Different forms of locomotion in the spinal lamprey

Effects of backward walking on knee proprioception after ACL reconstruction

Objective: The present study aimed to assess proprioception of the knee to evaluate the effectiveness of backward walking for rehabilitation after anterior cruciate ligament (ACL) reconstruction.Methods: Patients (n = 52) who underwent ACL reconstruction in a single knee divided randomly into four experimental groups (A-D) and a control group, who all practiced a systematic rehabilitation exercise program. The patients in the experimental groups underwent backward walking using different treadmill angles: group A (0°), B (5°), C (10°) and D (15°). The whole training period comprised 4 weeks. Outcomes for the joint were assessed using the Angle Reproduction Test (ART) and Passive Motion Perception Test (PMPT).Results: Compared with the pre-training recorded parameters, significant differences were found in the ART and PMPT scores among all training groups and between the control group and the training groups. When the four training groups were compared with each other, there was no difference in the ART results between groups A and B, but significant differences were found between group A and groups C and D.Conclusion: Backward walking as a rehabilitation technique improved knee proprioception after ACL reconstruction. Increasing the angle of the treadmill during exercise improved the efficacy of rehabilitation.

Kinematics of forward and backward locomotion performed in different environmental conditions

Mice are frequently used in analyses of the locomotor system. Although forward locomotion (FWL) in intact mice has been studied previously, backward locomotion (BWL) in mice has never been analyzed. The aim of the present study was to compare kinematics of FWL and BWL performed in different environmental conditions (i.e., in a tunnel, on a treadmill, and on an air-ball). In all setups, the average speed and step amplitude during BWL were significantly reduced compared with FWL. The cycle duration varied greatly during both FWL and BWL. The average swing duration during BWL was twice shorter than during FWL on each setup. Mice exhibited different interlimb coordinations (trot and walk with lateral or diagonal sequence) during BWL but only one gait (walk with lateral sequence) during FWL. Location of the rostro-caudal paw trajectory in relation to the hip projection to the surface (HP) depended on hip height. With low hip height, the trajectory was displaced either rostrally (anterior steps) or caudally (posterior steps) to HP. With high hip height, HP was near the middle of the trajectory (middle steps). During FWL, all three forms of steps were observed in the tunnel and predominantly anterior and posterior steps on the treadmill and air-ball, respectively. During BWL, only anterior steps were observed. Intralimb coordination depended on the form of stepping. Limb joints were coordinated to keep the hip at approximately constant height during stance and to have the smallest functional limb length during swing when the limb passed under the hip.NEW & NOTEWORTHY Mice are extensively used for the analysis of the locomotor system. This study is the first examination of the kinematics of forward and backward locomotor movements in different environmental conditions in mice. Obtained results represent a benchmark for studies based on manipulations of activity of specific populations of neurons to reveal their roles in control of specific aspects of locomotion.

Nervous mechanisms of locomotion in different directions

Locomotion, that is active propulsive movement of the body in space, is a vital motor function. Intensive studies of the main, for the majority of living beings, form of locomotion, forward locomotion, have revealed essential features of the organization and operation of underlying neural mechanisms. However, animals and humans are capable to locomote not only forward but also in other directions in relation to the body axis, e.g. backward, sideways, etc. Single steps in different directions are also used for postural corrections during locomotion and during standing. Recent studies of mechanisms underlying control of locomotion in different directions have greatly expanded our knowledge about locomotor system and can contribute to improvement of rehabilitation strategies aimed at restoration of locomotion and balance control in patients. This review outlines recent advances in the studies of locomotion in different directions in lower and higher vertebrates, with special attention given to the neuronal locomotor mechanisms.

The effects of backward walking training on balance and mobility in an individual with chronic incomplete spinal cord injury: A case report

BACKGROUND/PURPOSE

Individuals with incomplete spinal cord injuries (ISCIs) commonly face persistent gait impairments. Backward walking training may be a useful rehabilitation approach, providing novel gait and balance challenges. However, little is known about the effects of this approach for individuals with ISCIs. The purpose of this case report was to describe the effects of backward walking training on strength, balance, and upright mobility in an individual with chronic ISCI.

METHODS

A 28-year-old female, 11-years post ISCI (C4, AIS D) completed 18-sessions of backward walking training on a treadmill with partial body-weight support and overground. Training emphasized stepping practice, speed, and kinematics. Outcome measures included: Lower Extremity Motor Score, Berg Balance Scale (BBS), Sensory Organization Test (SOT), 10-Meter Walk Test (10MWT), 3-meter backward walking test, Timed Up and Go (TUG), and Activities-Specific Balance Confidence (ABC) Scale.

RESULTS

Strength did not change. Improved balance was evident based on BBS (20 to 37/56) and SOT scores (27 to 40/100). Upright mobility improved based on TUG times (57 to 32.7 s), increased 10MWT speed (0.23 to 0.31 m/s), and backward gait speed (0.07 to 0.12 m/s). Additionally, self-reported balance confidence (ABC Scale) increased from 36.9% to 49.6%.

CONCLUSIONS

The results suggest that backward walking may be a beneficial rehabilitation approach; examination of the clinical efficacy is warranted.

Flexibility of the axial central pattern generator network for locomotion in the salamander

In tetrapods, limb and axial movements are coordinated during locomotion. It is well established that inter- and intralimb coordination show considerable variations during ongoing locomotion. Much less is known about the flexibility of the axial musculoskeletal system during locomotion and the neural mechanisms involved. Here we examined this issue in the salamander Pleurodeles waltlii, which is capable of locomotion in both aquatic and terrestrial environments. Kinematics of the trunk and electromyograms from the mid-trunk epaxial myotomes were recorded during four locomotor behaviors in freely moving animals. A similar approach was used during rhythmic struggling movements since this would give some insight into the flexibility of the axial motor system. Our results show that each of the forms of locomotion and the struggling behavior is characterized by a distinct combination of mid-trunk motor patterns and cycle durations. Using in vitro electrophysiological recordings in isolated spinal cords, we observed that the spinal networks activated with bath-applied N-methyl-d-aspartate could generate these axial motor patterns. In these isolated spinal cord preparations, the limb motor nerve activities were coordinated with each mid-trunk motor pattern. Furthermore, isolated mid-trunk spinal cords and hemicords could generate the mid-trunk motor patterns. This indicates that each side of the cord comprises a network able to generate coordinated axial motor activity. The roles of descending and sensory inputs in the behavior-related changes in axial motor coordination are discussed.