTRACT FROM AUTHOR]

Context: It has been reported that there is a high rate of Achilles tendon injury among kendo athletes. For protection and to support the area, kendo athletes habitually use taping during practice or games. Objective: To investigate the effect of various taping techniques on injury prevention and functional performance in kendo athletes. Design: Case-control study. Setting: Laboratory. Participants: 15 University Kendo Team athletes with at least 2 y kendo experience. Main Outcome Measures: Athletes completed 5 stepping backwards and striking cycles under 4 taping conditions: no taping, athletic taping of ankle joint (AT-Ankle), athletic taping of Achilles tendon (AT-Achilles), and Kinesio-Tex taping of Achilles tendon (KT-Achilles). Jump distance, lower limb angular motion, left foot-ground contact time, Achilles tendon force (ATF), and soleus and medial gastrocnemius muscle activities were measured. Results: Lowest peak ATF was found in AT-Achilles during heel-down phase, with statistically significant difference from KT-Achilles peak force. Significant decline of soleus muscle electromyography amplitude was also found when compared to no taping during heel-down phase and other conditions during pushing phase. Conversely, KT-Achilles showed significant decrease in foot-ground contact time compared with no taping and greater ankle range of motion than in AT-Ankle. Conclusion: To protect the Achilles tendon, AT-Achilles taping is recommended since it tends to decrease ATF. Conversely, to enhance athlete performance, we recommend KT-Achilles taping to speed up kendo striking motion. However, the Achilles tendon must withstand greatest forces concurrently. This finding implies that AT-Achilles taping can protect the injured Achilles tendon and KT-Achilles taping can enhance performance on the kendo striking motion. [ABSTRACT FROM AUTHOR]

Context: Therapeutic ultrasound clinical parameters are provided in many modality textbooks based on research performed with the Omnisound brand. Literature exists to support variability in heating rates with different manufacturers. It is unknown if the Dynatron Solaris heats at rates consistent with textbook recommendations. Objective: Determine the rate of tissue-temperature increases in the medial triceps surae with the Dynatron Solaris® 708 ultrasound unit. Design: 3 X 13 repeated measures. Independent variables were tissue depth (1.0, 1.75, and 2.5 cm) and time (13 time periods throughout the treatment). Setting: Research laboratory. Participants: 30 healthy volunteers (female = 11, male = 19; age 21.30 ±1.95 y; adipose thickness = 0.54 ±0.15 cm). Intervention: Three thermocouples were inserted into the medial triceps surae at 1.0, 1.75, and 2.5-cm depths. A continuous 3-MHz, 1.0-W/cm² for 20 minutes ultrasound treatment was performed with a Dynatron Solaris 708 machine. Main Outcome Measures: Intramuscular tissue-temperature increases at each depth throughout the 20-min treatment. Results: There was a significant main effect of depth (F2,52 = 29.76, P < 0.001) and time (F12,312 = 181.59, P < .001) and a significant interaction between times and depths (F24,624 = 15.49, P< .001). The 1.0-cm depth increased 4.22± 1.58°C in 6 min (0.70°C/min rate), the 1.75-cm depth increased 3.93 ± 1.94°C in 10 min (0.39°C/min rate), and the 2.5-cm depth increased 3.60±1.86°C in 20 min (0.18°C/min rate). Conclusions: The rate of tissue- temperature increase varied at each depth and the 1.0-cm depth was the only rate similar to textbooks. Clinicians will not reach tissue-temperature goals using Omnisound textbook parameters on the Dynatron Solaris 708 at depths greater than 1.0 cm, which may affect clinicians, educators, and state-certification exams. [ABSTRACT FROM AUTHOR]

Context: Static stretching (SS) is commonly performed in a warm-up routine to increase joint range of motion (ROM) and to decrease muscle stiffness. However, the time course of changes in ankle-dorsiflexion (DF) ROM and muscle stiffness during a routine SS program is unclear. Objective: To investigate changes in ankle-DF ROM, passive torque at DF ROM, and muscle stiffness during a routine SS program performed 3 times weekly for 4 wk. Design: A quasi-randomized controlled-trial design. Participants: The subjects comprised 24 male volunteers (age 23.8 ± 2.3 y, height 172.0 ± 4.3 cm, body mass 63.1 ± 4.5 kg) randomly assigned to either a group performing a 4-wk stretching program (SS group) or a control group. Main Outcome Measures: DF ROM, passive torque, and muscle stiffness were measured during passive ankle dorsiflexion in both groups using a dynamometer and ultrasonography once weekly during the 4-wk intervention period. Results: In the SS group, DF ROM and passive torque at DF ROM significantly increased after 2, 3, and 4 wk compared with the initial measurements. Muscle stiffness also decreased significantly after 3 and 4 wk in the SS group. However, there were no significant changes in the control group. Conclusions: Based on these results, the SS program effectively increased DF ROM and decreased muscle stiffness. Furthermore, an SS program of more than 2 wk duration effectively increased DF ROM and changed the stretch tolerance, and an SS program more than 3 wk in duration effectively decreased muscle stiffness. [ABSTRACT FROM AUTHOR]

Context: Regular performance (~2x/wk) of Nordic curls has been shown to increase hamstring strength and reduce the risk of hamstring strain injury, although no consensus on ankle position has been provided. Objective: To compare the effects of performing Nordic curls, with the ankle in a dorsiflexed (DF) or plantar-flexed (PF) position, on muscle activity of the biceps femoris (BF) and medial gastrocnemius (MG). Participants: 15 male college athletes (age 22.6 ± 2.1 y, height 1.78 ± 0.06 m, body mass 88.75 ± 8.95 kg). Design: A repeated-measures design was used, with participants performing 2 sets of 3 repetitions of both variations of Nordic curls, while muscle activity was assessed via surface electromyography (EMG) of the BF and MG. Comparisons of muscle activity were made by examining the normalized EMG data as the percentage of their maximum voluntary isometric contraction. Results: Paired-samples t test revealed no significant difference in normalized muscle activity of the BF (124.5% ± 6.2% vs 128.1 ± 5.0%, P > .05, Cohen d = 0.64, power = .996) or MG (82.1% ± 3.9% vs 83.5 ± 4.8%, P > .05, Cohen d = 0.32, power = .947) during the Nordic curls in a PF or DF position, respectively. Conclusion: Ankle position does not influence muscle activity during the Nordic curl; however, performance of Nordic curls with the ankle in a DF position may be preferential, as this replicates the ankle position during terminal leg swing during running, which tends to be the point at which hamstring strains have been reported. [ABSTRACT FROM AUTHOR]

Context: Muscle fatigue and acute muscle soreness occur after exercise. Application of a local vibration intervention may reduce the consequences of fatigue and soreness. Objective: To examine the effects of a local vibration intervention after a bout of exercise on balance, power, and self-reported pain. Design: Single-blind crossover study. Setting: Laboratory. Participants: 19 healthy, moderately active subjects. Interventions: After a 30-min bout of full-body exercise, subjects received either an active or a sham vibration intervention. The active vibration intervention was performed bilaterally over the muscle bellies of the triceps surae, quadriceps, hamstrings, and gluteals. At least 1 wk later, subjects repeated the bout, receiving the other vibration intervention. Main Outcome Measures: Static balance, dynamic balance, power, and self-reported pain were measured at baseline, after the vibration intervention, and 24 h post-exercise. Results: After the bout of exercise, subjects had reduced static and dynamic balance and increased self-reported pain regardless of vibration intervention. There were no differences between outcome measures between the active and sham vibration conditions. Conclusions: The local vibration intervention did not affect balance, power, or self-reported pain. [ABSTRACT FROM AUTHOR]

Context: Achilles tendons (ATs) adapt to increased loading generated by long-term adoption of a minimalist shoe running style. There may be difference in the chronology and extent of adaptation between the sexes. Objective: To learn the chronology of AT adaptations in female and male runners who transitioned to a minimalist running style through a planned, progressive 12-wk transition program. Design: Prospective cohort study of well-trained, traditionally shod runners who transitioned to minimalist shoe running. Setting: Repeated laboratory assessment at baseline and 3, 12, and 24 wk after initiating transition program. Participants: Fifteen women and 7 men (of 29 enrolled) completed the study. Main Outcome Measures: The authors used diagnostic ultrasound and isokinetic dynamometry to generate a force elongation curve and its derivatives at each time point. Results: Greater adaptations were observed in men than in women, with men generating more force and having greater increases in CSA, stiffness, and Young's modulus and less elongation after 12 wk of training. Conclusion: Men demonstrated changes in AT properties that were consistent with increased loading of the triceps surae during exercise. The women demonstrated far smaller changes. Further investigation is warranted to understand when adaptations may occur in women and the implications of altered AT mechanical properties for performance and injury risk. [ABSTRACT FROM AUTHOR]

Context: Eccentric exercises are increasingly being used to treat lower-limb musculoskeletal conditions such as Achilles tendinopathy. Despite widespread clinical application and documented efficacy, mechanisms underpinning clinical benefit remain unclear. Positive adaptations in motor performance are a potential mechanism. Objective: To investigate how an eccentric loading intervention influences measures of stretch-shortening-cycle (SSC) behavior during a hopping task. Design: Within-subjects repeated-measures observational study. Setting: University motion-analysis laboratory. Participants: Healthy adults. Interventions: A single intervention of 5 sets of 10 eccentric plantar-flexion contractions at 6 repetitions maximum using a commercial seated calf-raise machine. Main Outcome Measures: Lower-limb stiffness, sagittal-plane ankle kinematics, and temporal muscle activity of the agonist (soleus) and antagonist (tibialis anterior) muscles, measured during submaximal hopping on a custom-built sledge-jump system. Results: Eccentric loading altered ankle kinematics during submaximal hopping; peak angle shifted to a less dorsiflexed position by 2.9° and ankle angle precontact shifted by 4.4° (P < .001). Lower-limb stiffness increased from 5.9 to 6.8 N/m (P < .001), while surface EMG measures of soleus occurred 14--44% earlier (P < .001) after the loading intervention. Conclusions: These findings suggest that eccentric loading alters SSC behavior in a manner reflective of improved motor performance. Decreased ankle excursion, increased lower-limb stiffness, and alterations in motor control may represent a positive adaptive response to eccentric loading. These findings support the theory that mechanisms underpinning eccentric loading for tendinopathy may in part be due to improved "buffering" of the tendon by the neuromuscular system. [ABSTRACT FROM AUTHOR]

Context: Although knee pain is common, some facets of this pain are unclear. The independent effects (ie, independent from other knee injury or pathology) of knee pain on neural activation of lower-extremity muscles during landing and jumping have not been observed. Objective: To investigate the independent effects of knee pain on lower-extremity muscle (gastrocnemius, vastus medialis, medial hamstrings, gluteus medius, and gluteus maximus) activation amplitude during landing and jumping, performed at 2 different intensities. Design: Laboratory-based, pretest, posttest, repeated-measures design, where all subjects performed both data-collection sessions. Methods: Thirteen able-bodied subjects performed 2 different land and jump tasks (forward and lateral) under 2 different conditions (control and pain), at 2 different intensities (high and low). For the pain condition, experimental knee pain was induced via a hypertonic saline injection into the right infrapatellar fat pad. Functional linear models were used to evaluate the influence of experimental knee pain on muscle-activation amplitude throughout the 2 land and jump tasks. Results: Experimental knee pain independently altered activation for all of the observed muscles during various parts of the 2 different land and jump tasks. These activation alterations were not consistently influenced by task intensity. Conclusion: Experimental knee pain alters activation amplitude of various lower-extremity muscles during landing and jumping. The nature of the alteration varies between muscles, intensities, and phases of the movement (ie, landing and jumping). Generally, experimental knee pain inhibits the gastrocnemius, medial hamstring, and gluteus medius during landing while independently increasing activation of the same muscles during jumping. [ABSTRACT FROM AUTHOR]

Context: Rolling sensations at the ankle are common after injury and represent failure in neural regulation of joint stiffness. However, deficits after ankle injury are variable and strategies for optimizing stiffness may differ across patients. Objective: To determine if ankle stiffness and muscle activation differ between patients with varying history of ankle injury. Patients: Fifty-nine individuals were stratified into healthy (CON, n = 20), functionally unstable (UNS, n = 19), and coper (COP, n = 20) groups. Main Outcome Measures: A 20° supination perturbation was applied to the ankle as position and torque were synchronized with activity of tibialis anterior, peroneus longus, and soleus. Subjects were tested with muscles relaxed, while maintaining 30% muscle activation, and while directed to react and resist the perturbation. Results: No group differences existed for joint stiffness (F = 0.07, P = .993); however, the UNS group had higher soleus and less tibialis anterior activation than the CON group during passive trials (P < .05). In addition, greater early tibialis anterior activation generally predicted higher stiffness in the CON group (P ≤ .03), but greater soleus activity improved stiffness in the UNS group (P = .03). Conclusion: Although previous injury does not affect the ability to stiffen the joint under laboratory conditions, strategies appear to differ. Generally, the COP has decreased muscle activation, whereas the UNS uses greater plantar-flexor activity. The results of this study suggest that clinicians should emphasize correct preparatory muscle activation to improve joint stiffness in injury-rehabilitation efforts. [ABSTRACT FROM AUTHOR]

Context: Despite the widespread use of whole-body vibration (WBV), especially in recent years, its neurophysiological mechanism is still unclear and it is yet to be determined whether acute and short-term WBV exposure produce neurogenic enhancement for agility. Objective: To compare the acute and short-term effects of WBV on the H-reflex-recruitment curve and agility. Design: Cross-over study. Setting: Clinical electrophysiology laboratory. Participants: 20 nonathlete male volunteers (mean age 24.85 ± 3.03 y). Main Outcome Measures: Subjects were randomly divided into 2 groups, H-reflex and agility. In the sham protocol, subjects stood on the turned-off vibration plate while maintaining the semisquat position, and then, after a 2-wk washout, vibration-training sessions were performed in the same position with a frequency of 30 Hz and an amplitude of 3 mm. H-reflex-recruitment curve was recorded and the agility test of a shuttle run was performed before and after the first session and also 48 h after the 11th session in both sham and vibration-training protocols. Results: Acute effects of WBV training caused a significant decrease of threshold amplitude and H-max/M-max (P = .01 and P = .04, respectively). Short-term WBV training significantly decreased the threshold intensity of the soleus H-reflex-recruitment curve (P = .01) and caused a decrease and increase respectively, in the threshold intensity and the area under the recruitment curve. Conclusions: The results suggest an inhibitory effect of acute WBV training on the H-reflex response. [ABSTRACT FROM AUTHOR]

Context: Assessments of skeletal-muscle functional capacity often necessitate maximal contractile effort, which exacerbates muscle fatigue or injury. Tensiomyography (TMG) has been investigated as a means to assess muscle contractile function after fatigue; however, observations have not been contextualized by concurrent physiological measures. Objective: To measure peripheral-fatigue-induced alterations in mechanical and contractile properties of the plantar-flexor muscles through noninvasive TMG concurrently with maximal voluntary contraction (MVC) and passive muscle tension (PMT) to validate TMG as a gauge of peripheral fatigue. Design: Pre- and posttest intervention with control. Setting: University laboratory. Participants: 21 healthy male volunteers. Interventions: Subjects' plantar flexors were tested for TMG parameters, along with MVC and PMT, before and after either a 5-min rest period (control) or a 5-min electrical-stimulation intervention (fatigue). Main Outcome Measures: Temporal (contraction velocity) and spatial (radial displacement) contractile parameters of the gastrocnemius medialis were recorded through TMG. MVC was measured as an indicator of muscle fatigue, and PMT was measured to assess muscle stiffness. Results: Radial displacement demonstrated a fatigue-associated reduction (3.3 ± 1.2 vs 4.0 ± 1.4 mm, P = .031), while contraction velocity remained unaltered. In addition, MVC significantly declined by 122.6 ± 104 N (P < .001) after stimulation (fatigue). PMT was significantly increased after fatigue (139.8 ± 54.3 vs 111.3 ± 44.6 N, P = .007). Conclusions: TMG successfully detected fatigue, evident from reduced MVC, by displaying impaired muscle displacement accompanied by elevated PMT. TMG could be useful in establishing skeletalmuscle fatigue status without exacerbating the functional decrement of the muscle. [ABSTRACT FROM AUTHOR]

Context: Gluteal-muscle strength has been identified as an important component of injury prevention and rehabilitation in several common knee injuries. However, many conventionally prescribed gluteal-strengthening exercises are not performed during dynamic weight-bearing activities, which is when most injuries occur. Objectives: To compare lower-limb muscle-activation patterns between conventional gluteal-strengthening exercises and off-axis elliptical exercises with motorized foot-plate perturbations designed to activate gluteal muscles during dynamic exercise. Evidence Acquisition: Twelve healthy volunteers (26.1 ± 4.7 y) participated in the study. They performed 3 conventional exercises (single-leg squat, forward lunge, and clamshell) and 3 elliptical exercises (regular, while resisting an adduction force, and while resisting an internal-rotation torque). Gluteus medius (GMed) and maximus (GMax), quadriceps, hamstrings, and gastrocnemius muscle activations during each exercise were recorded using surface electromyography (EMG) and normalized to maximal voluntary isometric contraction (MVIC). Evidence Synthesis: Normalized GMed EMG was the highest during the adduction-resistance elliptical exercise (22.4% ± 14.8% MVIC), significantly greater than forward lunge (8.2% ± 3.8% MVIC) and regular elliptical (6.4% ± 2.5% MVIC) and similar to clamshell (19.1% ± 8.8% MVIC) and single-leg squat (18.4% ± 7.9% MVIC). Normalized GMax EMG during adduction-resistance (11.1% ± 7.6% MVIC) and internal-rotation-resistance elliptical (7.4% ± 3.8% MVIC) was significantly greater than regular elliptical (4.4% ± 2.4% MVIC) and was similar to conventional exercises. The single-leg squat required more muscle activation from the quadriceps and gastrocnemius than the elliptical exercises. Conclusions: Off-axis elliptical exercise while resisting an adduction force or internal-rotation torque activates gluteal muscles dynamically while avoiding excessive quadriceps activation during a functional weight-bearing activity compared with conventional gluteal-strengthening exercises. [ABSTRACT FROM AUTHOR]

Context: Spinal-reflexive and corticomotor excitability may have a critical role in altering muscle function needed to stabilize the ankle in people with chronic ankle instability (CAI). Objective: To determine the association between self-reported disability and both spinal-reflexive and corticomotor excitability in people with CAI. Design: Descriptive laboratory study. Setting: Research laboratory. Participants: 30 participants with CAI. Main Outcome Measures: Soleus spinal-reflexive excitability was measured with normalized Hoffmann reflexes (H:M ratio), and corticomotor excitability was measured with transcranial magnetic stimulation and quantified by normalized motor-evoked-potential (MEP) amplitudes at 120% of active motor threshold (120%MEP). Self-reported disability was quantified with the activities-of-daily-living and sport subscales of the Foot and Ankle Ability Measure (FAAM-ADL and FAAM-S). Separate linear Pearson product-moment correlations and nonlinear quadratic correlations were used to determine associations between the neural-excitability and disability variables. Results: Thirty participants were included in the spinal-reflexive-excitability analysis, while only 19 were included in the corticomotor analysis. There was a significant, weak linear association between H:M ratio and FAAM-ADL (R = .39, P = .03) and a nonsignificant, weak linear association between H:M ratio and FAAM-S (R = .36, P = .06). There were significant, moderate quadratic associations between H:M ratio and both FAAM-ADL (R = .48, P = .03) and FAAM-S (R = .50, P = .02). There was a significant, moderate linear association between 120%MEP and FAAM-ADL (R = -.48, P = .04) and a nonsignificant, moderate negative linear association between FAAM-S (R = -.42, P = .07). There was a significant, moderate quadratic association between 120%MEP and FAAM-ADL (R = .57, P = .046) and a significant, strong quadratic correlation between 120%MEP and FAAM-S (R = .71, P = .004). Conclusions: There are significant quadratic associations between self-reported disability and both spinal-reflexive and corticomotor excitability of the soleus. CAI participants with low or high neural excitability present with lower function. [ABSTRACT FROM AUTHOR]

Context: The use of Kinesio Tape among health care professional has grown recently in efforts to efficiently prevent and treat joint injuries. However, limited evidence exists regarding the efficacy of this technique in enhancing joint stability and neuromuscular control. Objective: To determine how Kinesio Tape application to the ankle joint alters forces and muscle activity during a drop-jump maneuver. Design: Single-group pre-test-posttest. Setting: University laboratory. Subjects: 22 healthy adults with no previous history of ankle injury. Interventions: Participants were instrumented with electromyography on the lower-leg muscles as they jumped from a 35-cm platform onto force plates. Test trials were performed without tape (BL), immediately after application of Kinesio Tape to the ankle (KT-I), and after 24 h of continued use (KT-24). Main Outcome Measures: Peak ground-reaction forces (GRFs) and time to peak GRF were compared across taping conditions, and the timing and amplitude of muscle activity from the tibialis anterior, peroneus longus, and lateral gastrocnemius were compared across taping conditions. Results: No significant differences in amplitude or timing of GRFs were observed (P > .05). However, muscle activity was observed to decrease from BL to KT-I in the tibialis anterior (P = .027) and from BL to KT-24 in the PL (P = .022). Conclusions: The data suggest that Kinesio Tape decreases muscle activity in the ankle during a drop-jump maneuver, although no changes in GRFs were observed. This is contrary to the proposed mechanisms of Kinesio Tape. Further research might investigate how this affects participants with a history of injury. [ABSTRACT FROM AUTHOR]

Context: Stretching exercises are commonly prescribed for patients and healthy individuals with limited extensibility of the gastrocnemius muscle. Objective: To determine if individuals demonstrate more dorsiflexion at the ankle/rear foot and less at the midfoot after a gastrocnemius-stretching program with the subtalar joint (STJ) positioned in supination compared with pronation. Design: Randomized controlled trial. Setting: Biomechanical laboratory. Participants: 22 volunteers with current or recent history of lower-extremity cumulative trauma and gastrocnemius tightness (10 women and 4 men, mean age 28 y) randomly assigned to stretching groups with the STJ positioned in either pronation (n = 11) or supination (n = 11). Intervention: 3-wk home gastrocnemius-stretching program using a template to place the subtalar joint in either a pronated or a supinated position. Main Outcome Measures: A 7-camera Vicon motion-analysis system measured ankle/ rear-foot dorsiflexion and midfoot dorsiflexion of all participants during stretching with the STJ positioned in both pronation and supination before and after the 3-wk gastrocnemius-stretching program. Results: A 2-way mixed-model ANOVA revealed a significant interaction (P - .019). At posttest, the group who performed the 3-week stretching program with the STJ positioned in pronation demonstrated more increased ankle/rear-foot dorsiflexion when measured with the STJ in pronation than the group who performed the 3-wk stretching program with the STJ positioned in supination. No significant main effect of stretching group or interaction for dorsiflexion at the midfoot was detected (P = .755 and P = .820. respectively). Conclusion: After a 3-wk gastrocnemius-stretching program, when measuring dorsiflexion with the STJ positioned in supination, the participants who completed a 3-wk gastrocnemius stretching program with the STJ positioned in pronation showed more increased dorsiflexion at the ankle/rear foot than participants who completed the stretching program with the STJ positioned in supination. [ABSTRACT FROM AUTHOR]

Context: Hold-relax stretching (HRS) and static stretching (SS) are commonly used to increase joint range of motion (ROM) and decrease muscle stiffness. However, whether there are differences between acute effects of HRS and SS on end ROM, passive torque, and muscle stiffness is unclear. In addition, any differences between the mechanisms by which HRS and SS lead to an increase in end ROM are unclear. Objective: To compare the acute effects of HRS and SS on the passive properties of the gastrocnemius muscle-tendon unit (MTU), end ROM, passive torque, and muscle stiffness in vivo and to investigate the factors involved in increasing end ROM. Design: Crossover experimental design. Participants: 30 healthy men (21.7 ± 1.2 y) with no history of neuromuscular disease or musculoskeletal injury involving the lower limbs. Intervention: Both HRS and SS of 30 s were repeated 4 times, lasting a total of 2 min. Main Outcome Measures: End ROM, passive torque, and muscle stiffness were measured during passive ankle dorsiflexion using a dynamometer and ultrasonography before and immediately after HRS and SS. Results: The results showed that end ROM and passive torque at end ROM significantly increased immediately after both HRS and SS, whereas muscle stiffness significantly decreased. In addition, the percentage change in passive torque at end ROM on use of the HRS technique was significantly higher than that after use of the SS technique. However, the percentage change in muscle stiffness after SS was significantly higher than that with HRS. Conclusion: These results suggest that both HRS and SS can effectively decrease muscle stiffness of the gastrocnemius MTU and that HRS induces a change in the passive torque at end ROM—ie, sensory perception—rather than changing muscle stiffness. [ABSTRACT FROM AUTHOR]

Context: Focal ankle-joint cooling (FAJC) has been shown to increase Hoffmann (H) reflex amplitudes of select leg muscles while subjects lie prone, but it is unknown whether the neurophysiological cooling effects persist in standing. Objective: To assess the effects of FAJC on H-reflexes of the soleus and fibularis longus during 3 body positions (prone, bipedal, and unipedal stances) in individuals with and without chronic ankle instability (CAI). Design: Crossover. Setting: Laboratory. Participants: 15 young adults with CAI (9 male, 6 female) and 15 healthy controls. Intervention: All subjects received both FAJC and sham treatments on separate days in a randomized order. FAJC was accomplished by applying a 1.5-L plastic bag filled with crushed ice to the ankle for 20 min. Sham treatment involved room-temperature candy corn. Main Outcome Measures: Maximum amplitudes of H-reflexes and motor (M) waves were recorded while subjects lay prone and then stood in quiet bipedal and unipedal stances before and immediately after each treatment. Primary outcome measures were Hmax:Mmax ratios for the soleus and fibularis longus. Three-factor (group x treatment condition x time) repeated-measures ANOVAs and Fisher LSD tests were performed for statistical analyses. Results: Significant interactions of treatment condition by time for prone Hmax:Mmax ratios were found in the soleus (P = .001) and fibularis longus (P = .003). In both muscles, prone Hmax:Mmax ratios moderately increased after FAJC but not after sham treatment. The CAI and healthy groups responded similarly to FAJC. In contrast, there were no significant interactions or main effects in the bipedal and unipedal stances in either muscle (P > .05). Conclusions: FAJC moderately increased H-reflex amplitudes of the soleus and fibularis longus while subjects were prone but not during bipedal or unipedal standing. These results were not different between groups with and without CAI. [ABSTRACT FROM AUTHOR]

Context: The application of kinesio tape (KT) to lower-extremity muscles as an ergogenic aid to improve muscle-strength-related parameters such as jumping is controversial. Objective: To test the hypothesis that the application of KT enhances the jumping performance of healthy uninjured elite female track and field athletes. Design: A double 1-legged jump test was performed before and after the application of blue K-Active tape without traction on the maximally stretched gastrocnemius, hamstrings, rectus femoris, and iliopsoas muscles according to the generally accepted technique. Participants: 18 German elite female track and field athletes (age 21 ± 2 y, height 172 ± 4 cm, body mass 62 ± 5 kg, active time in their sport 13 ± 4 y). Results: Factorial analysis of variance with repeated measures (ANOVA, Bonferroni) revealed no significant differences in jumping performance between the tests (P > .05, d = 0.26). Conclusions: These findings suggest that the application of KT has no influence on jumping performance in healthy, uninjured female elite athletes. The authors do not recommend the use of KT for the purpose of improving jump performance. [ABSTRACT FROM AUTHOR]

CONTEXT: Altered neuromuscular function and decreased dorsiflexion range of motion (DFROM) have been observed in patients with chronic ankle instability (CAI). Joint mobilizations are indicated for restoring DFROM and dynamic postural control, yet it remains unknown if a mobilization can alter neuromuscular excitability in muscles surrounding the ankle. OBJECTIVE: To determine the immediate effects of a Maitland grade III anterior-to-posterior joint mobilization on spinal-reflex and corticospinal excitability in the fibularis longus (FL) and soleus (SOL), DFROM, and dynamic postural control. DESIGN: Single-blinded randomized control trial. SETTING: Research laboratory. PATIENTS: 30 patients with CAI randomized into a mobilization (n = 15) or control (n = 15) group. INTERVENTION: Maitland grade III anterior-to-posterior joint mobilization. MAIN OUTCOME MEASURES: Spinal-reflex excitability was measured with the Hoffmann reflex, while corticospinal excitability was evaluated with transcranial magnetic stimulation. DFROM was measured seated with the knee extended, and dynamic postural control was quantified with the Star Excursion Balance Test. Separate 2 × 2 repeated-measures ANOVAs were performed for each outcome measure. Dependent t tests were used to evaluate individual differences within groups in the presence of significance. RESULTS: Spinal-reflex and corticospinal excitability of the SOL and FL were not altered in the mobilization or control group (P > .05). DFROM increased immediately after the mobilization (P = .05) but not in the control group, while dynamic postural control was unchanged in both groups (P > .05). CONCLUSION: A single joint-mobilization treatment was efficacious at restoring DFROM in participants with CAI; however, excitability of spinal reflex and corticospinal pathways at the ankle and dynamic postural control were unaffected. [ABSTRACT FROM AUTHOR]

BACKGROUND: Body-weight (BW) support during running can be accomplished using deep-water running (DWR; 100% BW support) and a lower-body positive-pressure (LBPP) treadmill. PURPOSE: To compare lower-extremity muscle activity during DWR and running on an LBPP treadmill at matched stride frequency. METHODS: Eight subjects (40 ± 6.5 y, 173 ± 7.2 cm, 66.9 ± 11.7 kg) completed 4 running conditions all at a preferred stride frequency that was determined while running with no support. Two conditions were running on the LBPP treadmill at 60% and 80% of BW, and the other 2 conditions were different DWR styles: high knee (DWR-HK) and cross-country (DWR-CC). Average (AVG) and root-mean-square (RMS) electromyography (rectus femoris, biceps femoris, gastrocnemius, and tibialis anterior) were each compared among conditions (repeated-measures analysis of variance). RESULTS: Results for AVG and RMS variables were identical for statistical tests for each muscle. Rectus femoris electromyography during DWR-HK was lower than that of DWR-CC (P < .05) but not different than either 60% BW or 80% BW (P > .05). Biceps femoris electromyography was less during DWR-HK than DWR-CC (P < .05) but greater during DWR-HK than either BW 60% or BW 80% (P < .05). Neither gastrocnemius nor tibialis anterior electromyography differed between conditions (P > .05). CONCLUSION: Neither the mechanism of BW support nor style of DWR influenced gastrocnemius or tibialis anterior muscle activity during running at the same stride frequency. However, rectus femoris and biceps femoris muscle activity were influenced by not only the mechanism of BW support but also the style of DWR. [ABSTRACT FROM AUTHOR]

Context: Ankle-destabilization devices are rehabilitation tools that may improve neuromuscular control by increasing lower-extremity muscle activation. Their effects should be tested in healthy individuals before being implemented in rehabilitation programs. Objective: To compare EMG activation of lower-extremity muscles during walking while wearing 2 different ankle-destabilization devices. Design: Crossover. Setting: Laboratory. Participants: 15 healthy young adults (5 men, 10 women). Intervention: Surface EMG activity was recorded from the anterior tibialis, peroneus longus, lateral gastrocnemius, rectus femoris, biceps femoris, and gluteus medius as subjects walked on a treadmill shod, with an ankle-destabilization boot (ADB), and an ankle-destabilization sandal (ADS). Main Outcome Measures: Normalized amplitudes 100 ms before and 200 ms after initial heel contact, time of onset activation relative to initial contact, and percent of activation time across the stride cycle were calculated for each muscle in each condition. Results: The precontact amplitudes of the peroneus longus and lateral gastrocnemius and the postcontact amplitudes of the lateral gastrocnemius were significantly greater in the ADB and ADS conditions. In the ADB condition, the rectus femoris and biceps femoris postcontact amplitudes were significantly greater than shod. The peroneus longus and lateral gastrocnemius were activated significantly earlier, and the anterior tibialis, lateral gastrocnemius, and rectus femoris were activated significantly longer across the stride cycle in the ADB and the ADS conditions. In addition, the peroneus longus was activated significantly longer in the ADB condition when compared with shod. Conclusions: Both ankle-destabilization devices caused an alteration in muscle activity during walking, which may be favorable to an injured patient. Therefore, implementing these devices in rehabilitation programs may be beneficial to improving neuromuscular control. [ABSTRACT FROM AUTHOR]

Context: Muscle activation during aquatic treadmill (ATM) running has not been examined, despite similar investigations for other modes of aquatic locomotion and increased interest in ATM running. Objectives: The objectives of this study were to compare normalized (percentage of maximal voluntary contraction; %MVC), absolute duration (aDUR), and total (tACT) lower-extremity muscle activity during land treadmill (TM) and ATM running at the same speeds. Design: Exploratory, quasi-experimental, crossover design. Setting: Athletic training facility. Participants: 12 healthy recreational runners (age = 25.8 ± 5 y, height = 178.4 ± 8.2 cm, mass = 71.5 ± 11.5 kg, running experience = 8.2 ± 5.3 y) volunteered for participation. Intervention: All participants performed TM and ATM running at 174.4, 201.2, and 228.0 m/min while surface electromyographic data were collected from the vastus medialis, rectus femoris, gastrocnemius, tibialis anterior, and biceps femoris. Main Outcome Measures: For each muscle, a 2 × 3 repeated-measures ANOVA was used to analyze the main effects and environment-speed interaction (P ≤ .05) of each dependent variable: %MVC, aDUR, and tACT. Results: Compared with TM, ATM elicited significantly reduced %MVC (–44.0%) but increased aDUR (+213.1%) and tACT (+41.9%) in the vastus medialis, increased %MVC (+48.7%) and aDUR (+128.1%) in the rectus femoris during swing phase, reduced %MVC (–26.9%) and tACT (–40.1%) in the gastrocnemius, increased aDUR (+33.1%) and tACT (+35.7%) in the tibialis anterior, and increased aDUR (+41.3%) and tACT (+29.2%) in the biceps femoris. At faster running speeds, there were significant increases in tibialis anterior %MVC (+8.6–15.2%) and tACT (+12.7–17.0%) and rectus femoris %MVC (12.1–26.6%; swing phase). Conclusion: No significant environment–speed interaction effects suggested that observed muscle-activity differences between ATM and TM were due to environmental variation, ie, buoyancy (presumed to decrease %MVC) and drag forces (presumed to increase aDUR and tACT) in the water. [ABSTRACT FROM AUTHOR]

Clinical Scenario: Injury to the plantar fascia, whether acute or chronic, is common among many populations. A conventional multiple-treatment approach is commonly administered by health care providers, consisting of controlling inflammation, managing pain, and promoting healing. Frequently, the initial treatment for plantar fasciitis is targeted at increasing dorsiflexion range of motion by stretching the gastroc-soleus musculature. It has been theorized that inflexibility of the gastroc-soleus complex can lead to excessive pronation and overcompensation of the plantar fascia at the first metatarsal phalangeal joint, therefore increasing the stress at the medial calcaneal insertion. Therefore, it is deemed that gastrocnemius-soleus stretches are a beneficial treatment in the initial stage of a plantar fasciitis treatment or rehabilitation program. Focused Clinical Question: Is a gastrocnemius-soleus stretching program, as a stand-alone treatment variable, effective in the treatment of plantar fasciitis? [ABSTRACT FROM AUTHOR]

Context: A potential variable that could affect rate of temperature elevation with ultrasound is the pressure (mass) that is applied to the transducer head during application. Added pressure could compress the tissue, affecting density and the transmission of ultrasound energy. Little research has been completed to determine the effects of the amount of pressure applied during therapeutic ultrasound in vivo. Objective: To determine the effects of different applied transducer mass on intramuscular temperature during an ultrasound treatment within the left triceps surae. Design: Crossover clinical trial. Setting: Human performance research laboratory. Participants: Convenience sample of thirteen healthy, college-age students. Interventions: Three separate 3-MHz, 1.0-W/cm2 ultrasound treatments were administered 1.5 cm within the triceps surae. The independent variables were the linear temperature standards (0.5°C, 1.0°C, 1.5°C, and 2.0°C above baseline) and the 3 different applied pressures measured in grams (200 g, 600 g, and 800 g). Main Outcome Measures: A thermocouple probe was used to measure triceps surae temperature, and time to reach the temperature standards was recorded during the ultrasound treatments. A 4 × 3 repeated-measures analysis of variance (RM-ANOVA) was used to analyze the differences for temperature points (0.5°C, 1.0°C, 1.5°C, and 2.0°C) and transducer mass (200 g, 600 g, and 800 g) and with respect to time. Results: The results of the RM-ANOVA showed no temperature-point and transducer-mass interaction (F6,72 = 1.69, P = .137) or main effect for mass (F2,24 = 1.23, P = .309). The time required to raise temperature 2°C was 209.1 ± 68.10 s at 200 g, 181.5 ± 61.50 s at 600 g, and 194.9 ± 75.54 s at 800 g. Conclusions: Under the conditions of this study, the amount of mass applied with the transducer during an ultrasound treatment does not ultimately affect the rate of tissue heating. [ABSTRACT FROM AUTHOR]

Objective: To compare active hamstring stiffness in female subjects with and without a history of low back pain (LBP) after a standardized 20-min aerobic-exercise session. Design: Case control. Setting: Laboratory. Participants: 12 women with a history of recurrent episodes of LBP (age = 22.4 ± 2.1 y, mass = 67.1 ± 11.8 kg, height = 167.9 ± 8 cm) and 12 matched healthy women (age = 21.7 ± 1.7 y, mass = 61.4 ± 8.8 kg, height = 165.6 ± 7.3 cm). LBP subjects reported an average 6.5 ± 4.7 on the Oswestry Disability Index. Interventions: Participants walked at a self-selected speed (minimum 3.0 miles/h) for 20 min. The treadmill incline was raised 1% grade per minute for the first 15 min. During the last 5 min, participants adjusted the incline of the treadmill so they would maintain a moderate level of perceived exertion through the end of the exercise protocol. Main Outcome Measures: During session 1, active hamstring stiffness, hamstring and quadriceps isometric strength, and concurrently collected electromyographic activity were recorded before and immediately after the exercise protocol. For session 2, subjects returned 48-72 h after exercise for repeat measure of active hamstring stiffness. Results: Hamstring active stiffness (Nm/rad) taken immediately postexercise was not significantly different between groups. However, individuals with a history of recurrent LBP episodes presented significantly increased hamstring stiffness 48-72 h postexercise compared with controls. For other outcomes, there was no group difference. Conclusions: Women with a history of recurrent LBP episodes presented greater active hamstring stiffness 48-72 h after aerobic exercise. [ABSTRACT FROM AUTHOR]

Purpose: Persistent quadriceps weakness due to arthrogenic muscle inhibition (AMI) has been reported after anterior cruciate ligament (ACL) reconstruction. Fatiguing exercise has been shown to alter lower extremity muscle function and gait mechanics, which may be related to injury risk. The effects of exercise on lower extremity function in the presence of AMI are not currently understood. The purpose of this study was to compare the effect of 30 min of exercise on quadriceps muscle function and soleus motoneuron-pool excitability in ACL-reconstructed participants and healthy controls. Methods: Twenty-six (13 women, 13 men) healthy and 26 (13 women, 13 men) ACL-reconstructed recreationally active volunteers were recruited for a case-control laboratory study. All participants completed 30 min of continuous exercise including alternating cycles of inclined-treadmill walking and bouts of squats and step-ups. Knee-extension torque, quadriceps central activation ratio (CAR), soleus H:M ratio, and soleus V:M ratio were measured before and after 30 min of exercise. Results: There was a significant group × time interaction for knee-extension torque (P = .002), quadriceps CAR (P = .03), and soleus V:M ratio (P = .03). The effect of exercise was smaller for the ACL-R group than for matched controls for knee-extension torque (ACL-R: %Δ = -4.2 [-8.7, 0.3]; healthy: %%Δ = -14.2 [-18.2, -10.2]), quadriceps CAR (ACL-R: %%Δ = -5.1 [-8.0, -2.1]; healthy: %%Δ = -10.0 [-13.3, -6.7]), and soleus V:M ratio (ACL-R: %%Δ = 37.6 [2.1, 73.0]; healthy: %%Δ = -24.9 [-38.6, -11.3]). Conclusion: Declines in quadriceps and soleus volitional muscle function were of lower magnitude in ACL-R subjects than in healthy matched controls. This response suggests an adaptation experienced by patients with quadriceps AMI that may act to maintain lower extremity function during prolonged exercise. [ABSTRACT FROM AUTHOR]

Context: Limitations in gastrocnemius/soleus flexibility that restrict ankle dorsiflexion during dynamic tasks have been reported in individuals with patellofemoral pain (PFP) and are theorized to play a role in its development. Objective: To determine the effect of restricted ankle-dorsiflexion range of motion (ROM) on lower extremity kinematics and muscle activity (EMG) during a squat. The authors hypothesized that restricted ankle-dorsiflexion ROM would alter knee kinematics and lower extremity EMG during a squat. Design: Cross-sectional. Participants: 30 healthy, recreationally active individuals without a history of lower extremity injury. Interventions: Each participant performed 7 trials of a double-leg squat under 2 conditions: a no-wedge condition (NW) with the foot flat on the floor and a wedge condition (W) with a 12° forefoot angle to simulate reduced plantar-flexor flexibility. Main Outcome Measures: 3-dimensional hip and knee kinematics, medial knee displacement (MKD), and ankle-dorsiflexion angle. EMG of vastus medialis oblique (VMO), vastus lateralis (VL), lateral gastrocnemius (LG), and soleus (SOL). One-way repeated-measures ANOVAs were performed to determine differences between the W and NW conditions. Results: Compared with the NW condition, the wedge produced decreased peak knee flexion (P < .001, effect size [ES] = 0.81) and knee-flexion excursion (P < .001, ES = 0.82) while producing increased peak ankle dorsiflexion (P = .006, ES = 0.31), ankle-dorsiflexion excursion (P < .001, ES = 0.31), peak knee-valgus angle (P = .02, ES = 0.21), and MKD (P < .001, ES = 2.92). During the W condition, VL (P = 0.002, ES = 0.33) and VMO (P = .049, ES = 0.20) activity decreased while soleus activity increased (P = .03, ES = 0.64) compared with the NW condition. No changes were seen in hip kinematics (P > .05). Conclusions: Altering ankle-dorsiflexion starting position during a double-leg squat resulted in increased knee valgus and MKD, as well as decreased quadriceps activation and increased soleus activation. These changes are similar to those seen in people with PFP. [ABSTRACT FROM AUTHOR]

Context: Static stretching is commonly used during the treatment and rehabilitation of orthopedic injuries to increase joint range of motion (ROM) and muscle flexibility. Understanding the physiological adaptations that occur in the neuromuscular system as a result of long-term stretching may provide insight into the mechanisms responsible for changes in flexibility. Objective: To examine possible neurological origins and adaptations in the Ia-reflex pathway that allow for increases in flexibility in ankle ROM, by evaluating the reduction in the synaptic transmission of Ia afferents to the motoneuron pool. Design: Repeated-measures, case-controlled study. Setting: Sports medicine research laboratory. Participants: 40 healthy volunteers with no history of cognitive impairment, neurological impairment, or lower extremity surgery or injury within the previous 12 mo. Intervention: Presynaptic and postsynaptic mechanisms were evaluated with a chronic stretching protocol. Twenty subjects stretched 5 times a wk for 6 wk. All subjects were measured at baseline, 3 wk, and 6 wk. Main Outcome Measures: Ankle-dorsiflexion ROM, Hmax:Mmax, presynaptic inhibition, and disynaptic reciprocal inhibition. Results: Only ROM had a significant interaction between group and time, whereas the other dependent variables did not show significant differences. The experimental group had significantly improved ROM from baseline to 3 wk (mean 6.2 ± 0.9, P < .001), 3 wk to 6 wk (mean 5.0 ± 0.8, P < .001), and baseline to 6 wk (mean 11.2 ±0.9, P < .001). Conclusions: Ankle dorsiflexion increased by 42.25% after 6 wk of static stretching, but no significant neurological changes resulted at any point of the study, contrasting current literature. Significant neuromuscular origins of adaptation do not exist in the Ia-reflex-pathway components after a long-term stretching program as currently understood. Thus, any increases in flexibility are the result of other factors, potentially mechanical changes or stretch tolerance. [ABSTRACT FROM AUTHOR]

Context: Limited ankle DF (DF) range of motion (ROM) resulting from restricted gastrocnemius and soleus mobility is associated with a variety of lower extremity pathologies. Several techniques are used clinically to measure ankle DF. Objectives: To evaluate the reliability and minimal detectable change of DF ROM measurement, determine whether there is a difference in measured DF between techniques, and quantify the electromyographic (EMG) activity of the soleus and tibialis anterior muscles associated with the techniques. Design: Repeated measures. Setting: Controlled laboratory setting. Participants: 39 healthy subjects, age 22-33. Main Outcome Measures: DF measurements using 5 different techniques including active and passive DF with the knee extended and flexed to 90° and a modified lunge. EMG activity of the soleus and anterior tibialis muscles. Results: Intrarater reliability values (ICC3,1) ranged from .68 to .89. Interrater reliability (ICC2,1) ranged from .55 to .82. ICCs were the greatest with the modified lunge. The minimal detectable change (MDC95) ranged from 6° to 8° among the different techniques. A significant difference in DF ROM was found between all methods. Measurements taken with active DF were greater than the same measures taken passively. The lunge position resulted in greater DF ROM than both active and passive techniques. EMG activity of the soleus was greater with active DF and the lunge than with passive DF. Conclusions: The modified lunge, which demonstrated excellent intrarater and interrater reliability, may best represent maximal DF. Active end-range DF was significantly greater than passive end-range DF when measured at either 0° or 90° knee flexion. Greater active DF was not explained by inhibition of the soleus. Finally, using the modified lunge, a difference between 2 measurements over time of 6° or more suggests that a meaningful change has occurred. [ABSTRACT FROM AUTHOR]

The author comments on the article "Lack of Neuromuscular Origins of Adaptation After a Long-Term Stretching Program," by Bradley T. Hayes and colleagues. The author says that the study which examined the relationship between neurophysiologic changes and a long-term stretching program is clinically relevant. The author is critical of the study's conclusion that changes in dorsiflexion range of motion were not related to neurophysiologic changes in the soleus muscle.

A correction to the article "The Immediate Effects of an Anterior-to-Posterior Talar Mobilization on Neural Excitability, Dorsiflexion Range of Motion, and Dynamic Balance in Patients With Chronic Ankle Instability" that was published in the 2014 issue is presented.

The article offers the author's insights in response to John Hollman's commentary on their study. The author mentions that he and his colleagues performed a priori power analysis using N. Guissard and J. Duchateau's article "Effect of static stretch training on neural and mechanical properties of the human plantarflexor muscles." The author also agrees with Hollman's comments on the study's insufficient ability to detect small changes, and on interpreting effect sizes rather than P values.