Hamstring To Quadriceps Ratio Research Articles

Hamstrings-quadriceps strength ratio could be related to falls in community-living older adults

A prior study reported that the concentric strength imbalance between hamstrings and quadriceps is associated with falls in older adults. Given that the concentric strength may not be measured as conveniently as the isometric strength, it is meaningful to test whether the isometric hamstring-quadricep strength imbalance is related to falls among older adults. This study sought to explore whether the hamstrings-quadriceps ratio could differentiate fallers from non-fallers in community-dwelling older adults. One hundred and eleven older adults were included in this cross-sectional study. Their isometric knee joint strength capacity (extensors and flexors) was measured. Based on their fall history in the past year, they were classified as fallers (at least one fall) or non-fallers (no fall). The hamstrings-quadriceps ratio was compared between the faller and non-faller groups. The receiver operating characteristic analysis was used to determine the cutoff value of the hamstrings-quadriceps ratio able to best classify fallers and non-fallers. Fallers showed a significantly lower hamstrings-quadriceps ratio than non-fallers (p = 0.008). The receiver operating characteristic analysis identified 0.733 as the best ratio to differentiate fallers from non-fallers with an accuracy of 64.0 %. A 0.1-unit reduction in the hamstrings-quadriceps ratio increases the probability of falling by a factor of 1.30. The hamstrings-quadriceps ratio could be used as an additional fall risk factor when assessing the risk of falls among older adults. A smaller than 0.733 hamstring-quadriceps ratio may indicate a high risk of falls.

Tibiofemoral bone configuration is not associated with hamstring muscle strength in male and female patients with ACL reconstruction.

Previous evidence indicated that the tibiofemoral bone configuration might elevate the risk of an anterior cruciate ligament (ACL) injury. Furthermore, a low hamstring-to-quadriceps muscle ratio predisposes especially females to unfavourable knee kinematics. The primary objective of the present study was to investigate sex-specific associations between tibiofemoral bone geometry and isokinetic knee flexion torque in patients with primary ACL injury followed by ACL reconstruction. N = 100 patients (72 = male, 28 = female, age = 31.3 ± 10.2, body mass index = 25.3 ± 3.6) with primary ACL rupture with isokinetic knee flexion torque assessments before and 6 months after ACL reconstruction surgery were analysed. Magnetic resonance imaging scans were analysed for medial posterior tibial slope (MPTS) and lateral posterior tibial slope, notch width index (NWI) and lateral femoral condyle index (LFCI). Additionally, isokinetic knee flexion torque (60°/s) and hamstring-quadriceps ratios were evaluated. Subsequently, functional parameters were correlated with imaging data for gender subgroups. The findings showed that presurgical isokinetic knee flexion torque was not associated with any marker of femoral or tibial bone geometry. Further, while significant differences were observed between female (0.883 ± 0.31 Nm/kg) and male (1.18 ± 0.35 Nm/kg) patients regarding preoperative normalized knee flexion torque (p < 0.001), no significant sex differences were found for percentage increases in normalized knee flexion torque from presurgery to postsurgery. Generally, female patients demonstrated significantly higher MPTS magnitudes (p < 0.05) and lower LFCI values (p < 0.05) compared to men. The present results demonstrated no association between tibial or femoral bone geometry and muscle strength of the hamstrings in patients with ACL reconstruction, indicating an important mismatch of muscular compensation to deviations in bone geometry. There were no sex-specific differences in tibiofemoral bone parameters. Level III.

Favorable Patient-Reported, Clinical, and Functional Outcomes 2 Years After ACL Repair and InternalBrace Augmentation Compared With ACL Reconstruction and Healthy Controls

Background: Recently, interest in anterior cruciate ligament (ACL) preservation and repair after proximal ACL tears has been resurrected. Although good clinical outcomes have been reported in the literature with adequate patient selection, to date detailed scientific evidence for the functional benefit of primary ACL repair with ligament augmentation is scarce. Purpose: To compare patient-reported, clinical, and functional outcomes in patients 2 years after ACL repair and InternalBrace augmentation (ACL-IB) with age- and sex-matched patients 2 years after ACL reconstruction (ACL-R) and with matched healthy controls. Study Design: Cohort study; Level of evidence, 3. Methods: In total, 29 patients 2 years after ACL-IB, 27 sex- and age- matched patients 2 years after ACL-R (hamstring autografts), and 29 matched healthy controls were included. Patient-reported outcomes were assessed using the International Knee Documentation Committee score, Knee injury and Osteoarthritis Outcome Score, EQ-5D-5L, Tegner Activity Scale, and Anterior Cruciate Ligament Return to Sports after Injury scale. Surgery time was recorded. For clinical outcomes, range of motion and thigh and shank circumference were measured, and passive anterior translation was determined using the Rolimeter. Isokinetic muscle strength was measured using a Biodex dynamometer. The limb symmetry index (operated/contralateral or nondominant/dominant × 100), side-to-side differences (operated – contralateral, nondominant – dominant), and hamstring-quadriceps ratios were calculated for functional parameters. Failure and reoperation rates were not compared. Results: Two years after surgery, patients treated with ACL-IB showed good to excellent patient-reported outcomes comparable with those of patients after ACL-R. Surgery time, including concomitant surgeries, was significantly shorter in the ACL-IB group (mean, 81 minutes) compared with the ACL-R group (mean, 97 minutes) (P = .024). Isokinetic muscle strength was comparable between patient groups without significant differences in extensor and flexor strength or in hamstring-quadriceps ratios. Conclusion: These results suggest that ACL-IB achieves comparable patient-reported, clinical, and functional outcomes with ACL-R at 2 years postoperatively and, after careful patient selection, should be considered as a valuable early treatment alternative for proximal ACL tears. Registration: NCT04429165 (ClinicalTrials.gov identifier).

Isolated radial tears of the lateral meniscus midbody: a case series of professional athletes treated with outside-in repair.

The main aim of the study is to assess clinical and functional outcomes of arthroscopic outside-in repair of isolated radial tears of the midbody of lateral meniscus in professional athletes and to evaluate the return to the sport activity after surgery. A retrospective data collection on professional athletes with isolated complete lesion of the midbody of lateral meniscus, treated with arthroscopic outside-in repair was carried out. Outcome measures included functional assessment, Limb Symmetry Index (LSI) and Hamstring Quadriceps Ratio (HQR) and Lysholm score collected before surgery and at 4-month follow-up. Data on return to sport practice and re-injury were also retrieved. Fourteen patients satisfied the selection criteria. Full return to professional sport activity (Tegner 10) was registered in the 86% of the cohort at 4months after the surgery. Functional testing of the athletes showed a return of the LSI and HQR to the pre-surgical condition, demonstrating a full recovery of the functional ability and muscle strength. Similarly, clinical evaluation through Lysholm score showed an improvement, reaching an average of 97.7 points at 4months follow-up. A good functional recovery and a high rate of return to play has been observed in a population of professional athletes, at 4months after outside-in repair.

Musculoskeletal Asymmetry in Young Soccer Players: Differences between the Dominant and Nondominant Leg

The purpose of this investigation was to clarify the differences in the musculoskeletal profiles between the dominant leg (DL) and nondominant leg (NDL) of Japanese soccer players. This study included 227 young elite soccer players (121 males and 106 females with mean ages of 19.0 and 17.5 years, respectively). Anthropometric measurements were obtained. In addition, joint range of motion measurements was performed for internal rotation of the hip, ankle dorsiflexion, and knee extension. Muscle flexibility tests were performed on the iliopsoas, quadriceps femoris, hamstring, gastrocnemius, and soleus muscles. Moreover, isometric knee extension, flexion strength, and isometric hip abduction strength were measured. Single-leg balance tests were also performed. As a result, in male soccer players, DL's knee flexor strength and hip abductor strength were significantly stronger than in the NDL. In female soccer players, knee extension and knee flexion strength of the DL were significantly stronger than the NDL. In male soccer players, the hamstring-quadriceps ratio of the DL was significantly greater than NDL. DL demonstrated a significantly lesser center of pressure excursion in the single-leg balance test in male and female soccer players. In both male and female soccer players, the quadriceps muscle of DL was significantly more flexible than those of the NDL. There was no difference in the internal rotation angle of the hip joint between the DL and NDL in male soccer players. In contrast, the internal rotation angle of the DL was significantly (1.6°) greater than NDL in female soccer players. For some anthropometric measurements, muscle flexibility tests and joint range of motion measurements, the difference between the DL and NDL was significant but not large enough to be clinically relevant. In conclusion, the present study showed musculoskeletal asymmetry between the DL and NDL in young male and female soccer players.

Comparison of hamstring quadriceps strength ratios in different combat sports branches

Background and Study Aim. The hamstring and quadriceps muscles can have strength differences because of the sportive activities. It is known that sportive hamstring quadriceps strength imbalance can cause decreasing sportive performance and injuries. Also, each sports branch can have a specific effect on the hamstring quadriceps strength ratio. Therefore, the aim of this study was to examine the effects of different combat sports branches on the hamstring quadriceps ratio. &#x0D; Material and Methods. Wrestlers (N=10), boxers (N=10), wushu athletes (N=10) voluntarily participated in the study (also university students). Subjects were administered standard warm-up and then a strength measurement test was performed. Subjects performed knee extensor (quadriceps) and flexor (hamstring) isokinetic strength test (concentrically) with his dominant leg at 60° angular velocity with by Cybex device (Cybex NORM®. Humac. CA. USA). Peak and average strength were recorded automatically by the device. The SPSS package program was used in the analysis of the data. The isokinetic strength measurements of three groups were analyzed with one-way ANOVA.&#x0D; Results. There were no significant differences between groups’ peak isokinetic strength ratio (wrestlers 0.58±0.09 boxers 0.56±0.07 and wushu athletes 0.57±0.12). Also, the average isokinetic strength ratio was not significantly different (wrestlers 0.56±0.08. boxers 0.60±0.08 and wushu athletes 0.53±0.11).&#x0D; Conclusions. According to the results, it can be said that combat sports athletes' hamstring quadriceps ratio can be affected by their sports branches, also by characteristics and training levels.

Correlation Between Y-Balance Test and Balance, Functional Performance, and Outcome Measures in Patients Following ACL Reconstruction.

BackgroundThe Y-Balance test (YBT) is commonly used to evaluate balance after anterior cruciate ligament reconstruction (ACLR). However, several studies have also used it as a functional performance test (FPT).PurposeThis study aimed to examine the relationship between YBT scores and measures of knee joint laxity, static balance, knee flexor and extensor torque and strength ratio, and FPTs.Study DesignRetrospective cohort study.MethodsFifty-nine patients who underwent ACLR using hamstring autografts were retrospectively analyzed. The Pearson correlation coefficient was used to determine the strength of the association between scores on the YBT and selected outcomes including laxity measured via the KT-2000 arthrometer, static balance measured via the Biodex Balance System, isokinetic muscle torque and hamstring-to-quadriceps (HQ) ratio, and performance on the single leg hop test and the single leg vertical jump test.ResultsForty-six men and 13 women were included. The mean age and follow-up period were 29.6 ± 9.6 years and 12.4 ± 2.1 months, respectively. The KT-2000 arthrometer measures, Biodex Balance System scores, and HQ ratio measurements were not significantly correlated with the YBT scores. All YBT scores, except the YBT-anterior score, correlated with the isokinetic extensor and flexor torques (r-values: 0.271–0.520). All the YBT scores had significant weak to moderate correlations with the single leg hop test and single leg vertical jump test scores: YBT-anterior (r = 0.303, r = 0.258), YBT-posteromedial (r = 0.475, r = 0.412), YBT-posterolateral (r = 0.525, r = 0.377), and YBT-composite (r = 0.520, r = 0.412).ConclusionPost-ACLR YBT scores correlated with functional performance and muscle strength, but not with static balance, joint laxity, and HQ ratios. The YBT scores as a measure of balance are related to improved functional performance and isokinetic torque measures.Level of evidence3

Excessive anterior tibial translation in the contralateral uninjured limb is significantly associated with ramp lesion in anterior cruciate ligament injury

PurposeThis study aimed to evaluate the excessive anterior tibial translation (ATT) and muscle strength of patients with ramp lesions. We hypothesised that the higher ATT, lower hamstring-to-quadriceps (HQ) ratio, and higher flexion peak torque influenced by semimembranosus would be associated with ramp lesions.MethodsOne hundred and twenty-one patients who underwent anterior cruciate ligament (ACL) reconstruction were retrospectively evaluated. Clinical evaluation included ATT of the contralateral uninjured limb measured using a KT-1000 arthrometer, the knee flexor and extensor muscle strength of the contralateral uninjured limb at 60°/s and 180°/s of an angular velocity measured using an isokinetic dynamometer, and HQ ratio at 60°/s and 180°/s during the preoperative state. Binary stepwise logistic regression analysis was performed to evaluate the risk factors of ramp lesions.ResultsRamp lesions were found in 27 cases of ACL injuries (27/121, 22.3%). Male sex (odds ratio [OR], 2.913; 95% confidence interval [CI], 1.090–7.787; P = 0.033), longer time between injury to surgery (OR, 2.225; 95% CI, 1.074–4.608; P = 0.031), and higher ATT in the contralateral uninjured limb (OR, 1.502; 95% CI, 1.046–2.159; P = 0.028) were indicated as the independent risk factors of the presence of ramp lesion associated with an ACL injury.ConclusionsMale sex, longer period from injury to surgery, and higher ATT in the contralateral uninjured limb were significantly associated with ramp lesion. These findings are advantageous for identifying patients with a greater risk of developing a ramp lesion with an ACL injury in the clinical setting.Level of evidenceLevel IV

The effect of gracilis tendon harvesting in addition to semitendinosus tendon harvesting on knee extensor and flexor strength after anterior cruciate ligament reconstruction.

Anterior cruciate ligament (ACL) reconstruction using hamstring tendons may involve harvesting of the gracilis tendon in addition to the semitendinosus tendon (ST) depending on the size of the ST graft. However, the effect of gracilis harvesting in addition to ST harvesting on muscle strength, such as the hamstring-to-quadriceps (HQ) ratio, remains unclear. Hence, this study aimed to investigate the effect of gracilis harvesting on subsequent knee muscle strength. Eighty-two patients who underwent ACL reconstruction were included in this retrospective study. They were divided into the following two groups depending on the tendon graft used for ACL reconstruction: the ST group (41 patients) and the semitendinosus tendon/gracilis tendon (STG) group (41 patients). The isokinetic peak torque of the knee extensor and flexor was measured using a BIODEX dynamometer at a velocity of 60°/s and 180°/s, respectively, 3 and 6months after ACL reconstruction. The groups were compared in terms of the limb symmetry index (LSI) and HQ ratio. The significant difference in the knee flexor of the LSI at 6months after ACL reconstruction was as follows: ST group, 120.3 ± 28.3 vs STG group, 105.6 ± 19.0 (p < 0.01) at 60°/s and ST group, 122.9 ± 35.2 vs STG group, 106.2 ± 24.6 (p = 0.02) at 180°/s. There were significant differences in the HQ ratio at 180°/s as follows: ST group, 0.67 ± 0.15 vs STG group, 0.60 ± 0.13 (p < 0.01) at 3months and ST group, 0.67 ± 0.13 vs STG group, and 0.59 ± 0.12 (p < 0.01) at 6months after ACL reconstruction. Gracilis tendon harvesting may contribute to a decrease in knee flexor strength and HQ ratio with fast contraction. Thus, the need for gracilis tendon harvesting in ACL reconstruction should be carefully considered. III.

A comparative study of the acute effects of knee brace vs. kinesiotape on selected isokinetic strength variables of the knee muscles

BACKGROUND: Different methods of treatment for preventing knee injuries, enhancing knee strength and minimising post-injury risks have been explored. Among these methods, Kinesio tape (KT) and knee braces (KB) are commonly used. OBJECTIVE : To investigate the acute effects of KT and KB on isokinetic knee strength parameters. METHODS: A total of 15 healthy sedentary male subjects voluntarily participated in the study. Concentric isokinetic knee extension (EX) and flexion (FLX) strength were measured at three sessions: 1. Baseline 2. with KT (’KT’) 3. with KB (’KB’). Tests were performed at 60, 180 and 240∘/s. Peak moment (PM), Hamstring/Quadriceps ratio (HQR), and joint angle at peak moment (JAPM) were measured. RESULTS: ‘KT’ and ‘KB’ were associated with increase in PMEX, PMFLX, HQR at 60 and 240∘/s (p&lt; 0.05) and increased JAPMEX. No significant difference was observed at 180∘/s (p&gt; 0.05). CONCLUSION: In healthy individuals, ‘I’ shape KT and KB positively affect EX and FLX strengths and HQR, especially at low angular velocity.

Effect of isokinetic training of thigh muscle group on graft remodeling after anterior cruciate ligament reconstruction

To investigate the effect of isokinetic training of thigh muscle group on graft remodeling after anterior cruciate ligament (ACL) reconstruction, and summarize the relevant rules to guide the clinic. Between August 2016 and December 2016, forty patients underwent arthroscopic ACL reconstruction using hamstring tendon were randomly divided into isokinetic group and control group ( n=20). The two groups of patients underwent staged rehabilitation treatment. The isokinetic group replaced the traditional intervention with the corresponding isokinetic strength training from 3 to 6 months after operation, and the traditional rehabilitation intervention was used in the control group. Finally, 12 cases of isokinetic group and 12 cases of control group with complete follow-up were enrolled in study. There was no significant difference in gender, age, body mass index, side of injury, the interval between injury and operation, and preoperative International Knee Documentation Committee (IKDC) score between the two groups ( P>0.05). The peak torque (PT) of knee extension and flexion and hamstring quadriceps ratio (H/Q) were measured at 3 months, 6 months, 12 months, and the second-look arthroscopy. The MRI examination was performed at the same time to evaluate graft remodeling. The shape, tension, and degree of vascularization of grafts were observed under arthroscopy. The grafts were harvested and observed by HE staining. The invertal between ACL reconstruction and the second-look arthroscopy was (23.57±3.23) months in isokinetic group and (23.22±3.56) months in control group, showing no significant difference between the two groups ( P>0.05). At the second-look arthroscopy, the IKDC score was 90.45±4.73 in isokinetic group and 89.32±4.54 in control group, showing significant differences when compared with preoperative scores in the two groups ( P<0.05). But there was no significant difference between the two groups ( t=0.868， P=0.404). At 3 months after operation, there was no significant difference in the PT of knee extension and flexion between the two groups ( P>0.05). At 6 months, 12 months, and the second-look arthroscopy, the PT of knee extension and flexion in isokinetic group were higher than those in control group ( P<0.05). The H/Q at 6 months and 12 months were higher in isokinetic group than in control group, and the differences were significant ( P<0.05). There was no significant difference in MRI score between the two groups at 3 months, 6 months, and the second-look arthroscopy ( P>0.05). The MRI score at 12 months was significantly higher in isokinetic group than in control group ( P<0.05). At the second-look arthroscopy, there was no significant difference in the arthroscopic score between the two groups ( P>0.05), and the histological score of the isokinetic group was superior to the control group ( P<0.05). On the basis of regular rehabilitation training, using the isokinetic training system to develop a suitable post-surgical isokinetic rehabilitation training program is helpful in early muscle strength recovery, early graft remodeling, and even long-term histological results after ACL reconstruction.

The Effect of Hip Extension and Nordic Hamstring Exercise Protocols on Hamstring Strength: A Randomized Controlled Trial.

Whyte, EF, Heneghan, B, Feely, K, Moran, KA, and O'Connor, S. The effect of hip extension and Nordic hamstring exercise protocols on hamstring strength: A randomized controlled trial. J Strength Cond Res 35(10): 2682-2689, 2021-Lower and between-limb asymmetrical eccentric hamstring isokinetic strength may be associated with hamstring injuries, which mainly affect the biceps femoris. The 45° hip extension exercise (HEE) strengthens the hamstrings in the lengthened position where the biceps femoris experiences greatest loading during high-speed running. However, the effect of an HEE program on eccentric hamstring isokinetic strength has not been investigated or compared with the Nordic Hamstring Exercise (NHE) program. Twenty-four male, varsity, Gaelic footballers (22.4 ± 2.7 years; 182.1 ± 6.0 cm; 84.4 ± 7.9 kg) were randomly allocated to an HEE or NHE 4-week program. Isokinetic (60°·s-1) eccentric peak torque, functional hamstring-to-quadriceps ratio, and between-limb eccentric strength (absolute and percentage) asymmetries were recorded before and after intervention. Muscle soreness scores were reported after exercise using a visual analogue scale. A mixed between-within analysis of variance investigated group (HEE vs. NHE) by time (pre vs. post) interaction effects, and any main effects. An independent-samples t-test compared muscle soreness scores between the NHE and HEE groups. No interaction or group main effects were found. Main effects for time were observed on dominant and nondominant limbs for eccentric peak torque (p < 0.001, η2 = 0.21, p = 0.01, η2 = 0.51, respectively) and functional hamstring quadriceps ratio (p = 0.03, η2 = 0.59, p < 0.0001, η2 = 0.26, respectively). There were no main effects for time between-limb eccentric peak torque or percentage asymmetries (p = 0.41, η2 = 0.03, p = 0.20, η2 = 0.07, respectively), or differences in muscle soreness scores (p > 0.05). A 4-week HEE program increases eccentric hamstring isokinetic strength similar to a NHE program, which may be useful as part of a hamstring injury prevention program.

The hamstring/quadriceps ratio is an indicator of function in ACL-deficient, but not in ACL-reconstructed knees.

The purpose of this study was to investigate the isokinetic, eccentric and isometric hamstring/quadriceps (HQ) ratios in patients before and after ACL reconstruction (ACLR) using bone-patellar tendon grafts and to establish the relationships between HQ ratio and knee function. Forty-four patients (mean age of 26.6years) underwent isokinetic testing of quadriceps and hamstring muscles before and after ACLR and HQ ratios were calculated. Lysholm, IKDC and Cincinnati Scores were used to assess function. Isokinetic concentric and eccentric peak torque (Nm/kg) was measured at three different speeds: 60, 120, and 180°/s. Isometric strength was tested at 30° and 60° of knee flexion. For the isometric tests, the HQ ratio between the involved and non-involved limb was not different for the ACLD knee (p = 0.28) at 30° knee flexion, but significant at the 60° flexion angle (p = 0.02) and for the ACLR knees at 30° and 60° (p = 0.02). For the isokinetic tests, the ratio between involved and non-involved limb was significant for ACL-deficient knees at both 60 (p = 0.039) and 120°/s (p = 0.05). There were significant differences between limbs for all speeds in ACLR knees (p = 0.0003-0.01). For the eccentric tests, the HQ ratio between the involved and non-involved limbs was not significant for both the ACLD (p = 0.19) and ACLR knees (p = 0.29) at the speed of 60°/s. At 120 and 180°/s, there were significant differences between limbs for both the ACLD (p = 0.02) and ACLR knees (p = 0.003). Linear regression did not reveal significant relationships between Cincinnati, Lysholm, and IKDC scores and HQ ratios in the ACLD (R2 = 0.35, p = 0.58; R2 = 0.34, p = 0.63; R2 = 0.38, p = 0.49). In contrast, there were significant correlations between the Lysholm and IKDC scores and HQ ratios in the ACLR knees (R2 = 0.84, p = 0.002; R2 = 0.86, p = 0.001). The findings of this study suggest that the HQ ratio in ACLD patients was not a predictor, but an indicator of patient-perceived knee function following ACLR. Level IV, case series.

The Effect of 8-Week Nordic Hamstring Exercise on Hamstring Quadriceps Ratio and Hamstring Muscle Strength

The aim of the study is to investigate the effect of 8-week Nordic Hamstring (NH) exercise on hamstring/quadricepsratio (H/Q) and hamstring muscle strength. 22 amateur soccer players participated in the study. Soccer players weredivided into two groups: the control group (CG) (n = 11) who only practiced soccer training and the NordicHamstring exercise group (NHEG) (n = 11) who performed NH in addition to soccer training. The isokinetic kneemuscle strength of the soccer player was measured twice at the beginning of the study and after the 8 week NHexercise. An isokinetic dynamometer was used to determine isokinetic knee strengths of soccer players. Thedifference between pre-test and post-test results of isokinetic knee muscle strength of soccer players was determinedby Wilcoxon test. According to the results obtained, it was found that the H/Q ratio (at 180ºs-1 and 240ºs-1 angularvelocities) and hamstring muscle strength (60ºs-1, 180ºs-1 and 240ºs-1 angular velocities) increased statisticallysignificantly (p&lt;0.05). As a result, it can be stated that NH exercise is a very important factor in achieving thedesired level of H/Q ratio, which is an important factor in increasing sportive performance and thus decreasing therisk of injury as well as increasing hamstring muscle strength.

Functional sit-to-stands evoke greater neuromuscular activation than orthopaedic bed exercises in healthy older adults

OBJECTIVE: To compare EMG activity of the hip and thigh muscles during traditional static bed exercises and the sit-to-stand exercise in healthy older adults. METHODS: Twenty-four healthy, older adults (8 male; age 65±7 yrs) performed four static rehabilitation exercises: isometric contractions of the gluteal, abductor, inner quadriceps and quadriceps (ten, ~5 s submaximal contractions, with 60 rests), and the sit-to-stand test. Electromyographic (EMG) activity was recorded from the rectus femoris, vastus medialis, gluteus medius, biceps femoris and gluteus maximus, and root mean square-processed (RMS) in this observational preliminary study. Handgrip strength, 10 m walking speed and hamstring-quadriceps ratio represented participant characteristics. RESULTS: Hip and thigh muscles were activated differently between the isometric bed and sit-to-stand exercises. Greatest RMS activity was shown in the chair rising phase of the sit-to-stand exercise. No bed exercise exceeded the muscle RMS activity required to perform a sit-to-stand, and only for sit-to-stands were all muscles activated over 40% of maximal; the level required to stimulate muscle strength adaptation. CONCLUSIONS: Functional daily activities, such as sit-to-standing, produce greater muscle activity than static bed exercises in healthy older adults. Sit-to-stands should be included in exercise and rehabilitation programs for older adults, to evoke sufficient levels of neuromuscular activation for muscle strength adaptation.

The dynamic control ratio at the equilibrium point (DCRe): introducing relative and absolute reliability scores

ABSTRACTAnalytical methods to assess thigh muscle balance need to provide reliable data to allow meaningful interpretation. However, reproducibility of the dynamic control ratio at the equilibrium point has not been evaluated yet. Therefore, the aim of this study was to compare relative and absolute reliability indices of its angle and moment values with conventional and functional hamstring–quadriceps ratios. Furthermore, effects of familiarisation and angular velocity on reproducibility were analysed. A number of 33 male volunteers participated in 3 identical test sessions. Peak moments (PMs) were determined unilaterally during maximum concentric and eccentric knee flexion (prone) and extension (supine position) at 0.53, 1.57 and 2.62 rad · s–1. A repeated measure, ANOVA, confirmed systematic bias. Intra-class correlation coefficients and standard errors of measurement indicated relative and absolute reliability. Correlation coefficients were averaged over respective factors and tested for significant differences. All balance scores showed comparable low-to-moderate relative (<0.8–0.9) and good absolute reliability (<10%). Relative reproducibility of dynamic control equilibrium parameters augmented with increasing angular velocity, but not with familiarisation. At 2.62 rad · s–1, high (moment: 0.906) to moderate (angle: 0.833) relative reliability scores with accordingly high absolute indices (4.9% and 6.4%) became apparent. Thus, the dynamic control equilibrium is an equivalent method for the reliable assessment of thigh muscle balance.

Quadriceps And Hamstring Strength

Strength imbalances between the quadriceps and hamstring muscle groups, commonly measured with the hamstring to quadriceps ratio (HQR), are associated with performance decrements and injury risk. Many years of high intensity training completed by collegiate runners may contribute to such imbalances. Early identification of these imbalances may be useful for improving performance and reducing injury risk. PURPOSE:The purpose of this study was to determine if the number of years participating on an intercollegiate cross-country team influences hamstring strength, quadriceps strength, or HQR. METHODS: 10 female intercollegiate cross country runners with varying years of Division-1 experience (3-years, n=4; 2-years, n=3; 1-year, n=3) granted written consent and performed isokinetic testing of the dominant limb to determine maximal concentric strength of the quadriceps and hamstring muscle groups (3 reps; 120°/s; Biodex, Shirley, NY). The maximum torque value of all trials was selected and HQR was calculated for each participant. A linear regression was used to assess how collegiate experience influenced HQR, quadriceps strength and hamstring strength. RESULTS: Strength measures are reported in Table 1. A negative trend (R2=0.998) was observed in HQR. A positive trend (R2=0.747) was observed in quadriceps strength. No trend (R2=0.074) was observed in hamstring strength CONCLUSIONS:The findings suggest that athletes with more years of collegiate cross-country participation have a lower HQR. As there was no trend in hamstring strength, the difference in HQR may be attributed to the trend of greater quadriceps strength in athletes with more years on the team.

Lack of Correlation between Dynamic Balance and Hamstring-to-Quadriceps Ratio in Patients with Chronic Anterior Cruciate Ligament Tears.

PurposeThe purpose of this study was to evaluate the quadriceps and hamstring muscle strength and hamstring-to-quadriceps (HQ) ratio, as well as the relationships of these parameters with dynamic balance, in patients with anterior cruciate ligament (ACL) rupture.Materials and MethodsWe compared 25 patients diagnosed with chronic unilateral ACL tears and 25 age-matched healthy volunteers. The maximal torque of the quadriceps and hamstring and dynamic balance were measured.ResultsAlthough the isokinetic maximal peak torques were about 50% lower in the quadriceps (57%, p<0.001) and hamstring (56%, p=0.001) muscles in the chronic ACL tear group than in the control group, their HQ ratios were similar (56%±17% vs. 58%±6%, p=0.591). HQ ratio was significantly correlated with anterior-posterior stability index (r=-0.511, p=0.021) and overall stability index (r=-0.476, p=0.034) in control group, but these correlations were not observed in chronic ACL tear group.ConclusionsThigh muscle strength was about 50% lower in the chronic ACL tear group than in the control group, but the HQ ratio was similar. The dynamic balance of the knee was not influenced by thigh muscle strength but was influenced by HQ ratio in healthy young individuals. However, HQ ratio was not correlated with dynamic knee balance in chronic ACL tear patients.

Hamstrings strength imbalance in professional football (soccer) players in Australia.

The aim of this study was to describe the isokinetic thigh muscle strength profile of professional male football players in Australia. Concentric (60° and 240°·s(-1)) and eccentric (30° and 120°·s(-1)) hamstrings and quadriceps isokinetic strength was measured with a HUMAC NORM dynamometer. The primary variables were bilateral concentric and eccentric hamstring and quadriceps peak torque ratios, concentric hamstring-quadriceps peak torque ratios, and mixed ratios (eccentric hamstring 30°·s(-1) ÷ concentric quadriceps 240°·s(-1)). Hamstring strength imbalance was defined as deficits in any 2 of: bilateral concentric hamstring peak torque ratio <0.86, bilateral eccentric hamstring peak torque ratio <0.86, concentric hamstring-quadriceps ratio <0.47, and mixed ratio <0.80. Fifty-five strength tests involving 42 players were conducted. Ten players (24%) were identified as having hamstring strength imbalance. Athletes with strength imbalance had significantly reduced concentric and eccentric bilateral hamstring peak torque ratios at all angular velocities tested; and reduced eccentric quadriceps peak torque (30°·s(-1)) in their stance leg, compared with those without strength imbalance. Approximately, 1 in 4 players had preseason hamstring strength imbalance; and all strength deficits were observed in the stance leg. Concentric and eccentric hamstrings strength imbalance may impact in-season football performance and could have implications for the future risk of injury.

Significantly worse isokinetic hamstring–quadriceps ratio in patellofemoral compared to condylar defects 4 years after autologous chondrocyte implantation

Detailed biomechanical analysis including isokinetic muscle strength measurements after autologous chondrocyte implantation (ACI) are still rare, but might be of crucial importance for long-term outcomes. The present prospective study was performed to evaluate whether defect location had any influence on clinical and biomechanical outcomes 4years after ACI. Forty-four patients with full-thickness cartilage defects ICRS grade III B and C underwent ACI and were assigned to two groups, the femoral condyle group or the patellofemoral joint group. Clinical scores were gathered preoperatively and 6, 12 and 48months after implantation using the International Knee Documentation Committee (IKDC) score and the International Cartilage Repair Society (ICRS) form. Isokinetic strength measurements were performed 48months postoperatively comparing healthy and operated knee joint of each patient. Clinical scores (ICRS, IKDC) showed continuous significant (p<0.05) improvement over the study period for both groups. Isokinetic muscle strength measurements showed significantly reduced maximum strength capacities for the operated knee joint compared to the healthy knee in both groups (p<0.05). Hamstring-quadriceps ratios of the operated extremity revealed a significant change in physiological muscle balancing (ratios >1.0) based on significantly impaired extensor muscle strength in the patellofemoral joint group. All patients showed significant strength deficits on the operated extremity 4years after ACI. Furthermore, the patellofemoral compartment in particular showed significantly worse hamstring-quadriceps ratios compared to condylar defects. Consequently, more efforts should be made to restore muscular strength especially of the quadriceps and the rehabilitation protocol should be adjusted accordingly. II.