Acute Hamstring Strain Research Articles

Relationships between quantitative magnetic resonance imaging measures at the time of return to sport and clinical outcomes following acute hamstring strain injury

Hamstring strain injuries (HSI) are a common occurrence in athletics and complicated by high rates of reinjury. Evidence of remaining injury observed on magnetic resonance imaging (MRI) at the time of return to sport (RTS) may be associated with strength deficits and prognostic for reinjury, however, conventional imaging has failed to establish a relationship. Quantitative measure of muscle microstructure using diffusion tensor imaging (DTI) may hold potential for assessing a possible association between injury-related structural changes and clinical outcomes. The purpose of this study was to determine the association of RTS MRI-based quantitative measures, such as edema volume, muscle volume, and DTI metrics, with clinical outcomes (i.e., strength and reinjury) following HSI. Spearman’s correlations and Firth logistic regressions were used to determine relationships in between-limb imaging measures and between-limb eccentric strength and reinjury status, respectively. Twenty injuries were observed, with four reinjuries. At the time of RTS, between-limb differences in eccentric hamstring strength were significantly associated with principal effective diffusivity eigenvalue λ1 (r = -0.64, p = 0.003) and marginally associated with mean diffusivity (r = -0.46, p = 0.056). Significant relationships between other MRI-based measures of morphology and eccentric strength were not detected, as well as between any MRI-based measure and reinjury status. In conclusion, this preliminary evidence indicates DTI may track differences in hamstring muscle microstructure, not captured by conventional imaging at the whole muscle level, that relate to eccentric strength.

Limited Return to Preinjury Performance in NCAA Division I American Football Players With Hamstring Injuries.

Hamstring strains are common among elite athletes, but their effect on return to the same level of play in American football has been incompletely characterized. Data on National Collegiate Athletics Association Division I college football players with acute hamstring strains were gathered to identify the effects these injuries have on both return to play and athletic performance regarding velocity, workload, and acceleration. Case Series; Level of evidence, 4. Injury data for a single Division I football team were prospectively recorded over a 4-year period. Players wore global navigation satellite system and local positioning system (GNSS/LPS) devices to record movement data in practices and games. The practice and game data were cross-referenced to evaluate players with isolated acute hamstring strains. Comparisons were made regarding players' pre- and postinjury ability to maintain high velocity (>12 mph [19.3 kph]), maximal velocity, triaxial acceleration, and inertial movement analysis (IMA). There were 58 hamstring injuries in 44 players, of which 25 injuries from 20 players had GNSS/LPS data. Players were able to return to play from all 25 injury incidences at a mean of 9.2 days. At the final mean follow-up of 425 days, only 4 players had reached preinjury function in all measurements; 12 players were able to return in 2 of the 4 metrics; and only 8 players reached their preinjury ability to maintain high velocity. For those who did not achieve this metric, there was a significant difference between pre- and postinjury values (722 vs 442 m; P = .016). A total of 14 players were able to regain their IMA. Players who returned to prior velocity or acceleration metrics did so at a mean of 163 days across all metrics. While players may be able to return to play after hamstring strain, many players do not reach preinjury levels of acceleration or velocity, even after 13.5 months. Further studies are needed to confirm these findings, assess clinical relevance on imaging performance, and improve hamstring injury prevention and rehabilitation.

Hamstring Strain Ultrasound Case Series: Dominant Semitendinosus Injuries in National Collegiate Athletic Association Division I Athletes.

Authors of previous studies of patients with acute hamstring strains have reported injury to the biceps femoris and semitendinosus (ST) in 50% to 100% and 0% to 30%, respectively. This retrospective case series of hamstring injuries in National Collegiate Athletic Association Division I collegiate athletes exhibited an injury pattern on ultrasound imaging that differed from what would be expected based on prior literature. We examined ultrasound images of 38 athletes with acute hamstring strains for injury location (proximal muscle, proximal myotendinous junction, midportion of muscle, distal muscle) and affected muscles (biceps femoris, ST, or semimembranosus). Twenty-six athletes (68.4%) injured the ST, and 9 athletes (23.7%) injured the biceps femoris long head. Most athletes (23, 60.5%) injured the proximal portion of the muscle or myotendinous junction. Though this study had many limitations, we demonstrated more frequent involvement of the ST and less frequent involvement of the biceps femoris than reported in the literature.

Association of quantitative diffusion tensor imaging measures with time to return to sport and reinjury incidence following acute hamstring strain injury

Hamstring strain injuries (HSI) are a common occurrence in athletics and complicated by limited prognostic indicators and high rates of reinjury. Assessment of injury characteristics at the time of injury (TOI) may be used to manage athlete expectations for time to return to sport (RTS) and mitigate reinjury risk. Magnetic resonance imaging (MRI) is routinely used in soft tissue injury management, but its prognostic value for HSI is widely debated. Recent advancements in musculoskeletal MRI, such as diffusion tensor imaging (DTI), have allowed for quantitative measures of muscle microstructure assessment. The purpose of this study was to determine the association of TOI MRI-based measures, including the British Athletic Muscle Injury Classification (BAMIC) system, edema volume, and DTI metrics, with time to RTS and reinjury incidence. Negative binomial regressions and generalized estimating equations were used to determine relationships between imaging measures and time to RTS and reinjury, respectively. Twenty-six index injuries were observed, with five recorded reinjuries. A significant association was not detected between BAMIC score and edema volume at TOI with days to RTS (p-values ≥ 0.15) or reinjury (p-values ≥ 0.13). Similarly, a significant association between DTI metrics and days to RTS was not detected (p-values ≥ 0.11). Although diffusivity metrics are expected to increase following injury, decreased values were observed in those who reinjured (mean diffusivity, p = 0.016; radial diffusivity, p = 0.02; principal effective diffusivity eigenvalues, p-values = 0.007–0.057). Additional work to further understand the directional relationship observed between DTI metrics and reinjury status and the influence of external factors is warranted.

Associations of time to return to performance following acute posterior thigh injuries with running biomechanics, hamstring function, and structure in collegiate sprinters: A prospective cohort design.

The time to return to sport from acute hamstring strain injuries is associated with several functional and structural impairments. However, not all previous studies assessed the preinjury level before acute hamstring strain injuries directly. The purpose of this study was to examine the associations of the time to return to performance following acute hamstring strain injuries with deficits in running biomechanics, hamstring function and structure in collegiate sprinters by a prospective study. Using a prospective cohort design, 72 participants were recruited from a collegiate track and field team. At the preinjury assessment, a 60-m running-specific test, passive straight leg raise test and isometric knee flexion strength test were assessed at the beginning of the competitive season for three consecutive years (2017-2019). Afterwards, postinjury examinations were performed only in sprinters with acute hamstring strain injuries. Twelve sprinters strained their hamstring muscle (incidence rate of hamstring strain injuries: 16.7%); the majority (n=10) were classified as grades 0-2. The running speed deficit of the running-specific test was associated with the time to return to performance as well as the passive straight leg raise test deficit. In the running-specific test, lower-limb kinetic deficits were more strongly associated with the time to return to performance compared to lower-limb kinematic deficits. A running-specific test may be considered one of the most convenient and valid tests for assessing rehabilitation progress after acute hamstring strain injuries.

Hamstring Injuries: Critical Analysis Review of Current Nonoperative Treatments

Hamstring injuries are common among active and athletic individuals, especially those involved in high-speed running, distance running, or sports requiring sudden directional changes. Acute hamstring strains often occur as an eccentric strain during running or a stretch-type injury caused by simultaneous hip flexion and knee extension. Proximal hamstring tendinopathy is an overuse injury of the hamstring tendon as a result of chronic cicatrization of the musculotendinous unit. Repeated stress to the hamstring tendon leads to increased cellularity of tendon fibers, disruption of collagen, and subsequent microinjury of the tissue that attaches the tendon to bone. Management of hamstring injuries generally begins with nonoperative modalities consisting of eccentric rehabilitative exercise programs. Although various other treatment modalities are available, the comparative efficacy of these supportive measures is not well differentiated at this time. In this article, we review the current literature with regard to the nonoperative treatment of hamstring injuries, specifically focusing on acute hamstring muscle strains and proximal hamstring tendinopathy in order to provide supplementary insight on the effectiveness of current modalities.

Its not all about sprinting: mechanisms of acute hamstring strain injuries in professional male rugby union—a systematic visual video analysis

ObjectivesThe mechanisms of hamstring strain injuries (HSIs) in professional Rugby Union are not well understood. The aim of this study was to describe the mechanisms of HSIs in male professional...

Effects of Sex and Age on Quadriceps and Hamstring Strength and Flexibility in High School Basketball Athletes.

BackgroundEccentric hamstring strength and hamstring/quadriceps strength ratios have been identified as modifiable risk factors of hamstring strains. Additionally, those strength and flexibility characteristics are commonly used as clinical tests to monitor progress of athletes with acute or chronic hamstring strains. Although hamstring strains are common among basketball athletes, normative values of knee strength and flexibility characteristics are scarce. Normative values for these athletes would be important in prevention and management of hamstring strains.PurposeTo establish quadriceps and hamstring isokinetic strength and flexibility values among high school basketball athletes and examine the effects of sex and age.Study DesignCross-sectional researchMethodsIsokinetic knee muscular strength (concentric quadriceps [QuadC], concentric hamstring [HamC], eccentric hamstring [HamE], and strength ratios ([HamC/QuadC and HamE/Quad]), flexibility of hip flexors and quadriceps during a Modified Thomas test, and flexibility of hip extensors and hamstring during passive straight leg raise (SLR) and passive knee extension (PKE) tests were measured. Effects of sex and age were analyzed using t-tests and analysis of variance, respectively with Bonferroni corrected post hoc tests (p≤0.01).ResultsA total of 172 high school basketball athletes (64 males/108 females; mean age (range): 15.7 (14-18) years old) participated in the study. Male athletes were significantly stronger than female athletes (QuadC: p<0.001; HamC: p<0.001) while no differences were observed in strength ratio (HamC/QuadC: p=0.759-0.816; HamE/QuadC: p=0.022-0.061). Among male athletes, a significant effect of age on quadriceps and hamstring strength was observed: older male athletes were stronger than younger male athletes. Contrarily, there were no effects of age on strength among female athletes. There were significant sex differences in quadriceps flexibility, SLR, and PKE (female athletes were more flexible; p=0.001-0.005) while no sex differences were found in hip flexor flexibility (p=0.105-0.164). There were no effects of age for any flexibility variables within male and female athletes (p=0.151-0.984).ConclusionThe current results provide normative values for hamstring strength and flexibility in high school basketball athletes. These normative values may further assist sports medicine specialists to develop screening tests, interventions, and return-to-sport criteria in this population.Level of Evidence3B

Between-limb Differences In Hamstrings Activation Not Observed During Sprinting After Acute Hamstring Strain Injury

Between-limb Differences In Hamstrings Activation Not Observed During Sprinting After Acute Hamstring Strain Injury

Between-limb Differences In Ultrasound Spatial Frequency Analysis Parameters Following Acute Hamstring Strain Injury

Treatment following hamstring strain injury (HSI) is complicated by a lack of prognostic indicators and high rates of re-injury. Spatial frequency (SF) analysis, a quantitative ultrasound method to assess structural tissue organization, could complement clinical evaluations. PURPOSE: To characterize differences in SF parameters between injured and uninjured limbs following acute HSI in Division I collegiate athletes. METHODS: Ultrasound imaging was performed within one week of HSI, also confirmed by MRI. Longitudinal B-mode images (Aixplorer, Supersonic Imagine, Aix-en-Provence, France) were acquired by a single musculoskeletal-trained sonographer using a linear array transducer (2-10 MHz) at the injury site of maximum tenderness and corresponding location for the uninjured limb. A region of interest (ROI) was drawn about the site of injury and location-matched on the images of the uninjured limb. A 2D Fourier Transform was performed on all possible 5 mm square kernels within the ROI. Peak spatial frequency radius (PSFR), a parameter corresponding to the frequency of the fascicular banding pattern, and Mmax%, a ratio comparing the prominent banded pattern relative to the background, were computed for each kernel. PSFR and Mmax% from all kernels were averaged across respective ROIs. Paired t-tests were used to compare parameter differences between limbs. RESULTS: Seven male athletes sustained HSI (mean age = 19.1 ± 0.8 yrs). PSFR (1/mm) was lower (p = 0.005) in the injured limb (0.81 ± 0.22) compared to the uninjured limb (0.95 ± 0.18). Mmax% was also lower (p = 0.023) in the injured limb (1.44 ± 0.41) compared to the uninjured limb (2.03 ± 0.56). Both measures indicated decreased tissue organization in the injured limb, characterized by disruption of the reflected fascicular banded pattern. CONCLUSION: SF analysis successfully detected differences between injured and uninjured muscle tissue. Although differences in SF parameters between limbs cannot differentiate whether alterations are due to mechanical disruption of fascicles or presence of edema, this method may have promise in identifying structural changes following HSI and in monitoring changes throughout recovery.Supported by NBA & GE Healthcare Orthopedics and Sports Medicine Collaboration and NIH Grant UL1TR002373 and TL1TR002375.

Mechanisms of Hamstring Strain Injury: Interactions between Fatigue, Muscle Activation and Function

Isolated injury to the long head of biceps femoris is the most common type of acute hamstring strain injury (HSI). However, the precise hamstring injury mechanism (i.e., sprint-type) is still not well understood, and research is inconclusive as to which phase in the running cycle HSI risk is the greatest. Since detailed information relating to hamstring muscle function during sprint running cannot be obtained in vivo in humans, the findings of studies investigating HSI mechanisms are based on modeling that requires assumptions to be made based on extrapolations from anatomical and biomechanical investigations. As it is extremely difficult to account for all aspects of muscle-tendon tissues that influence function during high-intensity running actions, much of this complexity is not included in these models. Furthermore, the majority of analyses do not consider the influence of prior activity or muscular fatigue on kinematics, kinetics and muscle activation during sprinting. Yet, it has been shown that fatigue can lead to alterations in neuromuscular coordination patterns that could potentially increase injury risk. The present critical review will evaluate the current evidence on hamstring injury mechanism(s) during high-intensity running and discuss the interactions between fatigue and hamstring muscle activation and function.

MAPPING TENDERNESS TO PALPATION PREDICTS RETURN TO PLAY FOLLOWING ACUTE HAMSTRING STRAIN

Currently there is little evidence supporting the use of objective tests, measures, or imaging to help predict time to return to sport (RTS) following a hamstring strain. The purpose of this study is to investigate the predictive value of tenderness to palpation (TTP) as measured by area and location following hamstring strain. Case Series. Nineteen male athletes (age 28 ± 9 yr) who sustained an acute hamstring strain underwent hamstring tenderness mapping on initial evaluation. The length and width of tenderness of the hamstring was identified with manual palpation, outlined in pen, and was then calculated as a percentage of the length and width of the posterior thigh. All patients underwent the same hamstring rehabilitation protocol with remapping performed at specific stages in rehabilitation. The association between mapping tenderness indices and RTS was assessed by linear regression. The average length of the area of tenderness was 22 ± 12% with an average RTS of 43 ± 36 days. The length of the area of tenderness measured on initial evaluation was a strong predictor of RTS (R2 = 0.58, p<0.001; y = 2.3x - 6.2). Area of injury (R2 = 0.36, p = 0.006) and age (R2 = 0.27, p = 0.024) were also related to RTS, while width of injury (R2 = 0.006, p = 0.75) and location of injury were not (proximal-distal p = 0.62, medial-lateral p = 0.64). Adding age with length of injury into a multiple regression analysis improved the prediction of RTS (R2 = 0.73). The relationship between RTS and length of tenderness was relatively unchanged when the additional mapping indices taken during the course of rehabilitation were added to the analysis (R2 = 0.61, p<0.001; y = 2.3x - 4.4). This indicates that the regression equation can be used to estimate RTS regardless of when in the post injury/rehabilitation process the mapping is performed. The length of the area of tenderness to palpation of the injured hamstring muscle was highly predictive of RTS time. Based on the regression equation a patient with a length of tenderness of 10% would have an estimated RTS time of 17 days, while a tenderness length of 30% would be estimated to return in 63 days. This hamstring mapping technique described was predictive of the RTS and may be a useful clinical tool. IIb.

What is the most effective treatment of acute proximal hamstring strain to improve recovery time?

What is the most effective treatment of acute proximal hamstring strain to improve recovery time?

Pain-Free Versus Pain-Threshold Rehabilitation Following Acute Hamstring Strain Injury: A Randomized Controlled Trial.

The primary aim was to compare time from acute hamstring strain injury (HSI) to return-to-play (RTP) clearance following a standardized rehabilitation protocol performed within either pain-free or pain-threshold limits. Secondary aims were to compare isometric knee flexor strength, biceps femoris long head (BFLH) fascicle length, fear of movement, and reinjury occurrence at the 6-month follow-up between pain-free and pain-threshold groups. Randomized controlled trial. Forty-three men with acute HSIs were randomly allocated to a pain-free (n = 22) or pain-threshold (n = 21) rehabilitation group. Days from HSI to RTP clearance, isometric knee flexor strength, BFLH fascicle length, fear of movement, and reinjury occurrence at the 6-month follow-up were reported. Median time from HSI to RTP clearance was 15 days (95% confidence interval [CI]: 13, 17) in the pain-free group and 17 days (95% CI: 11, 24) in the pain-threshold group, which was not significantly different (P = .37). Isometric knee flexor strength recovery at 90° of hip and 90° of knee flexion was greater in the pain-threshold group at RTP clearance by 15% (95% CI: 1%, 28%) and by 15% (95% CI: 1%, 29%) at 2-month follow-up, respectively. Improvement in BFLH fascicle length from baseline was 0.91 cm (95% CI: 0.34, 1.48) greater at 2-month follow-up in the pain-threshold group. Two reinjuries occurred in both the pain-free and pain-threshold groups between RTP clearance and the 6-month follow-up. Pain-threshold rehabilitation did not accelerate RTP clearance, but resulted in greater recovery of isometric knee flexor strength and better maintenance of BFLH fascicle length, compared to pain-free rehabilitation. J Orthop Sports Phys Ther 2020;50(2):91-103. Epub 28 Jun 2019. doi:10.2519/jospt.2020.8895.

Pain-Free Versus Pain-Threshold Rehabilitation Following Acute Hamstring Strain Injury: A Randomized Controlled Trial.

Randomized controlled trial. Conventional guidelines recommend hamstring strain injury (HSI) rehabilitation should only be performed and progressed in complete absence of pain, despite lack of comparison to alternative approaches. The primary aim of this study was to compare the number of days from acute HSI to return to play (RTP) clearance following a standardised rehabilitation protocol performed within either pain-free or pain-threshold limits. The secondary aims were to compare isometric knee flexor strength, biceps femoris long head (BFlh) fascicle length, fear of movement and re-injury during a six-month follow-up between pain-free and pain-threshold groups. Forty-three men with acute HSIs were randomly allocated to either a pain-free (n=22) or pain-threshold (n=21) rehabilitation group. Days from HSI to RTP clearance, isometric knee flexor strength, BFlh fascicle length, fear of movement and re-injuries within six-month follow-up were reported. The median time from HSI to RTP clearance was 15 days (95% CI = 13 to 17) in the pain-free group and 17 days (95% CI = 11 to 24) in the pain-threshold group, which was not significantly different (p = 0.37). Recovery of isometric knee flexor strength at 90/90 degrees of hip/knee flexion was greater in the pain-threshold group at RTP clearance by 15% (95% CI = 1 to 28) and by 15% (95% CI = 1 to 29) at two-month follow-up. BFlh fascicles were 0.91cm (95% CI = 0.34 to 1.48) longer at two-month follow-up in the pain-threshold group. Two re-injuries occurred in both the pain-free and pain-threshold group during six-month follow-up. Pain-threshold rehabilitation did not accelerate RTP clearance but did result in greater recovery of isometric knee flexor strength and better maintenance of BFlh fascicle length improvements compared to pain-free rehabilitation. J Orthop Sports Phys Ther, Epub 28 Jun 2019. doi:10.2519/jospt.2019.8895.

Hamstring Injuries: Risk Factors, Treatment, and Rehabilitation.

➤ The most predictive factor for hamstring injury is a previous hamstring injury.➤ Magnetic resonance imaging is the most useful study for determining the extent of the hamstring injury and whether surgical intervention is warranted.➤ Conservative treatment is indicated for acute hamstring strains, partial tears, and single-tendon avulsions.➤ Surgical repair of complete proximal hamstring ruptures, both acute and chronic, results in improved outcomes compared with nonoperative management.➤ Repair of acute proximal hamstring tendon tears results in better functional outcomes than repair of chronic tears.➤ Stretching and strengthening the hamstring tendons with eccentric exercise is useful for physical therapy after injury and may reduce the risk of reinjury.

The acute and post-activation potentiation effects of the SPEEDMAKER™ on step-by step kinematics, muscle activation and performance in 30-m sprints

The purpose of this study was to examine the acute effects of using the SpeedMaker™ on step-by-step kinematics and muscle activity in 30-m sprints and if it is possible to elicit a post-activation potentiation stimulus with the SpeedMaker™ upon subsequent 30-m sprint performance. Thirteen male soccer players (age: 22.8±1.8 yr, body mass: 75.1±11.9 kg, height: 1.80±0.08 m) participated in a repeated measure and cross-over design consisting of two conditions: three normal 30-m sprints (control) and two normal 30-m sprints divided by one 30-m sprint with the SpeedMaker™ (intervention). Kinematics were measured for each step together with the peak muscle activity of the hamstrings, quadriceps and gluteus during each stride of each 30-m sprint. The main findings were that sprinting with the SpeedMaker™ increased sprint times by 1.7% compared to normal 30-m sprints. However, no occurrence of a postactivation potentiation (PAP) response was found when performing a 30-m sprint with the SpeedMaker™ prior to a normal 30-m sprint in male soccer players. Furthermore, no detectable differences in step-by-step analysis on kinematics and muscle activity were found between the sprints with and without the SpeedMaker™. Only hamstrings and gluteus activity increased per stride over 30-m. It was concluded that the SpeedMaker™ did influence sprint times, but only in a small way that kinematics and muscle activity did not change detectable. Furthermore, that the SpeedMaker™ did not elicit a PAP effect. In addition, increased hamstring and gluteus maximus activation during the 30-m sprints suggests that these muscles are very important for acceleration, and that it is likely that acute hamstring strains occur when a soccer player is close to maximal velocity, as hamstring activation is maximal at that point.

Pain-free vs pain-threshold rehabilitation for acute hamstring strain injury: A randomised controlled trial

Background: Hamstring strain injury (HSI) remains the most prevalent cause of time lost from competition in many sports. Deficits in hamstring muscle structure and function following return to play (RTP) clearance and increased re-injury risk in those with a previous HSI, suggest inadequacies in current rehabilitation practices. Conventional clinical guidelines for acute HSI recommend rehabilitation only continue and progress in the absence of pain, despite a lack of scientific comparisons to alternative approaches. The purpose of this study was to investigate whether allowing rehabilitation up to a pain-threshold compared to remaining pain-free alters time taken to achieve RTP clearance, hamstring muscle structure and function and rates of re-injury following acute HSI.

The effects of cryotherapy versus cryostretching on clinical and functional outcomes in athletes with acute hamstring strain

PurposeHamstring strain is a common sport injury that results in pain and functional limitation. Despite its high frequency in active populations, there is no agreement regarding the best method used for early intervention of hamstring strain. The aim of the present study was to compare the effects of cryotherapy and cryostretching on clinical and functional outcomes in athletes with acute hamstring strain. Materials and methodsThirty seven elite athletes with an acute grade I or II hamstring strain were randomly assigned to either cryotherapy (n = 19) or cryostretching (n = 18) group, receiving 5 sessions of supervised treatment plus home-based intervention monitored by the therapist. Pre-treatment to post-treatment changes in pain, active and passive knee extension range of motion and functional status were compared between the two groups. ResultsCompared to cryotherapy, cryostretching resulted in larger improvement of function and passive knee extension range of motion. Changes in active knee extension range of motion and pain severity were not significantly different between the two groups. ConclusionA rehabilitation protocol involving gentle stretching following cryotherapy is more effective than cryotherapy alone in the improvement of function and passive knee range of motion in patients with grade I and II hamstring strain.

Hamstring Injuries in the Athlete: Diagnosis, Treatment, and Return to Play.

Hamstring injuries are very common in athletes. Acute hamstring strains can occur with high-speed running or with excessive hamstring lengthening. Athletes with proximal hamstring tendinopathy often do not report a specific inciting event; instead, they develop the pathology from chronic overuse. A thorough history and physical examination is important to determine the appropriate diagnosis and rule out other causes of posterior thigh pain. Conservative management of hamstring strains involves a rehabilitation protocol that gradually increases intensity and range of motion, and progresses to sport-specific and neuromuscular control exercises. Eccentric strengthening exercises are used for management of proximal hamstring tendinopathy. Studies investigating corticosteroid and platelet-rich plasma injections have mixed results. Magnetic resonance imaging and ultrasound are effective for identification of hamstring strains and tendinopathy but have not demonstrated correlation with return to play. The article focuses on diagnosis, treatment, and return-to-play considerations for acute hamstring strains and proximal hamstring tendinopathy in the athlete.