Effect of repetitive peripheral magnetic stimulation of the common fibular nerve on the soleus muscle Hoffmann reflex.

[Purpose] This study aimed to investigate the effects of repetitive peripheral magnetic stimulation of the common fibular nerve on the modification of neural circuit function as measured through the soleus muscle Hoffmann reflex. [Participants and Methods] Twenty-four healthy adult males were randomly and equally divided into the magnetic stimulation (experimental) and control groups. The Hoffmann reflex of the soleus muscle was analyzed before and after 10 min of repetitive peripheral magnetic stimulation for the experimental group and before and after 10 min of rest for the control group. The averages of the values for the maximum amplitude and latency of the Hoffman reflex across twenty repetitions were recorded and compared. [Results] The Hoffmann reflex amplitude decreased following stimulation in the experimental group, and significant variations were observed between the experimental and control groups. [Conclusion] The change in the Hoffmann reflex amplitude may have been caused by the magnetic stimulation to I-a sensory fibers on the common fibular nerve, suggesting that magnetic stimulation induces reciprocal inhibition of motor neurons through synapses in the spinal cord.

Developmental stage and lower quadriceps flexibilities and decreased gastrocnemius flexibilities are predictive risk factors for developing Osgood-Schlatter disease in adolescent male soccer players.

PURPOSE: This study aimed to elucidate the influential predictive risk factors of Osgood-Schlatter disease (OSD) on the support (non-kicking) leg among adolescent soccer players considering peak height velocity (PHV) age and investigate the cut-off values of the predictive variables. METHODS: A cohort of 302 Japanese adolescent male soccer players aged 12-13 years were followed over 6 months. All players underwent physical examination, tibial tubercle ultrasonography, anthropometric and whole-body composition measurements, and muscle flexibility test of the support leg at the baseline. The developmental stage was evaluated from the PHV age. The OSD of the support leg was diagnosed 6 months later; players were divided into the OSD and control (CON) groups. The predictive risk factors were analyzed by multivariate logistic regression analysis. RESULTS: There were 42 players who had developed OSD at baseline and they were excluded from the study. Among the 209 players, 43 and 166 belonged to the OSD and CON groups, respectively. The predictive risk factors of OSD development were PHV age ± 6 months at baseline (p = 0.046), apophyseal stage of tibial tuberosity maturity at baseline (p < 0.001), quadriceps flexibility ≥ 35° at baseline (p = 0.017), and decrease in gastrocnemius flexibility in 6 months (p = 0.009). CONCLUSION: PHV age ± 6 months at baseline, apophyseal stage of the tibial tuberosity at baseline, quadriceps flexibility ≥ 35° at baseline, and decrease in gastrocnemius flexibility in 6 months are predictive risk factors of OSD development in the support leg among adolescent male soccer players. It is crucial to know the PHV age of each player, and not only the flexibility of quadriceps muscle but also the gastrocnemius should be monitored to predict OSD. LEVEL OF EVIDENCE: II.

Characteristics of the Kicking Motion in Adolescent Male Soccer Players Who Develop Osgood-Schlatter Disease: A Prospective Study.

Background: Osgood-Schlatter disease (OSD) is an apophysitis of the tibial tubercle caused by repeated traction of the patellar tendon during adolescence. Although OSD is associated more with sports such as soccer, it remains unclear whether the kicking motion itself is related to OSD onset. Purpose: To prospectively evaluate the kicking motion in adolescent soccer players who later developed OSD. Study Design: Case-control study. Methods: The authors observed 47 Japanese adolescent male soccer players (mean age, 12 years) over 6 months in 2018-2019; none of the participants had OSD at study onset. The players underwent tibial tubercle ultrasound at baseline, and their kicking motion was evaluated using 3-dimensional (3D) motion analysis with 65 reflective markers. The 3D angle of the lumbar spine, thorax, and pelvis and the angular velocity of the hips, knees, and ankles were calculated for the support leg. The kicking motion was divided into 8 phases, and ball speed, kicking time, and positions of the support (nonkicking) leg and center of mass (COM) from the ball were calculated for each phase. Six months later, the players underwent another ultrasound and were divided into 2 groups: those diagnosed with OSD in the support leg (OSD group) and those without OSD (normal [NRL] group). All factors calculated using the kicking motion analysis at the baseline were compared between groups. Results: There were 19 players in the OSD group and 28 players in the NRL group. Anthropometric measurements, ball speed, and kicking time were similar between the 2 groups. The forward translation of the COM and the support leg, the flexion angle of the thorax, and the rotation angle of the pelvis before impact with the ball were all significantly smaller in the OSD group than in the NRL group (P < .05). Moreover, the knee extension angular velocity of the support leg was significantly larger in the OSD group (P < .05) at ball impact. Conclusion: A kicking motion with small COM translation, small thoracic flexion, and small pelvic rotation before ball impact, as well as large knee extension angular velocity of the support leg at ball impact, may be associated with OSD onset.

Is Increased Kicking Leg Iliopsoas Muscle Tightness a Predictive Factor for Developing Spondylolysis in Adolescent Male Soccer Players?

OBJECTIVE: To identify predictive risk factors of lumbar stress (LS) fracture developing from an asymptomatic stress reaction of the pedicle among adolescent male soccer players. DESIGN: Prospective cohort study. SETTING: Amateur Japanese adolescent male soccer team. PARTICIPANTS: Japanese adolescent male soccer players (n = 195) aged 12 to 13 years. ASSESSMENT OF RISK FACTORS INDEPENDENT VARIABLES: Height, body weight, body mass index, muscle tightness of both lower extremities (iliopsoas, hamstrings, and quadriceps), lumbar bone mineral content, developmental age, and lumbar lordosis angle were measured as baseline measurements. MAIN OUTCOME MEASURES DEPENDENT VARIABLE: Players who were diagnosed with an asymptomatic stress reaction of the lumbar spine pedicle at baseline were followed; extension-based lumbar pain was defined 1 year after the baseline. The players were assigned to the LS fracture or control (CON) group at follow-up. RESULTS: At baseline, 40 boys were diagnosed with an asymptomatic stress reaction of the lumbar spine pedicle. The difference in muscle tightness between the kicking leg and supporting leg was significantly different (P = 0.012) between the LS (n = 16) and CON (n = 22) groups. Increase in iliopsoas muscle tightness in the kicking leg was a predictive risk factor of developing extension-based lumbar pain after adjusting for developmental age and body mass index (odds ratio, 1.54; 95% confidence interval, 1.05-2.27). CONCLUSIONS: Development of extension-based lumbar pain from an asymptomatic stress reaction of the pedicle among adolescent male soccer players was associated with increased iliopsoas muscle tightness of the kicking leg relative to that of the supporting leg.

Factors Associated with Ball Velocity and Low Back Pain During Kicking in Adolescent Soccer Players.

PURPOSE: The factors associated with low back pain (LBP) and the relationship between LBP and ball velocity during kicking motion of adolescent soccer players remain largely unknown. This study aims to clarify the relationship between increasing ball velocity and LBP in adolescent soccer players. PARTICIPANTS AND METHODS: Adolescent soccer players were divided into two groups according to the presence and absence of LBP (LBP group, n=38 and NBP (no back pain) group, n=29, respectively). Real-time kick motion was measured using a three-dimensional motion analysis system and the angle of the lumbar spine, hip, and center of mass (COM) were calculated. Regression analysis was used to identify factors associated with ball velocity and LBP. In addition, Pearson's correlation coefficients were determined between the angle of the lumbar spine and hip, and ball velocity and position of COM in the extracted phase from regression analysis. RESULTS: The major factor associated with increasing ball velocity was the rotation angle of both hips (Adjusted R2=0.244) and vertical position of COM during kicking (Adjusted R2=0.262). Furthermore, the factors associated with LBP were the flexion angle of kick-side hip (OR=1.126) and abduction angle of both hips (kick-side OR=1.124; support-side OR=0.872). The factors for ball velocity and LBP were related to the maximum hip extension phase. In the hip extension phase of kicking, compared with the NBP group, the LBP group showed lesser extension and external rotation of the kick-side hip angle. In the hip flexion phase of kicking, the ball velocity was correlated with vertical (r=0.56)/anterior (r=0.46) position of COM in the NBP group. CONCLUSION: To compensate for this restricted hip motion, the LBP group could extend and rotate their lumbar spine, which may likely cause stress to this region.

Changes in thoracic and lumbar spinal motions during running in a female with scoliosis.

[Purpose] The aim of this study was to analyze changes in thoracic and lumbar spinal motions during running in a female athlete with scoliosis. [Participant and Methods] A female with scoliosis who was a member of a college track team was recruited for this study. On 1.5-T magnetic resonance imaging, angles between bodies of adjacent vertebrae in the frontal plane were calculated. We measured real-time spine movement while running using a three-dimensional motion analysis system, wherein the running speed was altered (6, 9, and 12 km/h). [Results] We observed a Cobb angle of 29.0° and the right convex curvature of the thoracolumbar spine on magnetic resonance imaging. As the running speed increased, during the right stance phase, the participant increased the lateral bending angle of the thoracic spine to the left and the lumbar spine to the right. However, during the left stance phase, the runner bent the thoracic spine to the right and the lumbar spine to the left, indicating a decreased convex curvature of the spine. [Conclusion] As the running speed increased, the convex curvature of the spine was corrected during the left stance phase but was uncorrected during the right stance phase.

Changes in hip and spine movement with increasing running speed.

[Purpose] We aimed to clarify and compare the changes in thoracic and lumbar spine motion and to elucidate the relationship between hip and lumbar spine motion during running. [Participants and Methods] Seven healthy females were recruited in this study. Hip and spine movement were measured using a 3D motion analysis system when running at 6, 9, and 12 km/h. One-way analysis of variance was used to compare the changes in hip joint and spine angles during running. Correlation coefficient analysis was used to determine the relationship between the hip and lumbar spine angles at right and left toe-offs. [Results] As the running speed increased, the rotation angles of the thoracic and lumbar spine and the extension angles of the lumbar spine and hip joint significantly increased in the late stance phase. Significant positive relationships were observed between hip flexion and lumbar spine extension angles at toe-off when running at 6 and 9 km/h but not when running at 12 km/h. [Conclusion] To increase the running speed, participants increased the rotation angle of spine and the extension angles of the hip joint and lumbar spine during the stance phase. Participants extended the lumbar spine to compensate for the restricted hip motion at toe-off, which could cause stress to the lumbar spine.

COMPARISON OF LUMBOPELVIC RHYTHM AMONG ADOLESCENT SOCCER PLAYERS WITH AND WITHOUT LOW BACK PAIN.

BACKGROUND: Hip-spine incoordination can cause low back pain (LBP) in adolescents. Hip-spine coordination, including the lumbopelvic rhythm (LPR) and the lumbar-hip ratio (LHR), can be used to assess lower limb and spine function. However, there are no reports of the values of LPR or LHR in adolescent soccer players with and without LBP. PURPOSE: The purpose of this study was to clarify the effect of LBP on LPR and LHR during trunk extension among adolescent soccer players. STUDY DESIGN: A cross-sectional observational study. METHODS: One hundred and nine adolescent soccer players were recruited and divided into two groups, one with and one without LBP. Using three-dimensional motion analysis, participants range of motion (ROM) of the lumbar spine (LS) and hip during trunk and hip extension was measured to calculate the LPR and LHR. Paired, two-tailed t-tests were used to compare the LS and hip ROM between the non-LBP and LBP groups, two-way repeated measures analysis of variance was used to compare time with the non-LBP and LBP groups for LHR, and linear prediction was used to describe the LPR. RESULTS: The maximum LS ROM in the LBP group was significantly less than that in the non-LBP group by 6.6 ° (p = .005). There was no difference in the maximum hip ROM between the groups (p = .376). The LHR did not change during trunk extension (F [4, 428] = 1.840, p = .120), the mean LHR was 4.6 in the non-LBP group and 3.7 in the LBP group, and there was no difference between the groups (p = .320). The linear function of the LPR indicated, that when the hip joint was extended by 1 °, the LS extended by 3.2 ° in the non-LBP group (R2 = .997, p < .001) and 2.8 ° in the LBP group (R2 = .999, p < .001). CONCLUSION: LBP inhibited lumbar motion relative to hip extension as LPR was smaller in the LBP group than in the non-LBP group. However, there was no difference between the groups in LHR because inter-individual variability affected the LHR. LEVEL OF EVIDENCE: 3b.

Difference in kick motion of adolescent soccer players in presence and absence of low back pain.

Many adolescent soccer players experience low back pain (LBP). However, there are no reports studying the kick motion of adolescent soccer players experiencing LBP. This study aimed to clarify the kick motion of adolescent soccer players in the presence and absence of LBP. We recruited 42 adolescent soccer players and divided them into two groups according to the presence of LBP (LBP group, n=22) and absence of LBP (NBP group, n=20). We measured real-time kick motion using a three-dimensional motion analysis system. We placed 65 spherical markers on each anatomical landmark and calculated the angle of the lumbar spine, center of mass (COM) of the whole body, and displacement of the support foot. We used an unpaired t-test to compare the data between the groups. Compared with the NBP group, the LBP group showed a lateral shift in COM, which increased the duration of kick motion. The presence of LBP affected the posterior positioning of the support foot and restricted the player's lumbar spine from bending laterally. A lateral shift in COM and larger rotation of the lumbar spine could stress the lumbar spine during kick motion. Therefore, coaches and athletic trainers should pay attention to soccer players' lumbar spine rotation and the COM shift during kick motion. This would be important for preventing LBP in adolescent soccer players.

Changes in lumbopelvic rhythm during trunk extension in adolescent soccer players.

Many adolescent athletes experience low back pain (LBP). Its causative factors include lower limb muscle tightness and hip-spine incoordination. Hip-spine coordination [or lumbopelvic rhythm, LPR] can be used to assess lower-limb and spine functions. We assessed the presence/absence of LBP in adolescent soccer players before and after a six-month period and divided them into four groups: no LBP both before and after the period (NBP group); LBP before but not after (PN group); LBP after but not before (NP group); and LBP both before and after (LBP group). We used a 3D motion analysis system during trunk extension to measure the lumbar spine and hip ranges of motion (ROMs). On comparing the results obtained before and after the six-month period, lumbar spine ROM decreased in the NP group, hip ROM increased in the LBP group. From before to after the period, the linear prediction indicated that, when the hip extends by 1°, the lumbar spine extends by 3.5°-3.2° for the PN group and by 3.4°-2.8° for the NP group. The NP group extended their lumbar spine excessively compared with the hip before the period, which could cause LBP, but decreased the extension after the period. Lumbar extension relative to hip extension decreased in the PN group, which could decrease excessive load on the lumbar spine and eliminate LBP. These findings suggest that to prevent LBP in adolescent soccer players, it is important to restrict lumbar spine extension relative to hip extension.

Three-dimensional motion analysis of lumbopelvic rhythm during lateral trunk bending.

[Purpose] To examine the variations in the lumbopelvic rhythm and lumbar-hip ratio in the frontal plane. [Subjects and Methods] Markers were placed on the T10 and T12 spinous processes, bilateral paravertebral muscles at the T11 level, the pelvis, and the femur. Lumbar spine and hip angles were measured during lateral trunk bending using three-dimensional motion analysis. Data from the trunk lateral bending movement were categorized into descending (start of hip movement to when the hip angle reached its maximum value) and ascending (from the maximum hip angle to the end of movement) phases. The lumbar-hip ratio was calculated as the ratio of the lumbar spine angle to the hip angle. [Results] The lumbar-hip ratio decreased from 5.9 to 3.6 in the descending phase, indicating lumbar spinal movement was less than hip movement. In the ascending phase, the lumbar-hip ratio was reversed. The lumbopelvic rhythm was better expressed by a cubic or quadratic function rather than a linear function. These functions indicate that when the hip inclines by 1° that the lumbar spine bends laterally by 2.4°. [Conclusion] The lumbopelvic rhythm and lumbar-hip ratio indicate lumbar lateral bending instead of a limitation of hip inclination.

Three-Dimensional Motion Analysis of Lumbopelvic Rhythm During Trunk Extension.

Hip-spine coordination, known as the lumbopelvic rhythm, can be expressed as the lumbar-hip ratio. The lumbopelvic rhythm and lumbar-hip ratio can be used to assess lower limb function. We clarified the lumbopelvic rhythm and lumbar-hip ratio during trunk extension. We established a novel set of marker positions for three-dimensional motion analysis to assess the lumbar spinal angle. The original markers were placed on both paravertebral muscle groups at the 11th thoracic spinous process level, the 10th and 12th thoracic spinous processes, and the pelvis. We measured angle data during trunk extension using three-dimensional motion analysis, and the data for eight healthy male subjects were categorized into backward and forward phases. The lumbar-hip ratio increased significantly from 1.2 to 1.9 (mean, 1.6) in the backward phase, indicating considerable movement of the lumbar spine compared with hip movement in the latter phase. In the forward phase, the ratio decreased significantly from 1.9 to 0.5 (mean, 1.5). After completion of 80% of the forward phase, the lumbar-hip ratio decreased to <1.0. The lumbopelvic rhythm for trunk extension was better expressed by a cubic or quadratic function than a linear function. According to a linear function, when the hip extends by 1°, lumbar spine extends by 1.9°. Therefore, lumbar spinal movement was greater than hip movement in the sagittal plane. The implication of the curved line would indicate lumbar extension instead of the limitation of hip extension.

Changes in serum creatine kinase, leg muscle tightness, and delayed onset muscle soreness after a full marathon race.

BACKGROUND: Muscle tightness (MT) is believed to be an important cause of injury for runners. This study evaluated the change of serum creatine kinase (CK), MT in the leg muscles, and delayed onset muscle soreness after running. METHODS: We evaluated 11 college students who completed a full marathon race. Participants completed a questionnaire on the right quadriceps muscle soreness. The CK activity and MT (iliopsoas, rectus femoris, hamstrings, gastrocnemius, and soleus muscles) were measured. The time points for CK measurements were before; immediately after; and at 1, 2, and 5 days after the race. The time points for MT measurements were the same as for CK except MT was not measured one day after the race. The time points for muscle soreness analysis were before the race and then every morning and night for 5 days after the race. RESULTS: Long-distance running led to significant increases in CK, MT, and muscle soreness. The CK levels peaked day 1 after the race. MT of iliopsoas peaked on day 5; of rectus femoris immediately after the race; and of hamstrings, gastrocnemius, and soleus on day 2. muscle soreness peaked at night on day 1. MT did not decrease to the pre-race levels on day 5. There were no significant changes but CK tended to correlate with the peak of MT of the rectus femoris (r=0.55, P=0.082) and hamstrings (r=0.57, P=0.065). CONCLUSIONS: Long-distance running may cause muscle fiber microdamage that may consequently increase CK, MT, and muscle soreness.

Clarification of functional differences between the hallux and lesser toes during the single leg stance: immediate effects of conditioning contraction of the toe plantar flexion muscles.

[Purpose] The purpose of this study was to determine the functional differences of the plantar flexion muscles of the hallux and lesser toes during the single leg stance by comparing postural sway in different conditioning contraction interventions. [Subjects] Thirty-four healthy, young males and females participated in this study. [Methods] The front-back and right-left direction components of maximal displacement and postural sway velocity during the single leg stance were measured in various conditioning contraction interventions for the plantar flexion muscles of the hallux or lessor toes. [Results] The main findings of this study were as follows: 1) the front-back direction component of maximal displacement was reduced by conditioning contraction of the plantar flexion muscles of the hallux, and 2) the front-back direction component of the postural sway velocity was reduced by conditioning contraction of the plantar flexion muscles of the lesser toes during the single leg stance. [Conclusion] The plantar flexion muscles of the lesser toes control the postural sway velocity. Furthermore, the plantar flexion muscles of the hallux appear to control the amplitude of postural sway.

Relationship between navicular drop and measuring position of maximal plantar flexion torque of the first and second-fifth metatarsophalangeal joints.

[Purpose] The purpose of this study was to determine the relationship between navicular drop and plantar flexion torque of the first and second-fifth metatarsophalangeal joints. [Subjects] Ten healthy young men participated in this study. [Methods] The Pearson product-moment correlation coefficient was calculated to determine the relationship between navicular drop and plantar flexion torque of the first and second-fifth metatarsophalangeal joints. [Results] Significant negative correlations were observed between navicular drop and plantar flexion torques in the lengthened position of the intrinsic toe plantar flexion muscles, but no correlations were found between navicular drop and plantar flexion torques in the neutral position of the ankle and metatarsophalangeal joints. Moreover, the intrinsic toe plantar flexion muscles were found to contribute to the formation of the medial longitudinal arch. [Conclusion] Navicular drop correlates with metatarsophalangeal joint muscle strength in plantar flexion where the intrinsic toe muscles are capable of exerting force.

Neck range of motion measurements using a new three-dimensional motion analysis system: validity and repeatability.

PURPOSE: Neck movement is important for many activities of daily living (ADL). Neck disorders, such as cervical spondylosis and whiplash can limit neck movement and ADL. The cervical range of motion (CROM) device has been recently used to measure neck range of motion (ROM); however, this measurement includes trunk motion, and therefore does not represent a pure neck ROM measurement. The authors aimed to develop a new method to establish pure neck ROM measurements during flexion, extension, lateral bending, and rotation using a three-dimensional motion analysis system, VICON. METHODS: Twelve healthy participants were recruited and neck ROMs during flexion, extension, lateral bending, and rotation were measured using VICON and the CROM device. Test-retest repeatability was assessed using interclass correlation coefficients (ICCs), standard error of measurement (SEM), and minimal detectable change (MDC). Validity between two measurements was evaluated using a determination coefficient and Pearson's correlation coefficient. RESULTS: ICCs of neck ROM measured using VICON and the CROM device were all at substantial or almost perfect levels [VICON: ICC(1,2) = 0.786-0.962, the CROM device: ICC(1,2) = 0.736-0.950]. Both SEMs and MDCs were low in all measurement directions (VICON: SEM = 1.3°-4.5°, MDC = 3.6°-12.5°; the CROM device: SEM = 2.2°-3.9°, MDC = 6.1°-10.7°). Determination coefficients (R(2)s) and Pearson's correlation coefficients (rs) between the two measurement methods were high (R(2) = 0.607-0.745, r = 0.779-0.863). CONCLUSIONS: VICON is a useful system to measure neck ROMs and evaluate the efficacy of interventions, such as surgery or physiotherapeutic exercise.

Novel 3-dimensional motion analysis method for measuring the lumbar spine range of motion: repeatability and reliability compared with an electrogoniometer.

STUDY DESIGN: Repeatability and reliability for measuring methods for real-time lumbar range of motion. OBJECTIVE: We established a novel set of marker positions for 3-dimensional motion analysis (VICON system) to determine lumbar spine range of motion (LROM) and lumbar motion precisely; we compared the repeatability and reliability of VICON system with those of an electrogoniometer. SUMMARY OF BACKGROUND DATA: The assessment of the LROM using x-ray is still one of the most precise methods, despite the radiation exposure. To avoid this, alternative methods, such as the VICON system and electrogoniometer, have been widely used. No study has reported the repeatability and reliability of LROM measurements using a VICON system and electrogoniometer. METHODS: The VICON system and electrogoniometer measured LROM and lumbar motion in 7 healthy males during 7 days. Differences between both systems were analyzed using Bland-Altman plots. Repeatability and reliability of the LROM measurements was assessed using coefficients of multiple correlations and intraclass correlation coefficients, respectively. Standard error of measurement was calculated to quantify the systematic error in LROM measurements. RESULTS: The mean maximum LROM values using the VICON system/electrogoniometer were 42°/52° for flexion, 17°/24° for extension, 16°/16° for lateral bending, and 8°/2° for axial rotation, respectively. Between VICON system and the electrogoniometer, Bland-Altman plots revealed no discrepancies in LROM values except for flexion.Coefficients of multiple correlations for LROM showed excellent repeatability. LROM measurements with VICON system showed excellent reliability for flexion and extension and fair-to-good reliability for other motions. LROM measurements with the electrogoniometer showed excellent reliability for flexion and fair-to-good reliability for other motions. Except for axial rotation, maximum intraclass correlation coefficients using VICON system were more reliable than the electrogoniometer for measuring lumbar motion. CONCLUSION: VICON system with our novel marker set allows practical and reliable longitudinal assessment of dynamic LROM. LEVEL OF EVIDENCE: N/A.

Vertical peak ground force in human infant crawling.

Quadrupedalism is a common mode of locomotion in land animals. The load distribution between the forelimbs (FL) and hindlimbs (HL) in quadrupedalism has been of great interest to researchers, and a database of the vertical peak force (Vpk) for FL and HL has been created for various species. However, Vpk in human infant crawling, a natural form of human quadrupedalism, has not been evaluated. We aimed to study Vpk in human infant crawling. Eight healthy infants who used a typical crawling style (i.e., crawling on the hands and knees) were included. The infants were encouraged to crawl over pressure mats placed on the floor, and Vpk of FL and HL were calculated. FL Vpk was 0.631±0.087 (per BW), and HL Vpk was 0.638±0.089 (per BW). No significant difference was observed between FL and HL Vpk. The mean FL/HL Vpk ratio was -0.011 on a natural logarithmic scale. These data could be added to the current database on Vpk for quadrupedalism.