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April 2020

Effect of Aerobic Exercise Training With and Without Blood Flow Restriction on Aerobic Capacity in Healthy Young Adults: A Systematic Review with Meta-Analysis.
Authors:  Formiga  MF, Fay R, Hutchinson S, Locandro N, Ceballos A, Lesh A, Buscheck J, Meanor J, Owens J, Cahalin LP
Exercise training (ET) with blood flow restriction (BFR) is becoming increasingly popular, but the majority of BFR ET studies have evaluated skeletal muscle strength and hypertrophy. The favorable effect of BFR ET on skeletal muscle and the vasculature appears to improve aerobic capacity (AC) although conflicting results have been observed. The purposes of this systematic review with meta- analysis were to examine the effects of aerobic ET with and without BFR on AC and to compare the effect of low-to-moderate aerobic ET with and without BFR to high-intensity aerobic ET with and without BFR on AC. A comprehensive search for studies examining the effects of aerobic ET with and without BFR on AC was performed. Inclusion criteria were: (a) the study was conducted in healthy individuals, (b) there was random allocation of study participants to training and control groups, (c) BFR was the sole intervention difference between the groups.  A total of seven studies (5 low-to-moderate ET and 2 high-intensity ET) were included in the meta-analysis providing data from 121 subjects. There was a significant standardized mean difference (SMD) of 0.38 (95% CI = 0.01, 0.75) in AC between the BFR and non-BFR groups of all seven studies (z = 2.01; p = 0.04). Separate analyses of the five low-to-moderate aerobic ET studies found similar results with aerobic ET with BFR eliciting a significantly greater AC (z = 2.47; p=0.01) than aerobic ET without BFR (SMD of 0.57; 95% CI = 0.12, 1.01). Separate analyses of the two high-intensity aerobic ET studies with and without BFR found no significant difference in AC between the groups (SMD of – 0.01; 95% CI = – 0.67, 0.64).  The authors concluded that aerobic ET with BFR elicits a significantly greater AC than aerobic ET without BFR in healthy young adults. However, low-to-moderate intensity aerobic ET with BFR elicited a greater improvement in AC than aerobic ET without BFR while high-intensity aerobic ET with BFR did not elicit an improvement in AC over high-intensity aerobic ET without BFR. 

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Posterior Shoulder Tightness and Subacromial Impingement Characteristics in Baseball Pitchers: A Blinded, Matched Control Study.
Authors:   Laudner K, Wong  R, Latal J, Meister K

Baseball pitchers frequently develop varying levels of posterior shoulder tightness (PST) and often present with characteristics associated with subacromial impingement. The purpose of this study was to determine if a group of baseball pitchers with excessive PST (bilateral internal rotation ROM difference >18° and bilateral total arc of motion difference >5°) have differences in subacromial joint space, forward scapular posture, or glenohumeral elevation range of motion (ROM) when compared to a control group. Thirty-five asymptomatic professional baseball pitchers with excessive PST were matched with 35 pitchers with acceptable levels of PST. The investigators measured subacromial space using diagnostic ultrasound, glenohumeral elevation ROM using a digital goniometer, and scapular posture using a double square, and were blinded to the group of each participant. Separate t-tests were used to determine significant differences between groups (p<0.05). The excessive PST group presented with significantly less subacromial space (p=.0007) and glenohumeral elevation ROM (p=.03) compared to the acceptable level PST group. The excessive PST group also had significantly more forward scapular posture than the control group (p=.03). The authors concluded that the baseball pitchers with excessive PST had less subacromial space and glenohumeral elevation ROM, as well as more forward scapular posture in their throwing arms compared to pitchers with acceptable levels of PST.Abstract  |  Full Article (Subscribers Only)  |  Purchase Article

Changes in Infraspinatus and Lower Trapezius Activation in Volleyball Players Following Repetitive Serves.

Authors:  Khal KM, Moore SD, Pryor JL, Singh B
Prolonged and repetitive overhead use of the arm, such as during the volleyball serve, has been linked to overuse injuries. The purpose of this study was to examine changes in activation of the infraspinatus and lower trapezius following performance of repetitive jump-float serves. Six asymptomatic female Division I college volleyball players (age = 19.2±1.1 years, height = 182.9±2.5 cm, weight = 82.1±12.2 kg) performed 87 jump-float serves in 13 intervals of seven serves each on an NCAA regulated indoor volleyball court. Electromyography (EMG) electrodes were connected to TeleMyo DTS wireless sensor with the DTS EMG lead sampling at 1000 Hz. Dependent variables included Median Power Frequency (MPF) of the infraspinatus (IF) and lower trapezius (LT), as well as rating of perceived exertion (RPE), perceptual fatigue measured using the Borg scale, and heart rate (HR). Paired t-tests were performed to examine differences in variables between interval 1 (serves 1-3) and interval 13 (serves 85-87). Pearson’s Correlation Coefficients were calculated to examine relationships between the dependent variables across all 13 intervals. IF MPF demonstrated a significant and clinically meaningful decrease from interval 1 to interval 13, indicating muscular fatigue. The decrease in LT MPF from interval 1 to interval 13 was not statistically significant, though it met criteria for clinical meaningfulness and was underpowered. RPE and perceptual fatigue were strongly correlated (r = 0.889. p < 0.01) as were RPE and HR (r = 0.679, p <0.01) and HR and fatigue (r = 0.631, p < 0.01). IF MPF was weakly related to LT MPF (r = 0.227, p < 0.05).  LT MPF was weakly related to RPE (r = 0.352, p < 0.01), perceptual fatigue (r = 0.313, p < 0.01), and HR (r = 0.322, p < 0.01). The authors concluded that repeated overhead jump-float serves, common in volleyball players, required high effort and induced clinically meaningful muscular fatigue that was not perceived by the participant. Significant changes were observed in IF MPF and percent change and effect size suggest that a meaningful change occurred in LT MPF related to jump-float serving.

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Test-Retest Reliability of the Closed Kinetic Chain Upper Extremity Stability Test (CKCUEST) in a Modified Test Position in Division I Collegiate Basketball Players.
Authors:  Hollstadt K, Boland M, Mulligan I
he closed kinetic chain upper extremity stability test (CKCUEST) as originally described may not be appropriate for assessing athletes interchangeably considering body size variations. A modified test position may be warranted to normalize the CKCUEST to body size, in order to reflect an accurate representation of upper limb function. The purpose of this study was to determine test-retest reliability of the CKCUEST in a modified test position in Division I collegiate basketball players. Fifteen subjects (8 male, 7 female) were recruited from Division I basketball teams. Subjects began in a push-up position with their hands located directly under their shoulders. Subjects performed one 15 second trial of the modified CKCUEST initially and a second trial one week later. Test-retest reliability was 0.88 for men’s basketball, 0.79 for women’s basketball, and 0.90 when both teams were combined. Test mean for men’s basketball were 29.5 ± 4.78 touches, and retest mean were 31.88 ± 4.99 touches. Test mean for women’s basketball were 24.86 ±5.52 touches, and retest mean were 26.71 ± 5.41 touches. Test mean for both teams combined were 27.33 ± 5.5 touches, and retest mean were 29.47 ± 5.67 touches. The authors concluded that the CKCUEST in a modified test position is a reliable assessment tool. Results support previous findings and may contribute to injury prevention and return to sport decision-making. 

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Comparison of Cryotherapy Modality Application Over the Anterior Thigh Across Rugby Union Positions; A Crossover Randomized Controlled Trial.
Authors:  Alexander J, Rhodesa D, Birdsall D, Selfec J
In consideration of the diverse physical traits of rugby union and the known interference adipose tissue has on the ability to cool deeper tissues, evidence is required to understand the effect of cryotherapy modalities to provide optimum outcomes post-injury. The purpose of this study was to investigate differences in the cooling ability of three different cryotherapy modalities in a rugby union population in an attempt to describe optimum cooling protocols for the anterior thigh. Twenty-one healthy male rugby union players took part. Skin surface temperature (Tsk) was measured via thermal imaging camera (ThermoVision A40M, Flir Systems, Danderyd, Sweden) alongside Thermal Comfort and Sensation questionnaires following interventions of either Wetted Ice (WI), Crushed Ice (CI) applied in a polythene bag secured by plastic wrap, or CryoCuff® (CC), applied for 20-minutes over the anterior thigh. Participants were grouped by their typical playing position for the sport of rugby union; i.e. forwards and backs. Significant differences (p=<0.05) in Tsk for all modalities compared to baseline and comparing post Tsk between CI and CC (p=0.01) and WI to CC (p=0.01) were displayed. Significantly greater reductions in Tsk noted immediately-post in the ‘forwards’ group (p=≤0.05) compared to the ‘backs’ group for, all modalities (p=≤0.05). Thermal Comfort and Sensation scores demonstrated significant changes baseline compared to post for all modalities (p=<0.05). No significant differences were found when comparing between modalities for Thermal Comfort (p=0.755) or Sensation (p=0.225) for whole group or between positional groups. The authors found that physiological responses to cooling differed across modalities with WI producing the greatest decrease in Tsk. Significant variability in Tsk was also displayed between positional factions. Results uphold the importance of the individualization of local cooling protocols when considering physical traits and characteristics within a rugby union population. Findings provide further understanding of the physiological responses to cooling through Tsk  quantification in specific populations, helping to guide sports medicine practitioners on optimal cooling applications in sport. 

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Is Step Rate Associated with Running Injury Incidence? An Observational Study with 9-Month Follow Up.

Authors:  Szymanek   EB, Miller EM, Weart AN, Morris JB, Goss DL
Several strategies have been proposed to reduce loading of the lower extremity while running including step rate manipulation. It is unclear however, whether step rate influences the incidence of lower extremity injuries. The purpose of this study was to examine the association between step rate and risk of injury in an adult recreational runner population. A total of 381 runners were prospectively followed for an average of nine months. Two-dimensional video was used to assess preferred step rate during a timed two-mile run or a 5K race. Injury surveillance to record sub-clinical injuries (those for which medical treatment was not sought) was performed via semi-monthly email surveys over the course of one year. Injury surveillance for clinical injuries (those for which medical treatment was sought) was performed via a full medical record review using the Armed Forces Health Longitudinal Technology Application. Clinical, sub-clinical and combined clinical and sub-clinical injury incidence were assessed in separate analyses. Injury was operationally defined as seven or more days of reduced activity due to pain. To assess the predictive validity of running step rate, the step rate of participants who did not develop a musculoskeletal injury during the observation period were compared with the running step rate of participants who did develop an injury during the observation period. Out of 381 runners, 16 sustained a clinical overuse injury for which medical treatment was sought. Mean step rate for clinically un-injured runners was 172 steps/min and mean step rate for clinically injured runners was 173 steps/min which was not statistically significantly different (p = 0.77). Out of 381 runners, 95 completed all four sub-clinical injury surveys (95/381 = 25%). Out of those 95 runners, 19 sustained a clinical (n=4) or sub-clinical injury (n=15). The step rate of sub-clinically injured and non-injured runners in this sub-sample was also not statistically significantly different (p = 0.08), with a mean of 174 steps/min for the uninjured group and a mean step rate of 170 steps/min for those in the sub-clinical injured group. The authors concluded that a preferred step rate was not associated with lower extremity injury rates in this sample of DoD runners. Additional research is needed to justify preferred step rate manipulation as a means to reduce lower extremity injury risk. 

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Comparative Analysis of Hip Muscle Activation During Closed-Chain Rehabilitation Exercises in Runners.
Authors:   Connelly CM, Moran MF, Grimes JK
Increased hip adduction and internal rotation during the early stance phase of running have been linked to an increased risk of lower extremity injury. Both the gluteus maximus (GMAX) and gluteus medius (GMED) eccentrically control these motions. GMAX and GMED activation levels during commonly used rehabilitation exercises requires further exploration. The purpose of this study was to compare peak surface electromyography (sEMG) amplitudes of GMAX and GMED between three closed-chain rehabilitation exercises: bilateral hip external rotation with resistance band (BER), forward lunge with resistance band (FL), and single-leg rotational squat (SLS). It was hypothesized that the FL would elicit greater peak amplitude in the GMAX and GMED than SLS and BER. Twenty-two healthy runners (14 male, 8 female) had sEMG electrodes placed bilaterally on GMAX and GMED. Participants completed three repetitions each of BER, FL, and SLS exercises with sEMG data normalized to the maximal amplitude recorded at each muscle during the running trial (% MRC). Seven inertial measurement units affixed to the lower extremity measured joint kinematics to enable the exercises to be split into eccentric and concentric phases. There were no significant differences between exercises during the eccentric phases with all peak amplitudes for GMAX and GMED being less than < 30% MRC. Both the SLS (GMAX: 48.2 ± 45.2% MRC, p = 0.019; GMED: 39.3 ± 24.8% MRC, p <.001) and FL (GMAX: 65.8 ± 58.9% MRC, p <.001; GMED: 52.2 ± 34.9% MRC, p<.001) elicited significantly greater peak amplitudes than BER (GMAX: 21.7 ± 22.3% MRC; GMED: 22.8 ± 21.2% MRC) during the concentric phase. Running related injuries have been linked to deficits in GMAX and GMED activation and strength. When averaged bilaterally across 22 healthy runners, peak GMAX and GMED amplitudes during three weight bearing exercises were less than 70% MRC. All three exercises had comparable eccentric peak amplitudes; however, the BER exercise produced a significantly reduced GMAX and GMED amplitude during the concentric phase versus the FL and SLS. The FL and SLS appear equally effective at eliciting peak GMAX and GMED activation.

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Reliability and Validity of The Hip Abductor Isometric Endurance Test: A New Method to Assess the Endurance of the Hip Abductors.

Authors:  VanCant J, Detrembleur C, Mahaudens P, Feipel V
Substantial deficits in the performance of the hip abductor muscles are reported in females with common lower extremity conditions. In this context, the hip abductor isometric test (HAIE) test has been developed to assess the endurance of the hip abductors. The aims of the study were: 1) to assess the test-retest reliability of the HAIE test and 2) to determine if the HAIE test is valid for the measuring hip abductor muscle fatigue. Fifty-two healthy females, aged 18-30 years, were recruited. In two identical sessions, spaced by seven days, the participants performed the HAIE test and the test-retest reliability (ICC, SEM and MDC) was calculated. In ten subjects, surface EMG was used during the test in order to observe the change in the median frequency of EMG output of the gluteus medius and to determine if decrease of the median frequency is correlated with performance on the test, in order to discern validity. The HAIE test demonstrated good test-retest reliability (ICC = 0.84, SEM = 11.5 seconds and MDC = 32.8 seconds). Significant differences were noted between the average median frequency of participants for the last four fifteen second intervals (p= 0.02). Moderate correlation between MFslope and endurance time (r = 0.56, p = 0.008) and strong correlation between MFslope75s and endurance time (r = 0.71, p = 0.001) were found.   The results from this study support that the HAIE test is a reliable test for evaluating the endurance of the hip abductors. Further investigations should continue to explore the validity of the test, especially to determine which muscles limit the endurance time in healthy and unhealthy subjects.Abstract  |  Full Article (Subscribers Only)  |  Purchase Article

Eccentric Hamstring Strength is Associated with Age and Duration of Previous Season Hamstring Injury in Male Soccer Players.

Authors:  Vicens-Bordas J, Esteve E, Fort-Vanmeerhaeghe A, Clausen MB, Bandholm T, Opar D, Shield A, Thorborg K
Eccentric hamstring strength seems important in reducing the odds of future hamstring injuries. While age and previous injury are well-known risk factors for future hamstring injuries, the association of age and previous hamstring injury with eccentric hamstring strength in the following season is unknown. The purpose of this study was to investigate the association of age and previous hamstring injury with preseason eccentric hamstring strength in soccer players, and to investigate the association between previous hamstring injury duration and preseason eccentric hamstring strength. A convenience sample of 284 male amateur soccer players (age 18-38 years) was included in the analyses. Self-reported information about previous season hamstring injury and its duration (three weeks or less; more than three weeks) was collected. Preseason eccentric hamstring strength was obtained during the Nordic hamstring exercise using a field-based device. Age had a negative association with preseason eccentric hamstring strength with 0.9% reduction per year. Players with a previous hamstring injury duration of more than three weeks (n=27) had 13% lower preseason eccentric hamstring strength compared to players without previous hamstring injury.  The authors concluded that older players have lower preseason eccentric hamstring strength than younger players. Players with a previous hamstring injury duration of more than three weeks have lower preseason eccentric hamstring strength than the rest of the players. These results highlight the need to monitor and address the identified weaknesses in eccentric hamstring strength in amateur soccer players, with specific emphasis on older players with a previous hamstring injury of longer duration.Abstract  |  Full Article (Subscribers Only)  |  Purchase Article

Analysis of Timing of Secondary ACL Injury in Professional Athletes Does Not Support Game Timing or Season Timing as A Contributor To Injury Risk.

Authors:  Zhou J,  Schilaty ND, Hewett TE, Bates NA
Anterior cruciate ligament (ACL) injuries are a common cause of time loss in sports. Approximately one-third of ACL reconstructed athletes who return to sport suffer secondary injury. The presence of fatigue during athletic performance has been hypothesized to increase susceptibility to ACL injury. However, the relative role of fatigue in secondary ACL failures remains unexplored. The purpose of this study was to assess how time elapsed within a game and within a season associate with secondary ACL injury occurrence in international professional athletes and American collegiate athletes. The public domain was searched for secondary ACL injuries that occurred during competitive matches between 2000-2018. Demographics (age, height, weight), side of injury, type of injury (contact, noncontact), and timing of injury within competition and within season were determined for each case. Sixty-seven secondary ACL injuries were identified. Within-game, there were no differences in the distribution of ACL injures across each quarter of game time (p = 0.284). This was consistent between sport (p = 0.120-0.448). Within-season, there were no differences in the distribution of secondary ACL injures across each quarter of the season (p = 0.491). This was again consistent between sport (p = 0.151-0.872). Relative risk was not found to be significantly greater for any combination of season and game. The results of the current study indicate that the occurrences of secondary ACL injuries were equally distributed with respect to in-game and in-season timing. Both in-game and in-season timing were not significantly different across each individual sport examined. These results indicate that overall  there is not an association between fatigue and secondary ACL injury occurrence in professional athletes.

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An Exploratory Case Series Analysis of the Use of Primal Reflex Release Technique™ to Improve Signs and Symptoms of Hamstring Strain.

Authors:  Albertin ES, Walters M, May J, Baker RT, Nasypany A, Cheatham S
Hamstring strain (HS), a common condition found among the injured physically active population, is often treated with rest, stretching, and modalities. Primal Reflex Release Technique™ (PRRT™) is a manual therapy technique used to treat pain caused by over-stimulation of the body’s primal reflexes. The purpose of this case series was to explore the immediate effects of PRRT™ for treating hamstring strains. In this case series, the use of PRRT™ resulted in decreased pain, increased function, and increased range of motion, as well as resolved SJD. The Primal Reflex Release Technique™ may be useful in decreasing symptoms of HS acutely, but long-term effects are unknown at this time. Clinicians should consider using a treatment which targets the autonomic nervous system when addressing pain associated with HS.

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The Management of Plantar Fasciitis with a Musculoskeletal Ultrasound Imaging Guided Approach for Instrument Assisted Soft Tissue Mobilization in a Runner: A Case Report.

Authors:  Sillevis R, Shamus E, Mouttet B
Musculoskeletal ultrasound imaging (MSK US) is an emerging diagnostic tool in physical therapy, which allows for dynamic visualization of tissues in real time. Plantar fasciitis is a common condition causing heel and arch pain and has been related with degenerative changes in the plantar fascia resulting in tissue thickening. Instrument Assisted Soft Tissue Mobilization (IASTM) is an intervention that allows clinicians deep penetration to treat tissues. The mechanical forces caused by IASTM might cause localized tissue trauma leading to stimulation of the body’s natural inflammation and healing processes. The purpose of this case report is to demonstrate the use of ultrasound imaging to guide the decision-making process and to discern the optimal location for the application of IASTM.  MSK US was used to determine the optimal location for the application of IASTM during the conservative management of a runner with plantar fasciitis.

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Rehabilitation Considerations for Spondylolysis in the Youth Athlete.

Authors:  Selhorst M,  Allen M, McHugh R, MacDonald J
Low back pain in adolescent athletes is quite common, and an isthmic spondylolysis is the most common identifiable cause.  Spondylolysis, a bone stress injury of the pars interarticularis, typically presents as focal low back pain which worsens with activity, particularly with back extension movements. Research on spondylolysis has focused on diagnosis, radiographic healing, the effects of bracing and rest from activity.  Although physical therapy is frequently recommended for adolescent athletes with spondylolysis, there have been no randomized controlled trials investigating rehabilitation. Additionally, there are no detailed descriptions of physical therapy care for adolescent athletes with spondylolysis. The purpose of this clinical commentary is to provide a brief background regarding the pathology of isthmic spondylolysis and provide a detailed description of a proposed plan for physical therapy management of spondylolysis in adolescent athletes.

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Past, Current and Future Interventional Orthobiologics Techniques and How They Relate to
Regenerative Rehabilitation: A Clinical Commentary.

Authors:  Centeno CJ, Pastoriza SM
Interventional orthobiologics is changing the landscape of orthopedic medicine. Various methods exist for treatment of many different musculoskeletal pathologies. Candidacy for such injections remains a debated topic, and current research is underway for stratifying the patients that would be most successful for certain techniques. Described in this commentary are the various methods of interventional orthobiologic techniques available such as: prolotherapy, platelet rich plasma (PRP), mesenchymal stromal cells (MSCs), culture-expanded MSCs and amniotic-based products. Here we review the healing cascade and how this relates to the application of the various injectates and rehabilitation protocols. Orthobiologic techniques exist to assist in the healing of a multitude of musculoskeletal ailments, from ligamentous instabilities/tears, tendon derangements and osteoarthritis, however discussions continue as to which type of treatment is the most beneficial, and which rehabilitation protocols are required. More randomized controlled trials and comparative analyses are needed for direct correlative conclusions regarding which interventional orthobiologic treatment and rehabilitation protocols are best after each respective treatment.

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Criteria-Based Return to Sprinting Progression Following Lower Extremity Injury.

Authors:  Lorenz D,  Domzalski S
In the terminal phases of athletic rehabilitation, transitioning back to sport is a critical aspect to prepare an athlete for return to full participation. Numerous interval return to sport programs and return to sports guidelines as well as criteria-based progressions for returning to sport have been published, but no such protocol exists for returning to the task of sprinting. Any field or court athlete must be able to sprint as part of his/her sport demands. Because of the absence of a specific progression, sports rehabilitation professionals lack knowledge about objective criteria to progress to sprinting as well as a progressive program to do so.  Given that sports rehabilitation professionals have limited visits to complete rehabilitation or their athletes have limited financial resources to do so, it is imperative that a structured, criteria-based progression be available. The purpose of this clinical suggestion is to provide a criteria-based return to sprinting progression.

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