Effects of hip flexion angle on surface electromyographic activity of the biceps femoris and semitendinosus during isokinetic knee flexion

The purpose of this study was to compare the hamstring to quadriceps ratio (H:Q) obtained from three different hip flexion angles. Seventy-three young athletes performed maximum isokinetic concentric and eccentric knee extension and flexion efforts at 60 °·s−1 and 240 °·s−1 from hip flexion angles of 90°, 60°, and 120°. The conventional (concentric to concentric), functional (eccentric to concentric) and mixed (eccentric at 30 °·s−1 to concentric torque at 240 °·s−1) H: Q torque ratios and the electromyographic activity from the rectus femoris and biceps femoris were analyzed. The conventional H:Q ratios and the functional H:Q ratios at 60 °·s−1 did not significantly differ between the three testing positions (p > 0.05). In contrast, testing from the 90° hip flexion angle showed a greater functional torque ratio at 240 °·s−1 and a mixed H:Q torque ratio compared with the other two positions (p < 0.05). The hip flexion angle did not influence the recorded muscle activation signals (p > 0.05). For the range of hip flexion angles tested, routine isokinetic assessment of conventional H:Q ratio and functional H:Q ratio at slow speed is not angle-dependent. Should assessment of the functional H:Q ratio at fast angular velocity or the mixed ratio is required, then selection of hip flexion angle is important.

Download Full-text

Comparison of Muscle Activation and Kinematics in 6-RM Squatting With Low and High Barbell Placement

Journal of Human Kinetics ◽

10.2478/hukin-2020-0021 ◽

2020 ◽

Vol 74 (1) ◽

pp. 131-142

Author(s):

Roland van den Tillaar ◽

Eric Helms

Keyword(s):

Knee Flexion ◽

Average Velocity ◽

Muscle Activation ◽

Joint Kinematics ◽

Flexion Angle ◽

Knee Flexion Angle ◽

Muscular Development ◽

Hip Flexion ◽

Maximal Capacity ◽

Over Time

Abstract The aim of this study was to compare 6-RM muscle activation and kinematics in back squats with low and high barbell placements. Twelve resistance-trained males (23.5 ± 2.6 years, 86.8 ± 21.3 kg, 1.81 ± 0.08 m) with a minimum of 2 years of squatting experience performed a 6-RM using high and low barbell placements while muscle activation of eight muscles and joint kinematics were measured. During high barbell placement squats, lifting time was longer, with lower average velocity than low barbell placement. This was accompanied by a lesser knee flexion angle at the lowest point of the squat, and larger hip flexion angles during high, compared to low barbell squats. Furthermore, peak angular ankle, knee and hip velocities in the descending phase developed differently between conditions. No significant differences in muscle activation were found between conditions. Thus, our data suggests gross muscular adaptations between barbell placements may be similar over time, and therefore, from a muscular development standpoint, both squat styles are valid. Furthermore, unlike the low barbell placement, fatigue may manifest earlier itself in the high barbell squats during 6-RMs as sets progress toward a lifter’s maximal capacity, altering kinematics, especially in the last repetition.

Download Full-text

Effects of Hip Flexion on Knee Extension and Flexion Isokinetic Angle-Specific Torques and HQ-Ratios

Sports Medicine - Open ◽

10.1186/s40798-021-00330-w ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Christian Baumgart ◽

Eduard Kurz ◽

Jürgen Freiwald ◽

Matthias Wilhelm Hoppe

Keyword(s):

Hip Joint ◽

Knee Flexion ◽

Daily Life ◽

Knee Extension ◽

Flexion Angle ◽

Strength Testing ◽

Knee Strength ◽

Sporting Activities ◽

Torque Values ◽

Hip Flexion

Abstract Background and Methods During isokinetic knee strength testing, the knee flexion angles that correspond to the measured torque values are rarely considered. Additionally, the hip flexion angle during seated testing diverges from that in the majority of daily life and sporting activities. Limited information concerning the influence of hip angle, muscle contraction mode, and velocity on the isokinetic knee strength over the entire range of motion (ROM) is available. Twenty recreational athletes (10 females, 10 males; 23.3 ± 3.2 years; 72.1 ± 16.5 kg; 1.78 ± 0.07 m) were tested for isokinetic knee flexion and extension at 10° and 90° hip flexion with the following conditions: (i) concentric at 60°/s, (ii) concentric at 180°/s, and (iii) eccentric at 60°/s. The effects of hip angle, contraction mode, and velocity on angle-specific torques and HQ-ratios as well as conventional parameters (peak torques, angles at peak torque, and HQ-ratios) were analyzed using statistical parametric mapping and parametric ANOVAs, respectively. Results Generally, the angle-specific and conventional torques and HQ-ratios were lower in the extended hip compared to a flexed hip joint. Thereby, in comparison to the knee extension, the torque values decreased to a greater extent during knee flexion but not consistent over the entire ROM. The torque values were greater at the lower velocity and eccentric mode, but the influence of the velocity and contraction mode were lower at shorter and greater muscle lengths, respectively. Conclusions Isokinetic knee strength is influenced by the hip flexion angle. Therefore, a seated position during testing and training is questionable, because the hip joint is rarely flexed at 90° during daily life and sporting activities. Maximum knee strength is lower in supine position, which should be considered for training and testing. The angle-specific effects cannot be mirrored by the conventional parameters. Therefore, angle-specific analyses are recommended to obtain supplemental information and consequently to improve knee strength testing.

Download Full-text

Ergonomic Assessment of Exiting Automobiles

Proceedings of the Human Factors and Ergonomics Society Annual Meeting ◽

10.1177/154193129303700501 ◽

1993 ◽

Vol 37 (5) ◽

pp. 401-405 ◽

Cited By ~ 4

Author(s):

Josef Loczi

Keyword(s):

Kinetic Parameters ◽

Knee Flexion ◽

Flexion Angle ◽

Regression Equations ◽

Seat Height ◽

Seat Position ◽

Student Subjects ◽

Screen System ◽

Hip Flexion ◽

High Degree

The purpose of this study was to investigate the effects of changing seat heights (51 cm, 59 cm, 67 cm), door heights (122 cm, 138 cm, 154 cm) and seat positions (27 cm and 35 cm) in automobiles on kinematic parameters (trunk rotation, trunk angle, hip flexion angle and knee flexion angle) and kinetic parameters (lumbar moment, hip moment and knee moment) while exiting automobiles. Twelve student subjects were videotaped with 2 video cameras synchronized into a split screen system. Manipulating seat height, door height and seat position resulted in 18 different testing conditions. Real time animated graphics, as well as 3-D kinematic and kinetic parameters of the movement were obtained via a video image computer capture system and newly developed 3-D digitizing software. It was determined from the study that: a) Seat and door height had significant effects on kinematic and kinetic parameters, but not seat position, b) As seat and door height increased maximum values for kinematic and kinetic parameters decreased, c) Hip and knee flexion angles seem to be an acceptable subset of variables that can be used to evaluate ease of exit, d) It seems there exists a “critical seat height” at which an equilibrium exists between the demands of maintaining balance and stability and the need to reduce stress on the lower back when exiting an automobile. e) The behavior of hip and knee flexion angles can be predicted with a high degree of confidence via regression equations.

Download Full-text

Different squatting positions after total knee arthroplasty: a video-based observational study

10.21203/rs.3.rs-18057/v1 ◽

2020 ◽

Author(s):

Jing-yang Sun ◽

Guo-qiang Zhang ◽

Tie-jian Li ◽

Jun-min Shen ◽

Yin-qiao Du ◽

...

Keyword(s):

Total Knee Arthroplasty ◽

Knee Arthroplasty ◽

Knee Flexion ◽

Ankle Dorsiflexion ◽

Flexion Angle ◽

Knee Flexion Angle ◽

Total Knee ◽

The Mean ◽

Hip Flexion ◽

Deep Squat

Abstract Aims There are no methods to assess patient’s squatting ability after TKA (total knee arthroplasty), this study aimed to evaluate the different squatting position of a series of patients who underwent primary TKA.Methods From May 2018 to October 2019, we retrospectively reviewed 154 videos recording the squattin-related motions of patients after TKA. Among the included patients, 119 were women and 35 were men. Their mean age at the index surgery was 61.4 years (range, 30 to 77). The median follow-up was 12 months (range, 6 to 156). We classified those squatting-related motions into three major variations according to squatting depth: half squat, parallel squat, and deep squat. The angle of hip flexion, knee flexion and ankle dorsiflexion were measured in the screenshots captured from the videos at the moment of squatting nadir.Results A total of 26 patients were classified as half squat, 75 as parallel squat, and 53 as deep squat. The angle of hip flexion, knee flexion and ankle dorsiflexion all differed significantly among the three squatting positions (p<0.001). In the parallel squat group, the mean knee flexion angle(°) was 116.5 (SD, 8.1; range, 97 to 137). In the deep squat group, the mean knee flexion angle(°) was 132.5 (SD, 9.3; range, 116 to 158). Among the three squatting positions, deep squat showed the highest hip, knee and ankle flexion angle. And the next was parallel squat.Conclusion Our squatting position classification offers a pragmatic approach to evaluating patient’s squatting ability after TKA. However, the relation between squatting position and daily activity requires further investigation.

Download Full-text

Moderate Associations of Muscle Elasticity of the Hamstring with Hip Joint Flexibility

International Journal of Sports Medicine ◽

10.1055/a-0981-7282 ◽

2019 ◽

Vol 40 (11) ◽

pp. 717-724 ◽

Cited By ~ 3

Author(s):

Naokazu Miyamoto ◽

Kosuke Hirata

Keyword(s):

Shear Modulus ◽

Hip Joint ◽

Joint Stiffness ◽

Shear Wave Elastography ◽

Biceps Femoris ◽

Flexion Angle ◽

Shear Moduli ◽

Muscle Elasticity ◽

Young Males ◽

Hip Flexion

AbstractThe main purpose of the present study was to identify whether and to what extent the individual differences in range of motion and stiffness of the hip joint can account for that in muscle elasticity of the hamstring. Hip extension torque and shear moduli (a measure of elasticity) of the biceps femoris, semitendinosus, and semimembranosus were assessed in 21 young males during unilateral passive hip flexion in the knee-extended position from the anatomical position to the individual’s maximal hip flexion angle. Muscle shear modulus was quantified by using ultrasound shear wave elastography. The maximal hip flexion angle correlated negatively with the shear modulus of each muscle (−0.750 ≤ r ≤ −0.612). The joint stiffness correlated positively with the shear modulus of each muscle (0.711 ≤ r ≤ 0.747). These findings suggest that hip flexion ROM and joint stiffness can reflect significantly but only moderately the muscle elasticity of the hamstring.

Download Full-text

Influence of Hip-Flexion Angle on Hamstrings Isokinetic Activity in Sprinters

Journal of Athletic Training ◽

10.4085/1062-6050-47.4.04 ◽

2012 ◽

Vol 47 (4) ◽

pp. 390-395 ◽

Cited By ~ 23

Author(s):

Kenny Guex ◽

Boris Gojanovic ◽

Grégoire P. Millet

Keyword(s):

Root Mean Square ◽

Knee Flexion ◽

National Level ◽

Peak Torque ◽

Muscular Contraction ◽

Flexion Angle ◽

Mean Square ◽

Resistance Training Program ◽

The Right ◽

Hip Flexion

Context: Hamstrings strains are common and debilitating injuries in many sports. Most hamstrings exercises are performed at an inadequately low hip-flexion angle because this angle surpasses 70° at the end of the sprinting leg's swing phase, when most injuries occur. Objective: To evaluate the influence of various hip-flexion angles on peak torques of knee flexors in isometric, concentric, and eccentric contractions and on the hamstrings-to-quadriceps ratio. Design: Descriptive laboratory study. Setting: Research laboratory. Patients and Other Participants Ten national-level sprinters (5 men, 5 women; age = 21.2 ± 3.6 years, height = 175 ± 6 cm, mass = 63.8 ± 9.9 kg). Intervention(s): For each hip position (0°, 30°, 60°, and 90° of flexion), participants used the right leg to perform (1) 5 seconds of maximal isometric hamstrings contraction at 45° of knee flexion, (2) 5 maximal concentric knee flexion-extensions at 60° per second, (3) 5 maximal eccentric knee flexion-extensions at 60° per second, and (4) 5 maximal eccentric knee flexion-extensions at 150° per second. Main Outcome Measure(s): Hamstrings and quadriceps peak torque, hamstrings-to-quadriceps ratio, lateral and medial hamstrings root mean square. Results: We found no difference in quadriceps peak torque for any condition across all hip-flexion angles, whereas hamstrings peak torque was lower at 0° of hip flexion than at any other angle (P < .001) and greater at 90° of hip flexion than at 30° and 60° (P < .05), especially in eccentric conditions. As hip flexion increased, the hamstrings-to-quadriceps ratio increased. No difference in lateral or medial hamstrings root mean square was found for any condition across all hip-flexion angles (P > .05). Conclusions: Hip-flexion angle influenced hamstrings peak torque in all muscular contraction types; as hip flexion increased, hamstrings peak torque increased. Researchers should investigate further whether an eccentric resistance training program at sprint-specific hip-flexion angles (70° to 80°) could help prevent hamstrings injuries in sprinters. Moreover, hamstrings-to-quadriceps ratio assessment should be standardized at 80° of hip flexion.

Download Full-text

Biceps Femoris Muscle is Activated by Performing Nordic Hamstring Exercise at a Shallow Knee Flexion Angle

Journal of Sports Science and Medicine ◽

10.52082/jssm.2021.275 ◽

2021 ◽

pp. 275-283

Author(s):

Norikazu Hirose ◽

Masaaki Tsuruike ◽

Ayako Higashihara

Keyword(s):

Knee Flexion ◽

Gluteus Maximus ◽

Biceps Femoris ◽

Flexion Angle ◽

Hamstring Injury ◽

Emg Activity ◽

Knee Flexion Angle ◽

Male Athletes ◽

Biceps Femoris Muscle ◽

Long Head

The semitendinosus (ST) muscle is primarily used during Nordic hamstring exercise (NHE), which is often prescribed for preventing hamstring injury, though the biceps femoris long head (BFlh) muscle that is more susceptible to injuries. Thus, this study aimed to identify the modulation of BFlh muscle activity with different knee flexion angles during NHE using an inclined platform. Fourteen male athletes performed NHE and maintained their position at maximum inclination (NH). Subjects also performed isometric NHE using a platform inclined to 50° (ICL) and 40° (ICH), and the knee flexion angle was controlled to 50° and 30°. The electromyography (EMG) activity of the BFlh, ST, semimembranosus, gluteus maximus, elector spinae, and rectus abdominus muscles was determined during each exercise. The EMG of the ST was higher than that of the BFlh during NHE and the highest of all muscles in all exercises (p < 0.05). Moreover, the activity of the BFlh tended to be higher than that of the ST for ICH than for ICL, regardless of the knee joint angle. The activity of the BFlh becomes equivalent to that of the ST during NHE at a knee flexion angle of less than 50°. These results indicate that performing NHE at a shallow knee flexion angle will enhance the activity of the BFlh muscle.

Download Full-text

Single-Leg Landings Following a Volleyball Spike May Increase the Risk of Anterior Cruciate Ligament Injury More Than Landing on Both-Legs

Applied Sciences ◽

10.3390/app11010130 ◽

2020 ◽

Vol 11 (1) ◽

pp. 130

Author(s):

Datao Xu ◽

Xinyan Jiang ◽

Xuanzhen Cen ◽

Julien S. Baker ◽

Yaodong Gu

Keyword(s):

Anterior Cruciate Ligament ◽

Knee Flexion ◽

Sagittal Plane ◽

Cruciate Ligament ◽

Flexion Angle ◽

Ligament Injury ◽

Time Range ◽

Acl Injuries ◽

Volleyball Players ◽

Anterior Cruciate

Volleyball players often land on a single leg following a spike shot due to a shift in the center of gravity and loss of balance. Landing on a single leg following a spike may increase the probability of non-contact anterior cruciate ligament (ACL) injuries. The purpose of this study was to compare and analyze the kinematics and kinetics differences during the landing phase of volleyball players using a single leg (SL) and double-leg landing (DL) following a spike shot. The data for vertical ground reaction forces (VGRF) and sagittal plane were collected. SPM analysis revealed that SL depicted a smaller knee flexion angle (about 13.8°) and hip flexion angle (about 10.8°) during the whole landing phase, a greater knee and hip power during the 16.83–20.45% (p = 0.006) and 13.01–16.26% (p = 0.008) landing phase, a greater ankle plantarflexion angle and moment during the 0–41.07% (p < 0.001) and 2.76–79.45% (p < 0.001) landing phase, a greater VGRF during the 5.87–8.25% (p = 0.029), 19.75–24.14% (p = 0.003) landing phase when compared to DL. Most of these differences fall within the time range of ACL injury (30–50 milliseconds after landing). To reduce non-contact ACL injuries, a landing strategy of consciously increasing the hip and knee flexion, and plantarflexion of the ankle should be considered by volleyball players.

Download Full-text