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Infectious disease pathogenesis is still a complex field to study. The course of several clinical signs, such as allodynia and pain, may be observed in domestic animals. However, the knowledge of their pathways and correct treatment need controlled experiments, many of them using laboratory animals. Measuring changes in mechanical thresholds of the hind paw and viscera is a useful technique to observe changes in pain perception in rodents. Withdrawal response can be measured first in baseline tests, which creates better control of experimental groups. Subsequent tests can be performed after inducing infection and adding drugs to the protocol. The use of an electronic von Frey apparatus associated with the use of a facial scale to observe pain-like changes allows a simple, precise, and consistent assessment to evaluate allodynia and pain in mice. Thus, experiments using the present methodology for Trypanosoma evansi infection represent a useful method to evaluate allodynia and pain in laboratory-infected animals, which can be applied to the conventional treatment for livestock animals.

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Introduction: Walking while texting can create gait disturbances that may increase fall risk, especially in outdoors environment. To date, no study has quantified the effect of texting on motor behavior using different dynamic tasks in outdoor environments. We aimed to explore the impact of texting on dynamic tasks in indoor and outdoor environments. Methods: Twenty participants (age 38.3 ± 12.5 years, 12 F) had a Delsys inertial sensor fixed on their back and completed walk, turn, sit-to-stand, and stand-to-sit subtasks with and without texting in both indoor and outdoor environments. Results: While there was no difference in texting accuracy (p = 0.3), there was a higher dual-tasking cost in walking time with texting outdoors than indoors (p = 0.008). Discussion: Dual tasking has a greater impact on walking time outdoors compared to an indoor environment. Our findings highlight the importance of patient education concerning dual-tasking and pedestrian safety in clinical settings.

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Smartphone applications are increasingly being used to measure gait due to their portability and cost-effectiveness. Important reliability metrics are not available for most of these devices. The purpose of this article was to evaluate the test-retest reliability and concurrent validity of spatiotemporal gait using the novel Gait Analyzer smartphone application compared to the Tekscan Strideway. Healthy participants (n=23) completed 12 trials of 10-meter walking, at two separate time points, using Gait Analyzer and while walking across the Tekscan Strideway. The results suggest excellent test-retest reliability for the Gait Analyzer and good test-retest reliability for the Tekscan Strideway for both velocity and cadence. At both time points, these devices were moderately to strongly correlated to one another for both velocity and cadence. These data suggest that the Gait Analyzer and Tekscan Strideway are reliable over time and can comparably calculate velocity and cadence.

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BACKGROUND: Recent studies suggest that the prevalence of cardiac involvement in young competitive athletes with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection appears to be low. AIM: This study aimed to determine the prevalence of cardiovascular involvement in young competitive athletes. METHODS: In this single-center retrospective cohort study from one Division I university; we assessed the prevalence of cardiovascular involvement among collegiate athletes who tested positive for SARS-CoV-2 by polymerase chain reaction testing. Data were collected from June 25, 2020, to May 15, 2021. The primary outcome was the prevalence of cardiac involvement based on a comparison of pre- and post-infection electrocardiogram (ECGs). The secondary outcome was to evaluate for any association between ethnicity and the presence or absence of symptoms. RESULTS: Among 99 athletes who tested positive for the SARS-CoV-2 virus (mean age 19.9 years [standard deviation 1.7 years]; 31% female), baseline ECG changes suggestive of cardiovascular involvement post-infection were detected in two athletes (2/99; 2%). There was a statistically significant association between ethnicity and the presence or absence of symptoms, χ 2 (3, n = 99) = 10.61, P = 0.01. CONCLUSIONS: The prevalence of cardiovascular involvement among collegiate athletes following SARS-CoV-2 infection in this cohort is low. Afro-American and Caucasian athletes are more likely to experience symptoms following SARS-CoV-2 infection in comparison to Hispanic and Pacific Islander athletes; however, there is no association between ethnicity and symptom severity. RELEVANCE FOR PATIENTS: These data add to the growing body of the literature and agree with larger cohorts that the risk of cardiac involvement post-infection appears to be low among elite athletic and semi-professional athletic populations.

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BACKGROUND: It is currently unknown what specific neuronal deficits influence postural instability following SRC; however, the modulation of postural control relies heavily on the appropriate integration of sensory information from the visual, vestibular, and somatosensory system. It is possible symptom provocation of vestibular or ocular function is related to unsteady gait patterns during tandem gait. AIM: The purpose of this study was to evaluate the differences in temporal and center of pressure (CoP) metrics during discrete events of instrumented tandem gait (iTG) among those with sport-related concussion (SRC) compared to healthy controls. Secondarily, this study attempted to evaluate the relationship between iTG CoP metrics and the Vestibular/Ocular Motor Screening (VOMS) Exam. MATERIALS AND METHODS: 30 collegiate athletes with SRC and 30 healthy controls completed three single task (ST) iTG trials on an instrumented walkway and the VOMS. All individuals with SRC were assessed within 24-48 h post-injury while all controls were measured during pre-participation physicals. CoP metrics in the anteroposterior (AP) and mediolateral (ML) directions and time to completion were evaluated during the first, turn and second pass of iTG between groups. VOMS score was correlated to the CoP metrics across the discrete events. RESULTS: Athletes with SRC took longer to complete tandem gait (P<0.001) along with the first pass, second pass but not the turn when compared to the control group. SRC had slower velocity in the AP direction during both the first (P<0.001) and second pass (P<0.001) with increased postural sway in the ML direction during the first pass (P=0.014). During the turn, athletes with SRC had postural sway in the ML direction (P=0.008). Finally, VOMS score was weakly negatively related to CoP velocity in the AP direction during first (r=-0.39) and second (r=-0.36) pass while being weakly positively related to postural sway during the turn (r=-0.30). CONCLUSIONS: Athletes with SRC adopted a more conservative walking pattern and the presence of vestibular and/or ocular symptoms influence the ability to perform heel-to-toe walking. RELEVANCE FOR PATIENTS: Individuals with SRC will walk slower during heel-to-toe walking and move more in the ML direction with great movement in the ML direction while en pointe turning. This may increase given the total amount of vestibular or vision symptoms following the SRC.

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CONTEXT: Lower extremity musculoskeletal (LEMSK) injury may be more prevalent among those with a history of sport-related concussion (SRC). OBJECTIVE: To investigate the relationship between baseline postural control metrics and the LEMSK injury incidence in National Collegiate Athletic Association Division I student-athletes with a history of SRC. SETTING: National Collegiate Athletic Association Division I athletes. DESIGN: Cohort study. PATIENTS OR OTHER PARTICIPANTS: Of 84 total athletes (62 males), 42 had been previously diagnosed with an SRC, and 42 were matched controls based on age, sex, height, weight, and sport. MAIN OUTCOME MEASURE(S): During the preseason baseline evaluation, all participants performed 3 trials of eyes-open and eyes-closed upright quiet stance on a force platform. Medical charts were assessed for all the LEMSK injuries that occurred from preseason baseline to 1 year later. Center-of-pressure data in the anteroposterior and mediolateral directions were filtered before we calculated root mean square and mean excursion velocity; the complexity index was calculated from the unfiltered data. Factorial analysis-of-variance models were used to examine differences between groups and across conditions for root mean square; mean excursion velocity, complexity index, and tests of association to examine between-groups LEMSK differences; and logistic regression models to predict LEMSK. RESULTS: Concussion history and injury incidence were related in the SRC group (P = .043). The complexity index of the SRC group was lower with eyes closed (14.08 ± 0.63 versus 15.93 ± 0.52) and eyes open (10.25 ± 0.52 vs 11.80 ± 0.57) in the mediolateral direction than for the control participants (P < .05). Eyes-open root mean square in the mediolateral direction was greater for the SRC group (5.00 ± 0.28 mm) than the control group (4.10 ± 0.22 mm). Logistic regression models significantly predicted LEMSK only in control participants. CONCLUSIONS: These findings may suggest that LEMSK after SRC cannot be predicted from postural-control metrics at baseline.

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OBJECTIVE: The purpose of this study was to evaluate the influence of a posture-cuing shirt on internal rotation velocity of the shoulder during a tennis swing and to determine this influence on shoulder external rotation position. METHODS: Nine healthy competitive college tennis players from a Division III college participated in this study. High-speed motion capture allowed for 3-dimensional analysis of shoulder kinematics during a tennis serve. Two conditions were evaluated while the athletes performed a high-velocity tennis serve: a standard tennis shirt and a posture-cuing shirt. RESULTS: Shoulder internal rotation velocity increased when wearing the posture-cuing shirt. Peak internal rotation velocity increased from 960.61°/s ± 93.24°/s to 1217.96°/s ± 155.01°/s (t = -1.76, P = .058). Internal rotation velocity at the time of impact increased from 765.18°/s ± 95.48°/s to 900.54°/s ± 105.33°/s (t = -1.50, P = .086). Shoulder maximum external rotation did not differ between the 2 conditions, at 172.00° ± 2.92° and 170.89° ± 3.70° (t = 0.325, P = .754). CONCLUSIONS: Wearing a posture-cuing shirt may possibly alter shoulder kinematics during an overhead sport activity such as tennis. Internal rotation velocity seemed to improve while wearing this shirt, although shoulder external rotation position did not change. It is not known if these improvements can influence injury risk.

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The association between self-reported smoking and overuse injury in a cohort of young men (n = 900) and women (n = 597) undergoing 12 weeks of standardized military instruction, after adjustment for physical activity, health history, and incoming fitness tests was examined. The outcome includes all International Classification of Diseases, 9th Revision codes related to injuries resulting from cumulative microtrauma (overuse injuries). The short survey asked about the subject's demographics, smoking habits, prior injuries sustained, physical activity level, self-perceived fitness, and (for women) menstrual history. From the survey, 4 questions established smoking behavior: smoked at least 100 cigarettes in lifetime, age smoked a whole cigarette for the first time, how many cigarettes smoked during the last 30 days, and how many cigarettes smoked per day during the last 30 days. None of the adjusted hazard ratios for the smoking questions were associated with an increased risk of overuse injury for either sex. Furthermore, this study did not find a significant association with respect to smoking and all injuries in either men or women. In conclusion, smoking does not appear to be an independent risk factor for overuse injury in either young men or women during 12 weeks of standardized military instruction.

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OBJECTIVE: The purpose of this study was to evaluate the opinions of experienced cyclists on perceived influence of a posture-cueing shirt with compressive properties on their comfort and recovery. METHODS: Twenty experienced cyclists wore a compressive shirt during rides and as a postride recovery shirt; cyclists rated their perceived experiences during rides and recovery. They completed 2 separate questionnaires specific to riding or recovery; scores ranged from - 3.0 (negative influence) to + 3.0 (positive influence), addressing posture, discomfort, breathing, and recovery. Data analysis included frequencies and t tests to compare groups. RESULTS: Cyclists completed 53 rides, averaging 95.48 km (SD = 31.72 km), wearing the shirt and reported a perceived benefit (mean score = 1.17, SD = 0.25). For their postride recovery perceptions, scores averaged 1.99 (SD = 0.48) for perceived benefits for recovery. No differences in scores were identified between male and female cyclists during rides (t = - 0.28, P > .05); however, female riders perceived greater benefit during recovery (t = - 2.24, P < .05). There were no correlations with scores and cyclist age, experience, or ride distances during rides or recovery (r = 0.02-0.35). CONCLUSION: A posture-cueing, compressive shirt was rated to have a perceived benefit by experienced cyclists for riding posture, postride posture, spine discomfort, and postride recovery. This study did not evaluate physical or physiologic variables to confirm these perceptions.

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This prospective study evaluated the association of self-reported health habits and behaviors in 2,930 Navy recruits with poor training outcomes, defined as graduating late or separating from training. Although 17% of the men and 21% of the women had a poor training outcome, results suggest that some self-reported measures were associated with poor training outcomes. Men who did not run or jog at least 1 month before basic training or had a previous lower limb injury without complete recovery and women reporting the same or less physical activity compared with their same-age counterparts were more likely to have a poor training outcome. An important first step in decreasing poor training outcomes is encouraging incoming recruits to participate in physical activity and taking steps to identify and rehabilitate recruits who are not completely healed from a lower limb musculoskeletal injury before reporting to basic training.

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Weightlifters have commonly believed that changing joint position can alter specific muscle activation. The magnitude of force produced by a muscle is highly dependent upon the length of the muscle. The purpose of this study was to determine the effect of foot positioning on muscle activation of the superficial quadriceps as measured by surface electromyography (sEMG) during a functional squatting movement in healthy adults. Twenty physically active asymptomatic adults (7 females and 13 males) were included in the study while four different foot positions (Neutral, Internally Rotated, Externally Rotated, and Staggered) were assessed. Three quadriceps muscles (Rectus Femoris (RF), Vastus Medialis Oblique (VMO), and Vastus Lateralis Oblique(VLO) were measured. Raw EMG was transformed using a root mean square algorithm. Six one-way repeated measure ANOVAs were conducted to examine the peak and average RMS amplitude for each muscle across each condition, with an alpha level of 0.05 set a priori. Across all foot positions only the Staggered foot position reached statistical significance when compared to all other foot positions for each muscle group. Results suggest that altering the foot position during a partial weight squat has little to no effect on the EMG amplitudes of the quadriceps. However, more research is needed to examine the concentric and eccentric phases of the squatting motion separately with the addition of full weight bearing squats.

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Running on a road for fitness, sport, or recreation poses unique challenges to the runner, one of which is the camber of the surface. Few studies have examined the effects of camber on running, namely, kinematic studies of the knee and ankle. There is currently no information available regarding muscle response to running on a cambered road surface. The purpose of this study was to investigate the effects of a cambered road on lower extremity muscle activity, as measured by electromyography in recreational runners. In addition, this study examined a true outdoor road surface, as opposed to a treadmill surface. The mean muscle activity of the tibialis anterior, lateral gastrocnemius, vastus medialis oblique, biceps femoris, and gluteus medius were studied. Fifteen runners completed multiple running trials on cambered and level surfaces. During the stance phase, mean activities of tibialis anterior, lateral gastrocnemius, and vastus medialis oblique were greater on the gutter side than the crown side. There were no differences in mean muscle activity during the swing phase. The findings of this study suggest that running on a road camber alters the activity of select lower extremity muscles possibly in response to lower extremity compensations to the cambered condition.

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Parents and caregivers faced with the challenges of transferring children with disability are at risk of musculoskeletal injuries and/or emotional stress. The Caregiver Self-Efficacy Scale for Transfers (CSEST) is a 14-item questionnaire that measures self-efficacy for transferring under common conditions. The CSEST yields reliable data and valid inferences; however, its rating scale structure has not been evaluated for utility. The aims of this study were to evaluate the category response structure of the CSEST, test the utility of a revised rating scale structure, and confirm its psychometric properties. The Rasch Measurement Model was used for all analyses. Subjects included 175 adult caregivers recruited from multiple communities. Results confirm that a revised five-category rating scale structure yields reliable data and valid inferences. Given the relationship between self-efficacy and risk of physical and/or emotional stress, measuring parental self-efficacy for transfers is a proactive process in rehabilitation.

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

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This study evaluated the effects of 4 different weekly stretching protocols on the rate of gain and decline in hamstring flexibility over an 8-week period, across sex. Using a randomized single-blind design, 53 healthy subjects aged 18-46 years were assigned to 1 of 4 stretching protocols or a control group. The stretching protocols consisted of either daily or 3 times per week stretching and performed once or twice each day. These protocols differed in terms of frequency and total weekly stretching time. All the subjects stretched their hamstring muscles for 4 weeks and were measured weekly for their hip range of motion (ROM). Stretching ceased the final 4 weeks as the weekly measurements continued. The results revealed no significant differences in the rate of gain or the rate of loss between the different stretching protocols (2-way analysis of variance, F = 2.60, p > 0.05). All the stretching groups gained in hip ROM from pre to week 4 (F = 269.24, p < 0.001). After cessation, the rate of loss was similar for all the 4 stretching groups (F = 102.86, p < 0.001); all the groups retained significant gains at the end of the study (p < 0.001). The control group did not change over time. Those who stretched at least 6 times per week gained more than those who stretched 3 times per week (24 and 16.8%, respectively, F = 5.20, p < 0.05). Subject sex did not influence ROM changes (p > 0.05). Stretching appears to be equally effective, whether performed daily or 3 times per week, provided individuals stretch at least 2 times each day. Moreover, although women are more flexible than men are, there was no sex difference in terms of stretching response.

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The use of knee braces for the treatment of patellofemoral pain syndrome (PFPS) is widely documented, yet the mechanism by which such braces alleviate knee pain remains unclear. This study attempted to clarify this issue by simplifying the brace to the level of only straps. The effectiveness of an infrapatellar strap for PFPS remains controversial, and the use of a suprapatellar strap has not yet been studied. Quadriceps muscle activity and onset timing parameters were measured with surface electromyography (EMG) during a body-weight squat in 19 healthy subjects during 4 different knee-strapping conditions (infra, supra, both, and none). No differences in normalized mean or peak EMG activity in any part of the quadriceps were found. The onset timing of the vastus lateralis (VL) was significantly delayed when using an infrapatellar strap (p < 0.05) or both straps (p < 0.05) and marginally delayed when using a suprapatellar strap (p < 0.10) in comparison with the no-strap (control) condition. No differences in the vastus medialis oblique (VMO) onset timing or VMO-VL onset timing difference were found among the strapping conditions, although an improvement in timing was noted with the suprapatellar condition. The results provide novel evidence that the application of an infrapatellar strap, suprapatellar strap, or both straps improves quadriceps muscle timing imbalances by delaying VL onset. Because the largest delay in VL onset occurred when wearing both straps, the combined application of an infrapatellar and suprapatellar strap may be the most beneficial in managing patellofemoral pain. Knee straps, unlike braces, are cost effective, nonrestrictive, and can be universally fitted to any knee and based on the results deserve further study in the patellofemoral pain population.

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The primary purpose of this study was to evaluate whether frontal plane (FP) plyometrics, which are defined as plyometrics dominated with a lateral component, would produce similar increases in vertical jump height (VJH) compared to sagittal plane (SP) Plyometrics. Thirty-two junior varsity and varsity high-school basketball players participated in 6 weeks of plyometric training. Players participated in either FP or SP plyometrics for the entire study. Vertical jump height was measured on 3 occasions: preintervention (baseline), at week 3 of preparatory training, and at week 6 of training. Descriptive statistics were calculated for VJH. A 2-way analysis of variance (ANOVA) with repeated measures was used to test the difference in mean vertical jump scores using FP and SP training modalities. Results showed a significant effect over time for vertical jump (p < 0.001). Moreover, a significant time by protocol interaction was noted (p < 0.032). A 1-way ANOVA demonstrated that only the SP group demonstrated improvements over time, in VJH, p < 0.05. The FP group did not improve statistically. The data from this study suggest that FP plyometric training did not have a significant effect on VJH and significant improvement in VJH was seen in subjects participating in SP plyometrics thus reinforcing the specificity principle of training. However, coaches should implement both types of plyometrics because both training modalities can improve power and quickness among basketball players.

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BACKGROUND: The influence of superficial precooling on range of motion (ROM) as part of a stretching program has not been extensively studied. It is not clear if the analgesic effect can benefit a stretching program. HYPOTHESES: Superficial precooling will result in greater gains in ROM as part of a stretching program, compared with stretching without a precooling intervention. Superficial precooling will also result in greater retention in ROM gains following cessation of stretching, compared with stretching without a precooling intervention. STUDY DESIGN: Prospective randomized single-blind test-retest design. METHODS: Twenty-nine participants were randomly assigned to 1 of 2 static stretching protocols: a standard protocol (n, 14; age, 24.6 ± 5.4 years) or a precool protocol (n, 15; age, 25.1 ± 7.3 years). These samples allowed for 80% power for statistical significance testing. Both groups performed static hamstring stretching daily for 4 weeks. The precool group applied ice to the hamstring for 10 minutes before stretching. Both groups stretched for 4 weeks and then stopped stretching for the last 4 weeks. Hip ROM measures were obtained each week for 8 weeks. RESULTS: For the standard group, mean hip ROM increased from 71.4° ± 18.5° to 90.6° ± 20.5° and for the precool group, 71.5° ± 22.3° to 91.8° ± 20.9°. For the standard group, mean hip ROM decreased from 90.6° ± 20.5° to 83.9° ± 20.3° and for the precool group, 91.8° ± 20.9 to 85.0° ± 19.4°. There were no differences between groups at any time in the study (P > .05). CONCLUSIONS: Precooling had no beneficial effects on ROM or on retention of ROM. CLINICAL RELEVANCE: Cold application, before stretching, does not provide any benefit to a stretching program.

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Stretching is performed in rehabilitation and sports conditioning programs. It is not known how often during a week stretching needs to be performed to maintain flexibility. Therefore, the purpose of this study was to determine the influence of intermittent stretching (i.e., 2-3 days/week) on hip range of motion (ROM) following a 4-week, daily stretching program. This study used a randomized, single-blind, test-retest design. Healthy adult subjects, age 18 to 50 years, were randomly assigned to 1 of 2 static stretching protocols: (a) standard protocol or (b) intermittent protocol. All subjects stretched their hamstrings daily for the first 4 weeks. The standard group discontinued all stretching after 4 weeks. The intermittent group continued to stretch 2 to 3 days per week for an additional 4 weeks. All subjects were measured for hip ROM weekly for the full 8 weeks. Thirty-two subjects completed the study (standard group = 14; intermittent group = 18, mean age 24.6 years). Mean hip ROM increased (p < 0.05) for both groups from before protocol (PRE) to Week 4 (standard group gain from 71.4 +/- 18.5 degrees to 90.6 +/- 20.5 degrees and intermittent group gain from 68.6 +/- 15.7 degrees to 89.1 +/- 16.8 degrees). During the final 4 weeks, mean hip ROM decreased (p < 0.05) for the standard group from 90.6 +/- 20.5 degrees to 83.9 +/- 20.3 degrees. Mean hip ROM for the intermittent group did not decrease during the final 4 weeks of the study (89.1 +/- 16.8 degrees to 93.2 +/- 14.9 degrees, p > 0.05). Intermittent stretching (i.e., 2 or 3 days/week) is sufficient to maintain ROM gains acquired from a prior static stretching program. Clinicians and trainers may educate their clients of the benefits of intermittent stretching to maintain flexibility.

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