Abstracts / Gait & Posture 30S (2009) S1–S153 O6 References Re-adaptations in gait after bariatric surgery-induced weight loss [1] [2] [3] [4] Tibor Hortobágyi 1,∗ , Cortney Herring 1 , Patrick Rider 1 , Jonathan Patterson 1 , Benjamin Long 1 , Kelly Jernigan 2 , John Pender 2 , Bill Chapman 2 , Walter Pories 2 , Paul DeVita 1 1 East Carolina University, Department of Exercise and Sport Science, Greenville, NC, United States 2 East Carolina University, Department of Surgery, Greenville, NC, United States Summary We report preliminary data on the effects of massive weight loss on gait kinematics and kinetics. There were substantial readaptations after weight loss in gait kinematics and kinetics, including increases in stride length and gait speed as well as reductions in vertical ground reaction forces, frontal plane adduction torques, and normalized ankle plantarflexion torques. Conclusion Weight loss 6 months after bariatric surgery partially restored stride characteristics and gait biomechanics in the sagittal and frontal planes resembled that of lean adults. Introduction Many clinical conditions evoke adaptations in gait [1–4]. Obese vs. lean adults walk more slowly and with a more erect posture. It is unknown if such adaptations become hard-wired with obesity or there is a rapid re-adaptation of obese gait to lean gait after weight loss. The purpose of this study was to examine the effects of extreme weight loss on human locomotion 6 months following bariatric surgery. Methods 3D lower limb kinematics and kinetics were assessed prior to (n = 5, BMI = 46.8) and 6 months after (n = 5, BMI = 32.7) bariatric surgery. Subjects walked at their self selected pace and the results of five acceptable trials were averaged. Results Following surgery, subjects had significantly longer stride lengths (1.42–1.49 m, p < 0.05). There were also large reductions in vertical ground reaction forces (1032–736 N, p < 0.05), and frontal plane average knee torques (−27.3 to −20.9 N m, p < 0.05). Increases in normalized (body weight × height) sagittal plane maximal ankle plantar flexor torque (7.7–8.5 N m/kg m, p < 0.05) and normalized (body weight) sagittal plane ankle work (0.003–0.049 J/kg, p < 0.05) were observed. Discussion The longer stride length appeared to be driven by the increased torque and work production at the ankle joint. The extreme amount of weight loss contributed to a large reduction in overall external loads placed on each individual. This resulted in large reductions in frontal plane torques at the knee joint to overcome the reduced external loads. The frontal plane knee torque result was especially significant since it is well documented that increased knee adduction torque is a predictor of knee osteoarthritis (OA), which may suggest that due to the significant weight loss, these individuals are less likely to develop knee OA. These data suggest a partial restoration of lean gait after surgery-induced large weight loss in obese adults, with disproportionately large changes in some variables. Acknowledgement Supported by NIH R01AG024161. S5 DeVita P, Hortobágyi T. J Appl Physiol 2000;88:1804–11. DeVita P, et al. Med Sci Sports Exerc 1998;30:1481–8. Levin MF, et al. Brain Res 2000;853:352–69. Rudolph KS, et al. Phys Ther 2007;87:1422–32. doi:10.1016/j.gaitpost.2009.08.010 O7 Kinematic comparative study for spastic equinus conservative treatment. A new option to consider Sergio Lerma Lara ∗ , Ignacio Martínez Caballero, Andrés Castillo Sanz, Tomás Epeldegui Torre Hospital Infantil Universitario Niño Jesús., Madrid, Spain Summary We presented a kinematic comparative study between three therapeutic conservative options for the treatment of spastic equinus. Btx-A alone for flexible equinus and for the less flexible ones casting after Btx-A and the new management option which is Btx-A Between Casting period (the “BBC” group). We found statistically significant differences in dorsiflexion angle at initial contact, dynamic range of motion of the ankle during the gait cycle and the step length. Conclusions According to our study, casting in ankle dorsiflexion, followed by another week with the same cast, for spastic equinus gait treatment is proved to be worth considering. Introduction Different studies comparing Botulin toxin A (Btx-A) alone, or in combination with casting for spastic equinus gait, have been already published [2,3]. According the last systematic review of the topic there is no evidence that order of treatment (casting before Btx-A versus Btx-A before casting) affects outcome [1]. To our knowledge, this is the first time the Btx-A has been used during a casting treatment, and its results compared with other well-known conservative strategies treatment for spastic equinus. Participants/material and methods All the participants (45) were children with cerebral palsy, GMFCS level II, with a mean age of 9 years, (range 5–16), 25 males and 20 females. Thirty-five patients were hemiplegic and 10 diplegic with an equinus gait. Exclusion criteria were equinus varus, plano-valgus deformities and torsional or neurological problems. We have used 3–4 U/kg of Botox (Allergan® ) for the gastrocnemius, and the cases were distributed in the three different treatment groups. Kinematic analysis was performed pre- and posttreatment (4–5 weeks later). Three kinematic values obtained from the sagittal graphs and two spatio-temporal parameters were used to evaluate the results: - KV I – Flexion ankle angle at initial contact. - KV II – Maximum dorsiflexion in stance phase. - KV III – Range of motion between maximum dorsiflexion in stance and maximum plantar flexion at the swing phase. - Velocity (m/s). - Step length (m). Results Good clinical results were reported in KV I, KV II and KVIII in every group. Comparing the kinematic data. The Group three (the