scholarly journals Assessment of knee flexor muscles strength in patients with patellar instability and its clinical implications for the non-surgical treatment of patients after first patellar dislocation - pilot study

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Krzysztof Małecki ◽  
Jarosław Fabiś ◽  
Paweł Flont ◽  
Anna Fabiś-Strobin ◽  
Kryspin Niedzielski
Keyword(s):  
Knee Flexion ◽  
Patellar Dislocation ◽  
Patellar Instability ◽  
Peak Torque ◽  
Recurrent Patellar Dislocation ◽  
Hamstring Muscles ◽  
Flexor Muscles ◽  
First Time ◽  
Knee Flexors ◽  
Significant Weakness

Abstract Background Biomechanical studies indicate that during outward rotation of the tibia and the valgus knee joint position, the patella is shifted in the lateral direction. After first-time patellar dislocation, the dynamic position of the femur in relation to the tibia plays an important role in joint stability, because the medial stabilizer of the patella (mostly the MPFL) is damaged or inefficient. The most important factor in controlling the rotational movement of the tibia in relation to the thigh are the hamstring muscles. The aim of the study therefore is to determine whether patients with patellar instability have a significant weakness in the knee flexor muscles, which can predispose to recurrent dislocations. This is an important consideration when planning the rehabilitation of patients with first-time patellar dislocation. Methods The study enrolled 33 patients with confirmed recurrent patellar dislocation, including six patients with bilateral involvement. In the study group, the hamstring muscles (both sides) were evaluated at velocities of 60 and 180 deg/s for the following parameters: peak torque, torque at 30 degrees of knee flexion, angle of peak torque and peak torque hamstring to quadriceps ratio (H/Q ratio). Results In the recurrent patellar dislocation group, a statistically significant weakness in knee flexors was observed for both angular velocities compared to age and gender normative data. No such relationship was observed in the control group of heathy subjects. In patients with one-sided dislocation, no differences were found in knee flexors peak torque, torque at 30 degrees of knee flexion, angle of peak torque or H/Q ratio between the healthy and affected limbs for either angular velocity. Conclusions In patients with recurrent patellar dislocation, knee flexors strength is decreased significantly in both the unaffected and affected limbs. This may indicate a constitutional weakening of these muscles which can predispose to recurrent dislocations. Trial registration The study was retrospectively registered on ClinicalTrials.gov (NCT04838158), date of registration; 22/03/2021.

scholarly journals The Results of Adductor Magnus Tenodesis in Adolescents with Recurrent Patellar Dislocation

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Krzysztof Malecki ◽  
Jaroslaw Fabis ◽  
Pawel Flont ◽  
Kryspin Ryszard Niedzielski
Keyword(s):  
Children And Adolescents ◽  
Patellar Dislocation ◽  
Peak Torque ◽  
Recurrent Dislocation ◽  
Quadriceps Muscle ◽  
Pain Scale ◽  
Mpfl Reconstruction ◽  
Recurrent Patellar Dislocation ◽  
Adductor Magnus ◽  
First Time

Recurrent dislocation of the patella is a common orthopaedic problem which occurs in about 44% of cases after first-time dislocation. In most cases of first-time patellar dislocation, the medial patellofemoral ligament (MPFL) becomes damaged. Between 2010 and 2012, 33 children and adolescents (39 knees) with recurrent patellar dislocation were treated with MPFL reconstruction using the adductor magnus tendon. The aim of our study is to assess the effectiveness of this surgical procedure. The outcomes were evaluated functionally (Lysholm knee scale, the Kujala Anterior Knee Pain Scale, and isokinetic examination) and radiographically (Caton index, sulcus angle, congruence angle, and patellofemoral angle). Four patients demonstrated redislocation with MPFL graft failure, despite the fact that patellar tracking was found to be normal before the injury, and the patients had not reported any symptoms. Statistically significant improvements in Lysholm and Kujala scales, in patellofemoral and congruence angle, were seen(P<0.001). A statistically significant improvement in the peak torque of the quadriceps muscle and flexor was observed for 60°/sec and 180°/sec angular velocities(P=0.01). Our results confirm the efficacy of MPFL reconstruction using the adductor magnus tendon in children and adolescents with recurrent patellar dislocation.

Risk assessment and management of primary patellar dislocation is complex and multifactorial: a survey of Australian knee surgeons

2021 ◽  
pp. jisakos-2020-000609
Author(s):  
Lachlan S Huntington ◽  
Kate E Webster ◽  
Brian M Devitt ◽  
Julian A Feller
Keyword(s):  
Patellar Dislocation ◽  
Patellar Instability ◽  
Surgical Intervention ◽  
Decision Making Process ◽  
Recurrent Patellar Dislocation ◽  
Surgical Decision ◽  
Risk Of Recurrence ◽  
History Of ◽  
First Time ◽  
Surgical Decision Making

ObjectivesRecurrent patellar instability following first-time lateral patellar dislocation is associated with a variety of bony, soft tissue and patient-related risk factors. The specific management of recurrent dislocation may vary depending on the presence and combination of these factors as well as the treating physician’s interpretation of these. Therefore, this study aimed to determine which factors Australian knee surgeons regard as increasing the risk of recurrence following first-time patellar dislocation and to characterise the surgical decision-making process of these surgeons in the management of lateral patellar instability.MethodsAn online survey was sent to all active members of the Australian Knee Society (AKS). The survey addressed (i) risk factors for recurrence following first-time patellar dislocation and (ii) the surgical decision-making process in treating patellar instability.ResultsSeventy-seven per cent (53 of 69) Australian Knee Society members responded. Factors identified by respondents as significantly increasing the risk of recurrence were a history of contralateral recurrent patellar dislocation (74% respondents), an atraumatic injury mechanism (57%), trochlear dysplasia (49%) younger age (45%), patella alta (43%) and generalised ligamentous laxity (42%). Forty-four per cent replied that there may be an indication for surgical intervention following first-time patellar dislocation with no apparent loose body present. All respondents would recommend operative management of recurrent patellar dislocation after a third episode, with 45% of surgeons recommending surgery after a second episode. The most common surgical procedures performed by respondents were medial patellofemoral ligament (MPFL) reconstruction (94%), tibial tuberosity medialisation (91%) and tibial tuberosity distalisation (85%). Only 23% of respondents consider trochleoplasty for primary surgical intervention.ConclusionSurgeons identified a large number of factors that they use to assess risk of recurrence following first-time patellar dislocation, many of which are not supported by the literature. The two highest ranked factors (history of contralateral recurrent patellar dislocation and an atraumatic injury mechanism) are without a significant evidence base. There was considerable variation in the criteria used to make the decision to perform a patellar stabilisation procedure. MPFL reconstruction was the most commonly used procedure, either in isolation or combined with another procedure.Level of evidenceCross-sectional study; expert opinion (Level V).

Risk Factors and Time to Recurrent Ipsilateral and Contralateral Patellar Dislocations

2017 ◽  
Vol 45 (9) ◽  
pp. 2105-2110 ◽  
Author(s):  
Tyson C. Christensen ◽  
Thomas L. Sanders ◽  
Ayoosh Pareek ◽  
Rohith Mohan ◽  
Diane L. Dahm ◽  
...  
Keyword(s):  
Risk Factors ◽  
Cumulative Incidence ◽  
Patellar Dislocation ◽  
Patellar Instability ◽  
Trochlear Dysplasia ◽  
Patella Alta ◽  
Time To Recurrence ◽  
Lateral Patellar Dislocation ◽  
Ipsilateral Recurrence ◽  
First Time

Background: Previous studies have reported variable rates of recurrent lateral patellar instability mainly because of limited cohort sizes. In addition, there is currently a lack of information on contralateral patellar instability. Purpose: To evaluate the rate of recurrent ipsilateral patellar dislocations and contralateral patellar dislocations after a first-time lateral patellar dislocation. Additionally, risk factors associated with recurrent dislocations (ipsilateral or contralateral) and time to recurrence were investigated. Study Design: Cohort study; Level of evidence, 3. Methods: This population-based study included 584 patients with a first-time lateral patellar dislocation occurring between 1990 and 2010. A retrospective review was conducted to gather information about the injury, subsequent dislocations (ipsilateral or contralateral), and structural characteristics including trochlear dysplasia, patella alta, and tibial tubercle to trochlear groove (TT-TG) distance. Risk factors were assessed to delineate associations with subsequent dislocations and time to recurrence. Results: At a mean follow-up of 12.4 years, 173 patients had ipsilateral recurrence, and 25 patients had a subsequent contralateral dislocation. At 20 years, the cumulative incidence of ipsilateral recurrence was 36.0%, while the cumulative incidence of contralateral dislocations was 5.4%. Trochlear dysplasia (odds ratio [OR], 18.1), patella alta (OR, 10.4), age <18 years at the time of the first dislocation (OR, 2.4), elevated TT-TG distance (OR, 2.1), and female sex (OR, 1.5) were associated with recurrent ipsilateral dislocations. Time to recurrence was significantly decreased in patients with trochlear dysplasia (23.0 months earlier time to recurrence; P < .001), elevated TT-TG distance (18.5 months; P < .001), patella alta (16.4 months; P = .001), and age <18 years at the time of the first dislocation (15.4 months; P < .001). Risk factors for subsequent contralateral dislocations included patella alta and trochlear dysplasia. Conclusion: At 20 years after a first-time lateral patellar dislocation, the cumulative incidence of recurrent ipsilateral patellar dislocations was 36.0%, compared with 5.4% for contralateral dislocations. Trochlear dysplasia, elevated TT-TG distance, patella alta, age <18 years at the time of the first dislocation, and female sex were associated with ipsilateral recurrence. Trochlear dysplasia, elevated TT-TG distance, patella alta, and age <18 years at the time of the first dislocation were predictive of a statistically significant decrease in time to recurrence.

scholarly journals DESCRIPTIVE EPIDEMIOLOGY STUDY OF THE JUSTIFYING PATELLAR INSTABILITY TREATMENT BY EARLY RESULTS (JUPITER) COHORT

2019 ◽  
Vol 7 (3_suppl) ◽  
pp. 2325967119S0004 ◽  
Author(s):  
Meghan E. Bishop ◽  
Jacqueline M. Brady ◽  
Daphne Ling ◽  
Shital Parikh ◽  
Beth E. Shubin Stein
Keyword(s):  
Operative Treatment ◽  
Prospective Cohort ◽  
Patellar Dislocation ◽  
Patellar Instability ◽  
Group Versus ◽  
Physical Exam ◽  
Patient Demographics ◽  
Early Results ◽  
Patient Reported ◽  
First Time

Background: Patellar instability is frequently seen in young patients and can lead to significant disability and arthritis. Its management is controversial. JUPITER (Justifying Patellar Instability Treatment by Early Results) is a hypothesis-driven, multi-center, multi-armed, prospective cohort study developed to obtain sufficient subjects to better describe clinical characteristics and predictors of clinical outcomes in the young patellar instability population. The purpose of this study is to describe the formation of JUPITER and provide preliminary descriptive analysis of patient demographics and clinical features for the initially enrolled patients in this prospective cohort. Methods: After training and institutional review board approval, surgeons began enrolling patients from the 10-25 years age group who sustained a patellar dislocation or subluxation event. Information regarding patient demographics, dislocation history, physical exam characteristics, and baseline validated patient reported outcome scores were collected. Results: As of May 31, 2018, 20 surgeons from 9 different sites had prospectively enrolled a total of 406 patients (142 male, 262 female, 2 not listed; average age 15.1 years old). 269 patients were enrolled in the operative group and 137 patients in the non-operative group. 54.7% of patients reported that they had had greater than 1 dislocation (71.7% in the operative group; 20.4% in the non-operative group). The mean number of recurrent dislocations was 7.6 (Mean operative group 8.3 vs. non-operative group 3.5). 58.7% of first time dislocators were indicated for non-operative treatment while 13.1% of recurrent dislocators were indicated for non-operative treatment (95% CI: 39.1-55.3%, p<0.0001). At the time of first dislocation, 46.3% of participants reported they were participating in a sporting activity, 10.1% were walking, 6.2% were running, 2% were on stairs, and 31.3% reported other activity. 16.7% of the operative group versus 21.2% of the non-operative group reported a contact injury at the time of first dislocation. 32.5% required a manual reduction. Of those who sustained a recurrent dislocation, 5.4% reported a contact injury while 82.4% reported non-contact injury and 9.9% were unsure. 20.7% reported a family history of patellar dislocation. On physical exam, 51.2% (190/369) of patients were noted to have a positive J sign in the involved knee (78.4% mild, 21.2% severe). 35.2% (126/358) were noted to have Beighton hypermobility scores greater than 4. In a multivariable logistic regression model, more severe J-sign was associated with higher odds of redislocation (OR=2.76, 95% CI: 1.60-4.75, p<0.0001) and higher Beighton scores approached significance (OR=1.10, 95% CI: 1.00 -1.20, p=0.06). Pedi-FABS scores (12.5 vs 14.9, p=0.02) and KOOS QOL scores (35.5 vs 41.5, p=0.01) were significantly lower in those who experienced more than one redislocation. Kujala scores were higher in the recurrent dislocators (60.1 vs 55.3, p=0.04). Conclusions: The JUPITER Group has been able to accumulate the largest prospectively collected patellar instability database to date. Over half of patients in this group reported they sustained more than one dislocation. Almost 60% of first time dislocators were indicated for nonsurgical management while only 13% of recurrent dislocators were indicated for non-operative management. Over 80% of recurrent dislocations occurred during a non-contact event. Pedi-FABS scores and KOOS QOL scores were significantly lower in those who experienced more than one redislocation.

scholarly journals Isokinetic Strength Responses to Season-long Training and Competition in Turkish Elite Soccer Players

2012 ◽  
Vol 31 (1) ◽  
pp. 159-168 ◽  
Author(s):  
Niyazi Eniseler ◽  
Çağatay Şahan ◽  
Hikmet Vurgun ◽  
Hasan Mavi
Keyword(s):  
Knee Extensor ◽  
Peak Torque ◽  
Soccer Players ◽  
Isokinetic Strength ◽  
Professional Soccer ◽  
Knee Strength ◽  
Flexor Muscles ◽  
Angular Velocities ◽  
Soccer Training ◽  
Knee Flexors

Isokinetic Strength Responses to Season-long Training and Competition in Turkish Elite Soccer PlayersThere are not enough studies that describe the isokinetic strength of professional soccer players at high angular velocities. The purpose of this study was to evaluate the seasonal changes in isokinetic strength of Turkish professional soccer players (n=14) over the course of a 24-week soccer season. The isokinetic strength of players who underwent usual soccer training and weekly competition throughout the soccer season was assessed by means of the Biodex System 3 dynamometer with the knee attachment. The peak torque of knee extensor and flexor muscles were measured at angular velocities of 60°/s, 300°/s and 500°/s. Players were tested at the beginning and end of the competitive season. While the first- and second-test measurements did not show significant changes at 60°/s and 300°/s angular velocities, at the end of the training period, players' knee strength changed significantly at 500°/s angular velocities. In addition, the H/Q ratio improved significantly for the dominant as well as non-dominant leg at 500°/s. Significant bilateral strength improvements for knee flexors were also observed at 500°/s. The findings of this study suggest that usual daily soccer training (technical, tactical, power, strength, endurance, flexibility, etc.) and weekly competition might produce changes in knee strength at high angular velocities.

scholarly journals Hamstring Torque, Velocity and Power Elastic Band Measurements during Hip Extension and Knee Flexion

2021 ◽  
Vol 11 (22) ◽  
pp. 10509
Author(s):  
Dario Santos ◽  
Fernando Massa ◽  
Jorge Dominguez ◽  
Isabel Morales ◽  
Juan Del Castillo ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Peak Torque ◽  
Dynamic Monitoring ◽  
Normative Values ◽  
Elastic Band ◽  
Open Chain ◽  
Elastic Resistance ◽  
Hamstring Muscles ◽  
The Difference ◽  
Hip Extension

The quantitative dynamic monitoring of the performance of hamstring muscles during rehabilitation and training cannot currently be undertaken using elastic resistance bands. Hip extension with a fully extended knee involves hamstring agonists, while knee flexion involves only the hamstring. The purpose of this study is to provide normative values of torque, velocity and power involving hamstring muscles opposing elastic bands. Twenty amateur athletes aged 25.7 ± 4.9, were studied during two motor tasks—hip extension and knee flexion, both isometric & dynamic—with an elastic resistance band and DINABANG portable instrument. We compared the peak isometric torque in hip extension with agonists (2.93 Nm/kg) and without them (1.21 Nm/kg): the difference is significant. The peak angular limb velocity—starting at 50% of the maximum torque—is smaller in hip extension with agonists (215.96°/s) than in a knee flexion without them (452.56°/s). The combination of peak torque and peak velocity estimates power and there is no difference (p = 0.051) with and without agonists: 452.56°Nm/s.kg without agonists and 542.13°Nm/s.kg with them. This study opens the possibility of monitoring torque–velocity–power profiles for hamstring exercise in open chain.

scholarly journals Familial patellar dislocation associated with t(15;20) (q24;q13.1)

2018 ◽  
Vol 26 (2) ◽  
pp. 230949901877702 ◽  
Author(s):  
CM Jimmy Chan ◽  
YM Jackie Chau ◽  
SB Woo ◽  
HM Luk ◽  
Ivan FM Lo
Keyword(s):  
Short Stature ◽  
Patellar Dislocation ◽  
Patellar Instability ◽  
Autosomal Dominant ◽  
Knee Injuries ◽  
Recurrent Patellar Dislocation ◽  
Balanced Translocation ◽  
Three Generations

Patellar instability is a common debilitating injury affecting young active individuals. It accounts for approximately 3% of all knee injuries. We report a family, of which five members across three generations, who suffered from autosomal dominant familial recurrent patellar dislocation as well as short stature. All of them have recurrent patellar dislocations before the age of 15. The affected patients in all three generations have been genetically screened. Genotypical evaluation revealed a balanced translocation of chromosomes 15 and 20.

scholarly journals Determination of the isokinetic muscle strength profile of knee flexors and extensors in visually impaired long-distance athletes: Pilot studyGörme engelli uzun mesafe atletizm sporcularında diz fleksör ve ekstansörlerinin izokinetik kas kuvvet profilinin belirlenmesi: Pilot çalışma

2017 ◽  
Vol 14 (2) ◽  
pp. 2111
Author(s):  
Tuğba Kocahan ◽  
Bihter Akınoğlu ◽  
Çağlar Soylu ◽  
Necmiye Ün Yıldırım ◽  
Adnan Hasanoğlu
Keyword(s):  
Muscle Strength ◽  
Knee Flexion ◽  
Visually Impaired ◽  
Peak Torque ◽  
Long Distance ◽  
Long Distance Running ◽  
The Right ◽  
Dominant Side ◽  
Knee Flexors ◽  
Flexion And Extension

Purpose: The aim of this study is to determine the isokinetic muscle strength profile of knee flexor and extensor muscles of visually impaired long distance running athletes and compare them with the literature.Methods: The study consisted of 7 male visually impaired long distance running athletes aged between 19-28 (means 24,14±3,23), who complied with the criteria and voluntarily participated in the study. İsokinetic measurement was performed with Isomed 2000® device. İn isokinetic evaluation, maximal muscle strength, muscle strength ratios, percentage of right-left strength difference ratio of knee flexors and extensors were recorded. İsokinetic testing protocol; before the test all athletes performed the knee flexion and extension isokinetic test with the 5 repeating at 90 º/sec as a warm-up and for comprehenting the test. Then, knee flexion and extension concentric-concentric strength measurements were performed with the 5 repeating at 60 º/sec and with the 15 repeating at 180 º/sec with the angle between 90 degrees of knee flexion and 10 degrees of knee extension. The evaluations were performed bilaterally, first dominant side and after 3 minutes non dominant side was evaluated.Results: The H / Q peak torque ratio of the athletes is 53.55% for the dominant side and 55.47% for the non-dominant side at 60º / sec. velocity while 59.05% for the dominant side and 61.34% for the non-dominant side at 180º / sec. velocity. When the H / Q peak torque ratio of the athletes was compared between dominant and non-dominant sides, there was no difference in both angular velocities (p>0.05). Knee flexion and extension isokinetic muscle strength’s difference were determined lower than %10 for both angular angles when compared to the asymmetry of the right and left extremities. It was found that this was in accordance with the literature and there was no asymmetry between the right and left sides.Conclusion: In visually impaired long distance runners, having H/Q ratio lower than normal borders against knee flexors for both sides at 180°/sec. angular velocity poses a risk for injuries. In terms of prevention of sports injuries, it is necessary for the athletes to maintain muscle force balance which is specific to each angular velocity and to exercise with sports-specific exercises.Extended English abstract is in the end of PDF (TURKISH) file.ÖzetAmaç: Bu çalışmanın amacı görme engelli uzun mesafe atletizm sporcularının diz fleksör ve ekstansör kaslarının izokinetik kas kuvvet profilini belirlemek ve literatürdeki bilgilerle karşılaştırmaktır.Method: Çalışmamıza; 19-28 (Ort. 24,14±3,23) yaş aralığında 7 erkek görme engelli uzun mesafe atletizm sporcusu dâhil edildi. İzokinetik kas kuvveti Isomed 2000® cihazı ile değerlendirildi. İzokinetik değerlendirmede diz fleksör ve ekstansörlerinin maksimum kas kuvveti, kas kuvvet oranları, sağ-sol kuvvet farkı oranı yüzdesi kaydedildi. Değerlendirmede 90-10 º fleksiyon açılarında konsantrik-konsantrik kuvvet ölçümü yapıldı. İzokinetik test protokolü olarak; 5 tekrarlı 90º/sn. hızla testi anlama ve submaksimal ısınma hareketinden sonra, 5 tekrarlı 60º/sn. hızla ve 15 tekrarlı 180º/sn. hızla maksimal diz fleksiyon ve ekstansiyon hareketleri yaptırıldı. Değerlendirmeler bilateral olarak gerçekleştirildi ve öncelikle dominant taraf, 3 dk sonra non-dominant taraf değerlendirildi.Bulgular: Sporcuların H/Q peak tork oranı 60º/sn. hızda dominant taraf için % 53.55, non-dominant taraf için % 55.47 bulunurken 180º/sn. hızda dominant taraf için % 59.05, non-dominant taraf için % 61.34 bulundu. H/Q peak tork oranı dominant ve non-dominant taraf arasında karşılaştırıldığında her iki açısal hızda da farklılık bulunmadı (p>0,05). Sağ ve sol ekstremiteler asimetri açısından karşılaştırıldığında diz fleksiyon ve ekstansiyon izokinetik kas kuvveti farkının her iki açısal hızda da %10 un altında olduğu belirlendi. Bu durumun literatür ile uyumlu olduğu ve sağ-sol taraf arasında bir asimetri olmadığı sonucuna varıldı.Sonuç: Çalışmamız sonucunda Görme engelli uzun mesafe koşucularında 180º/sn. açısal hızda H/Q oranının normal sınırlardan daha düşük ve her iki tarafta diz fleksörleri aleyhinde olması yaralanma açısından risk oluşturmaktadır. Spor yaralanmalarının önlenmesi açısından sporcuların her açısal hıza özgü olan kas kuvvet dengesinin korunması ve spora özgü egzersizlerle çalıştırılması gereklidir.

scholarly journals Muscle Recruitment Pattern of The Hamstring Muscles in Hip Extension and Knee Flexion Exercises

2020 ◽  
Vol 72 (1) ◽  
pp. 51-59 ◽  
Author(s):  
Osamu Yanagisawa ◽  
Atsuki Fukutani
Keyword(s):  
Knee Flexion ◽  
Biceps Femoris ◽  
Peak Torque ◽  
Total Work ◽  
Recruitment Pattern ◽  
Concentric Contractions ◽  
Hamstring Muscles ◽  
Long Head ◽  
S Peak ◽  
Hip Extension

AbstractWe aimed to compare dynamic exercise performance between hip extension exercises with different knee angles and between knee flexion exercises with different hip angles, and to investigate the recruitment pattern of the hamstrings in each exercise. Seven men performed 4 isokinetic exercises (3 maximal concentric contractions at 30°/s (peak torque) and 30 maximal concentric contractions at 180°/s (total work)): hip extension with the knee fully extended (HEke) and with the knee flexed at 90° (HEkf) and knee flexion with the hip fully extended (KFhe) and with the hip flexed at 90° (KFhf). The recruitment pattern of the hamstrings was evaluated in each exercise using magnetic resonance imaging (T2 calculation). The HEke condition showed significantly greater peak torque than the HEkf condition (p < 0.05). The KFhf condition had significantly greater peak torque and total work values than the KFhe condition (p < 0.05). Although the biceps femoris long head, semitendinosus, and semimembranosus had significantly increased post-exercise T2 values in the HEke (p < 0.05), KFhe, and KFhf conditions (p < 0.01), the T2 increase values were significantly greater under the KFhf than the HEke condition (p < 0.05). The semitendinosus showed a significantly greater T2 increase value than other muscles under both KFhe and KFhf conditions (p < 0.05). Performance of hip extension and knee flexion exercises increases when the hamstring muscles are in a lengthened condition. The hamstring muscles (particularly the semitendinosus) are more involved in knee flexion than in hip extension.

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