Susumu Ota

The influence of in-season injury prevention training on lower-extremity kinematics during landing in female soccer players.

ObjectiveTo examine the influence of in-season injury prevention training on hip and knee kinematics during a landing task. DesignLongitudinal pre-post intervention study. SettingTesting sessions were conducted in a biomechanics research laboratory. ParticipantsEighteen female soccer players between the ages of 14 and 17 participated in this study. All subjects were healthy with no current complaints of lower extremity injury. InterventionsTesting sessions were conducted prior to and following a season of soccer practice combined with injury prevention training. Main Outcome MeasurementsDuring each testing session three-dimensional kinematics were collected while each subject performed a drop landing task. Peak hip and knee joint angles were measured during the early deceleration phase of landing and compared between pre- and post-training using paired t-tests. ResultsFollowing a season of soccer practice combined with injury prevention training, females demonstrated significantly less hip internal rotation (7.1° vs. 1.9°; P=0.01) and significantly greater hip abduction (−4.9° vs. −7.7°; P=0.02). No differences in knee valgus or knee flexion angles were found post-season. ConclusionsFemale soccer players exhibited significant changes in hip kinematics during a landing task following in-season injury prevention training. Our results support the premise that a season of soccer practice combined with injury prevention training is effective in altering lower extremity motions that may play a role in predisposing females to ACL injury.

Predictors of Frontal Plane Knee Excursion During a Drop Land in Young Female Soccer Players

STUDY DESIGN Controlled laboratory study using a cross-sectional, single testing session. OBJECTIVE To determine the association between frontal plane knee excursion during a drop land task and measures of hip strength, and ankle and hip range of motion. BACKGROUND Assessment of frontal plane knee excursion during a drop land task has been advocated as a means to screen for potentially injurious lower extremity movement patterns. Accordingly, an understanding of the physical characteristics associated with the magnitude of frontal plane knee excursion could assist clinicians in developing interventions and prevention strategies to minimize injury risk. METHODS AND MEASURES Thirty-nine female high school soccer players (mean +/- SD age, 15.5 +/- 1.0 years; height, 162.2 +/- 5.3 cm; body mass, 56.8 +/- 6.7 kg) participated. Isometric hip muscle strength as well as ankle and hip range of motion measurements were obtained using standard clinical procedures and a handheld dynamometer. Frontal plane knee excursion was assessed using a 6-camera motion analysis system during a drop land task. Using 3-dimensional coordinate data, maximum frontal plane knee excursion was defined as the difference between the distances of right and left lateral knee markers at initial contact and maximum knee flexion during the deceleration phase of landing. Independent variables found to be significantly correlated with frontal plane knee excursion were then entered into a stepwise multiple regression procedure to determine the best set of predictors of this motion. RESULTS Hip external rotation range of motion and ankle dorsiflexion range of motion were found to be negatively correlated with frontal plane knee excursion (r=-0.40, P=.005 and r=-0.27, P=.05, respectively). Together they accounted for 27% of the variance in frontal plane knee excursion (r=0.52, P=.03). No relationships between measures of hip strength and frontal plane knee excursion were found. CONCLUSIONS Frontal plane knee excursion during a drop land task was partially attributed to available range of motion at the hip and ankle. These results suggest that range of motion of the joints proximal and distal to the knee should be considered when evaluating individuals who present with excessive frontal plane knee excursion during this task. Given that the relationship between range of motion and frontal plane knee excursion was small, other factors, including learned motor patterns, should be considered.

Acute influence of restricted ankle dorsiflexion angle on knee joint mechanics during gait

BACKGROUND Restrictions in range of ankle dorsiflexion (DF) motion can persist following ankle injuries. Ankle DF is necessary during terminal stance of gait, and its restricted range may affect knee joint kinematics and kinetics. The purpose of this study was to investigate the acute influence of varied levels of restricted ankle DF on knee joint sagittal and frontal plane kinematics and kinetics during gait. METHODS Thirty healthy volunteers walked with a custom-designed ankle brace that restricted ankle DF. Kinematics and kinetics were collected using a 7-camera motion analysis system and two force plates. Ankle dorsiflexion was restricted in 10-degree increments, allowing for four conditions: Free, light (LR), moderate (MR) and severe restriction (SR). Knee angles and moments were measured during terminal stance. RESULTS Real peak ankle DF for Free, LR, MR, and SR were 13.7±4.8°, 11.6±5.0°, 7.5±5.3°, and 4.2±7.2°, respectively. Peak knee extension angles under the same conditions were -6.7±6.7°, -5.4±6.4°, -2.5±7.5°, and 0.6±7.8°, respectively, and the peak knee varus moment was 0.48±0.17 Nm/kg, 0.47±0.17 Nm/kg, 0.53±0.20 Nm/kg, and 0.57±0.20 Nm/kg. The knee varus moment was significantly increased from MR condition with an 8-degree restriction in ankle DF. CONCLUSION Knee joint kinematics and kinetics in the sagittal and frontal planes were affected by reduced ankle DF during terminal stance of gait. Differences were observed with restriction in ankle DF range of approximately 8°. LEVEL OF EVIDENCE level III.

Prognostic factors of synkinesis after Bell's palsy and Ramsay Hunt syndrome

OBJECTIVE This study evaluated the prognostic factors of synkinesis following Bells palsy and Ramsay Hunt syndrome. METHODS A total of 345 patients consisting of 309 cases of Bells palsy and 36 cases of Ramsay Hunt syndrome were enrolled in our study. The following 13 factors were considered as candidate prognostic factors for the presence of synkinesis at 6 months from onset: age, sex, diagnosis, diabetes mellitus, initial onset or recurrence, electroneurography (ENoG), number of days from onset to first visit to our hospital, the lowest Yanagihara grading system score, the change in Yanagihara score after 1 month, otalgia, hearing loss, vertigo and taste disturbances. These factors were analyzed by logistic regression. RESULTS Logistic regression analysis clarified the lowest Yanagihara score, the change in Yanagihara score after 1 month, and the ENoG value for a prognosis of synkinesis. The most predictive prognostic factor was the lowest Yanagihara score, and the adjusted odds ratio in the multivariate model was 11.415. As for other prognostic factors, the adjusted odds ratios ranged from 7.017 (ENoG value) to 8.310 (the change in Yanagihara score after 1 month). These findings were therefore considered as high risk factors for synkinesis. CONCLUSION It is possible to predict synkinesis following Bells palsy and Ramsay Hunt syndrome on the basis of clinical symptoms. The lowest Yanagihara score, and the change in Yanagihara score after 1 month, together with the ENoG value at the onset, were found to be especially important factors for predicting synkinesis following Bells palsy and Ramsay Hunt syndrome.

Comparison of Patellar Mobility in Female Adults With and Without Patellofemoral Pain

STUDY DESIGN Case control study. OBJECTIVE To compare the patellar mobility of female adult subjects with and without patellofemoral pain (PFP). BACKGROUND Although abnormal patellar mobility is believed to be one of the causes of PFP, there is currently no published evidence to support this contention. In part, this lack of evidence is because a reliable clinical measurement method to measure patellar mobility and objective criteria to define abnormal patellar mobility have not been established. METHODS AND MEASURES The study sample was comprised of 22 females with PFP (PFP group) and 22 females who had no knee pain (control group), matched by age, height, and body mass index to the subjects with PFP. Patellar mobility was measured objectively using a specially designed apparatus. Measurements of lateral and medial patellar displacement, patellar mobility balance (lateral minus medial patellar displacement), lateral patellar mobility index (lateral patellar displacement divided by patellar width), and medial patellar mobility index (medial patellar displacement divided by patellar width) were used. RESULTS Lateral and medial patellar mobility values were not significantly different between the individuals in the PFP and control groups. When normal patellar mobility was arbitrarily defined as the average mobility +/- 2 SDs, based on the data from the control group, normal lateral patellar displacement was within a range of 7.2 to 17.6 mm and normal medial patellar displacement was within a range of 6.8 to 14.0 mm. The intraclass correlation coefficient for intratester and intertester reliability of lateral and medial patellar displacement measurements varied from 0.80 to 0.97. CONCLUSION Although there were no significant differences in patellar mobility between females with and without PFP, these measurements give reference information about normal patellar mobility for this group. LEVEL OF EVIDENCE Diagnosis, level 5.

Relationship between standing postural alignments and physical function among elderly women using day service centers in Japan

BACKGROUND Posture and physical function have been quantified in mature adults, but not in elderly females. OBJECTIVE To quantify standing posture and measures of physical function in community-dwelling women over the age of 65 years, and to examine relationships between these variables. METHODS Fifty-three women were recruited from day care service users (average age: 83.7 ±6.3 years old). Standing postural alignments were assessed using 2-dimensional analyses with a digital video camera. The time up and go test (TUG) and other physical function tests were conducted. RESULTS Decreased lower cervical angle (increased forward head position) was significantly correlated with increased upper cervical angle (increased chin-up, r = −0.45), increased thoracic spine angle (increased kyphosis, r = −0.38), and decreased lumbar spine angle (thoracolumbar segments backward relative to the pelvis, r = 0.48). The decreased lumbar spine angle was significantly correlated with increased thoracic angle (increased kyphosis, r = −0.37), increased pelvic plane angle (increased anterior pelvic tilt, r = −0.49), and decreased knee flexion angle (r = 0.46). Increased TUG time (slower walking speed) was correlated to increased forward head position (r = 0.30) and thoracolumbar segments forward relative to the pelvis (r = 0.34). CONCLUSIONS Posture and physical function measures were provided for community-dwelling females who were >65 years of age. They did not demonstrate any correlation between measured knee strength, back strength or single leg standing with measures of postural alignment, but TUG showed a moderate correlation with the lower cervical and lumbar spine posture measures.

Does the Q − H index show a stronger relationship than the H:Q ratio in regard to knee pain during daily activities in patients with knee osteoarthritis?

[Purpose] The purpose of this study was to elucidate the relationship between knee muscle strength and knee pain in activities of daily living, based on consideration of the difference between extension and flexion strength (Q − H) and the hamstring:quadriceps (H:Q) ratio in patients with knee osteoarthritis. [Subjects and Methods] The participants were 78 females with knee osteoarthritis, and a total of 133 knees that had not been treated surgically were the targets of this research. The legs were divided according to dominance. Isometric knee extension and flexion muscle strength and knee pain during activities of daily living were measured. The H:Q ratio (flexion/extension muscle strength) and the difference between extension and flexion strength, (extension muscle strength/weight) minus (flexion muscle strength/weight), that is, Q − H, were calculated. The correlation between these indices and the knee pain score during activities of daily living was investigated. [Results] Greater knee pain during activities of daily living was related to lower knee extension muscle strength and Q − H in both the dominant and nondominant legs. Knee flexion muscle strength and the H:Q ratio were not significantly correlated with knee pain during any activities of daily living. [Conclusion] Knee extension muscle strength and Q − H were found to be significantly correlated with knee pain during activities of daily living, whereas the H:Q ratio was not.

Does decrease of the thoracic kyphosis influence decrease knee adduction moment during gait? A preliminary study of a healthy population

[Purpose] The purpose of this study was to investigate the influence of a decrease in thoracic kyphosis angle on the knee adduction moment during gait in healthy young individuals. [Subjects and Methods] Twenty-nine healthy adults, consisting of 15 males and 14 females (21.6 ± 1.1 years old), participated. The draw-in maneuver was used to decrease thoracic kyphosis, and thoracic kyphosis was measured using a SpinalMouse during normal standing and standing with the draw-in maneuver. The participants were required to maintain the draw-in maneuver during gait. A 3-D motion analysis system and a force plate were used to obtain knee adduction moment. [Results] Thoracic kyphosis angles during the draw-in maneuver (41.0 ± 7.4 degrees) were significantly decreased compared with the angles during normal standing (43.0 ± 7.9 degrees). Although the knee adduction moment during gait with the draw-in maneuver was not significantly decreased compared with that during level gait, in the 20 subjects who had decreased kyphosis due to the draw-in maneuver, the 1st peak knee adduction moment (55.7 ± 24.3 × 10−3) with the draw-in maneuver was significantly decreased compared with the knee adduction moment (57.0 ± 16.3 × 10−3) during level gait. [Conclusion] Knee adduction moment in the case of a decreased thoracic kyphosis angle due to the draw-in maneuver was decreased compared with that during level gait.

Beneficial effects of a gait used while wearing a kimono to decrease the knee adduction moment in healthy adults

The knee adduction moment (KAM) relates to medial knee osteoarthritis (OA). Several gait modifications to reduce the KAM for the prevention of knee OA have been studied. Most of the modifications, however, involve voluntary changes in leg alignment. Here we investigated the biomechanical effects for reducing the KAM of a walking style with a small trunk rotation and arm swing gait, which is a natural walking style used while wearing a kimono (Nanba walk) that shifts the ground reaction force toward the stance leg (reduced lever arm). Twenty-nine healthy adults (21.5 ± 0.6 years) participated in the present study. A three-dimensional analysis system with 10 cameras and 1 force plate was used to obtain the KAM and other biomechanical data. Surface electromyography (EMG) of the hip and trunk muscles (internal obliquus abdominal muscle: IO, external obliquus abdominal muscle: EO, multifidus muscle: MF, and gluteus medius muscle: Gmed) was also assessed, and integrated EMG (iEMG) of the four muscles was assessed in the first and second halves of the stance phase. The 1st and 2nd peak KAMs were significantly decreased during Nanba walking (0.40±0.09 and 0.37±0.13 Nm/kg) compared with normal walking (0.45±0.09 and 0.45±0.13 Nm/kg; P = 0.002, P<0.001, respectively). The lever arm lengths at the 1st and 2nd peak KAMs were also significantly decreased during Nanba walking compared with normal walking (p = 0.023 and p<0.001, respectively). The iEMGs of IO, EO and Gmed muscles during the first half, and the iEMGs of EO and GM during the second half of the stance phase were significantly increased during Nanba walking compared with normal walking. The Nanba gait modification could be a useful strategy for reducing the KAM with high activation of the trunk and hip joint muscles for the prevention and/or treatment of medial knee OA.

Is latero-medial patellar mobility related to the range of motion of the knee joint after total knee arthroplasty?

Diminished range of motion (ROM) of the knee joint after total knee arthroplasty (TKA) is thought to be related to reduced patellar mobility. This has not been confirmed clinically due to a lack of quantitative methods adequate for measuring patellar mobility. We investigated the relationship between patellar mobility by a reported quantitative method and knee joint ROM after TKA. Forty-nine patients [osteoarthritis--OA: 29 knees; rheumatoid arthritis--RA: 20 knees] were examined after TKA. Respective medial and lateral patellar mobility was measured 1 and 6 months postoperatively using a patellofemoral arthrometer (PFA). Knee joint ROM was also measured in each of those 2 sessions. Although the flexion and extension of the knee joints improved significantly from 1 to 6 months after TKA, the medial and lateral patellar displacements (LPDs) failed to improve during that same period. Moreover, only the changes in knee flexion and medial patellar displacement (MPD) between the two sessions were positively correlated (r = 0.31, p < 0.05). However, our findings demonstrated that medial and lateral patellar mobility had no sufficient longitudinal relationship with knee ROM after TKA.