NSFC-RSE Joint Project (81911530253), National Key R&#38;D Program of China (2018YFF0300905), and K. C. Wong Magna Fund in Ningbo University.

The Human Ethics Committee of Ningbo University approved this experiment. All written informed consent was obtained from all subjects after they were told about the goal, requirements, and experimental procedures of the UGT experiment.
1. Laboratory preparation for gait
<ol>
	<li>Kinematics: Motion capture system
	<ol>
		<li>When calibrating the system, turn off the incandescent lights and remove any possible reflective objects that can be mistaken for passive retro-reflective markers. Ensur...

<ol>
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E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kinetic+analysis+of+planned+gait+termination+in+healthy+subjects+and+patients+with+balance+disorders.">Kinetic analysis of planned gait termination in healthy subjects and patients with balance disorders.</a> Gait &amp; Posture. 17 (2), 170-179 (2003).</li><li>Bishop, M., Brunt, D., Pathare, N., Patel, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effect+of+velocity+on+the+strategies+used+during+gait+termination.">The effect of velocity on the strategies used during gait termination.</a> Gait &amp; Posture. 20 (2), 134-139 (2004).</li><li>Ridge, S. T., Henley, J., Manal, K., Miller, F., Richards, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biomechanical+analysis+of+gait+termination+in+11&#8211;17year+old+youth+at+preferred+and+fast+walking+speeds.">Biomechanical analysis of gait termination in 11&#8211;17year old youth at preferred and fast walking speeds.</a> Human Movement Science. 49, 178-185 (2016).</li><li>Sun, D., Fekete, G., Mei, Q., Gu, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effect+of+walking+speed+on+the+foot+inter-segment+kinematics,+ground+reaction+forces+and+lower+limb+joint+moments.">The effect of walking speed on the foot inter-segment kinematics, ground reaction forces and lower limb joint moments.</a> PeerJ. 6, 5517 (2018).</li><li>Eerdekens, M., Deschamps, K., Staes, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+impact+of+walking+speed+on+the+kinetic+behaviour+of+different+foot+joints.">The impact of walking speed on the kinetic behaviour of different foot joints.</a> Gait &amp; Posture. 68, 375-381 (2019).</li><li>Wang, Z. p., Qiu, Q. e., Chen, S. h., Chen, B. c., Lv, X. t. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+Unstable+Shoes+on+Lower+Limbs+with+Different+Speeds.">Effects of Unstable Shoes on Lower Limbs with Different Speeds.</a> Physical Activity and Health. 3, 82-88 (2019).</li><li>Tirosh, O., Sparrow, W. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Age+and+walking+speed+effects+on+muscle+recruitment+in+gait+termination.">Age and walking speed effects on muscle recruitment in gait termination.</a> Gait &amp; Posture. 21 (3), 279-288 (2005).</li><li>Xiang, L., Mei, Q., Fernandez, J., Gu, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+biomechanical+assessment+of+the+acute+hallux+abduction+manipulation+intervention.">A biomechanical assessment of the acute hallux abduction manipulation intervention.</a> Gait &amp; Posture. 76, 210-217 (2020).</li><li>Zhou, H., Ugbolue, U. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Is+There+a+Relationship+Between+Strike+Pattern+and+Injury+During+Running:+A+Review.">Is There a Relationship Between Strike Pattern and Injury During Running: A Review.</a> Physical Activity and Health. 3 (1), 127-134 (2019).</li><li>Serrao, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sudden+Stopping+in+Patients+with+Cerebellar+Ataxia.">Sudden Stopping in Patients with Cerebellar Ataxia.</a> The Cerebellum. 12 (5), 607-616 (2013).</li><li>Zhang, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Using+Gold-standard+Gait+Analysis+Methods+to+Assess+Experience+Effects+on+Lower-limb+Mechanics+During+Moderate+High-heeled+Jogging+and+Running.">Using Gold-standard Gait Analysis Methods to Assess Experience Effects on Lower-limb Mechanics During Moderate High-heeled Jogging and Running.</a> Journal of Visualized Experiments. (127), e55714 (2017).</li><li>Buddhadev, H. H., Barbee, C. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Redistribution+of+joint+moments+and+work+in+older+women+with+and+without+hallux+valgus+at+two+walking+speeds.">Redistribution of joint moments and work in older women with and without hallux valgus at two walking speeds.</a> Gait &amp; Posture. 77, 112-117 (2020).</li><li>Yu, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Morphology-Related+Foot+Function+Analysis:+Implications+for+Jumping+and+Running.">Morphology-Related Foot Function Analysis: Implications for Jumping and Running.</a> Applied Sciences. 9 (16), 3236 (2019).</li><li>Ridge, S. T., Henley, J., Manal, K., Miller, F., Richards, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kinematic+and+kinetic+analysis+of+planned+and+unplanned+gait+termination+in+children.">Kinematic and kinetic analysis of planned and unplanned gait termination in children.</a> Gait &amp; Posture. 37 (2), 178-182 (2013).</li><li>Burnfield, J. M., Few, C. D., Mohamed, O. S., Perry, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+influence+of+walking+speed+and+footwear+on+plantar+pressures+in+older+adults.">The influence of walking speed and footwear on plantar pressures in older adults.</a> Clinical Biomechanics. 19 (1), 78-84 (2004).</li><li>Cen, X., Xu, D., Baker, J. S., Gu, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+additional+body+weight+on+arch+index+and+dynamic+plantar+pressure+distribution+during+walking+and+gait+termination.">Effect of additional body weight on arch index and dynamic plantar pressure distribution during walking and gait termination.</a> PeerJ. 8, 8998 (2020).</li><li>Chatzipapas, C. N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stress+Fractures+in+Military+Men+and+Bone+Quality+Related+Factors.">Stress Fractures in Military Men and Bone Quality Related Factors.</a> International Journal of Sports Medicine. 29 (11), 922-926 (2008).</li><li>Cen, X., Xu, D., Baker, J. S., Gu, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Association+of+Arch+Stiffness+with+Plantar+Impulse+Distribution+during+Walking,+Running,+and+Gait+Termination.">Association of Arch Stiffness with Plantar Impulse Distribution during Walking, Running, and Gait Termination.</a> International Journal of Environmental Research and Public Health. 17 (6), 2090 (2020).</li></ol>

No potential conflict of interest was reported by the authors.

Most previous studies that analyze gait biomechanics during UGT omit the importance of walking speed in their biomechanical assessment. Thus, this study investigated the lower-limb biomechanical changes that occur in UGT at NWS and FWS with the aim to reveal the speed-related effects.
Significant differences have been found on the ROM of the hip, knee, and ankle joints in the sagittal plane during UGT at NWS and FWS. Our findings showed greater ROMs of the 3 joints in the sagittal plane during...

Human locomotion is considered to be an extremely complex process that needs to be described by multidisciplinary methods1,2. The most representative aspect is the gait analysis by biomechanical approaches. Human gait aims to sustain progression from initiation to termination, and the dynamic balance should be maintained in position movement. Although gait termination (GT) has been extensively studied as a sub-task of gait, it has received less attention. Sparrow and Tirosh3 defined GT in their review as motor control period when both feet stop moving either forward or backward based on the displacement and time characteristics. Compared to steady-state gait, the process of executing GT demands higher control of postural stability and complex integration and cooperation of the neuromuscular system4. During GT, the body needs to rapidly increase the braking impulse and decrease propulsion impulse to form a new body balance5,6. Unplanned gait termination (UGT) is a stress response to an unknown stimulus6. When confronted by an unexpected stimulus that requires one to stop suddenly, initial dynamic balance will be disrupted. Because of the need for the continuous control of the body&#8217;s center of mass (COM) and feedback control, UGT poses a greater challenge to postural control and stablity3,7.
UGT has been reported to be an important factor leading to falls and injuries, especially in elderly people and patients with balance disorders3,8. Faster walking speeds may lead to an additional decline in motor control during UGT9. Ridge et al.10 investigated the peak joint angle and internal joint moment data of children during UGT at normal walking speed (NWS) and fast walking speed (FWS). The results showed larger knee flexion angles and extension moments at faster speeds compared with preferred speed. They indicated that strengthening the related muscles surrounding the lower extremity joints could be a useful intervention for injury prevention during UGT.
Although the effect of walking speed on the lower-limb biomechanical character during steady-state gait has been extensively studied11,12,13, the biomechanical mechanism of UGT under different walking speeds is limited. To our knowledge, only three studies have specifically evaluated healthy individuals&#8217; UGT performances with respect to velocity effects9,10,14. However, subjects in these studies were mainly the elderly14 and children10, the biomechanical mechanism of young adults during UGT is still unclear. Lower-limb kinematics and plantar pressure can provide a precise analysis of locomotion biomechanics, and these are also considered to be crucial components for clinical gait diagnoses15,16. For example, Serrao et al.17 used lower-limb kinematic data to detect the clinical differences between patients with cerebellar ataxia and healthy counterparts during sudden stopping. Besides, compared to planned gait termination (PGT), larger peak pressure and force in the lateral metatarsal during UGT could be observed7, which may be associated with higher injury risks.
Therefore, exploring the biomechanical mechanisms of UGT could provide insights for injury prevention and further clinical researches. This study presents a protocol to investigate any biomechanical alteration in young adults during UGT under different walking speeds. It is hypothesized that, with an increase in walking speed, participants would exhibit different lower-limb biomechanical characteristics during UGT.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr >
			<td >14 mm Diameter Passive Retro-reflective Marker</td>
			<td >Oxford Metrics Ltd., Oxford, UK</td>
			<td >n=16</td>
		</tr>
		<tr >
			<td >Double Adhesive Tape</td>
			<td >Minnesota Mining and Manufacturing Corporation, Minnesota, USA</td>
			<td>For fixing markers to skin</td>
		</tr>
		<tr >
			<td >Motion Tracking Cameras</td>
			<td >Oxford Metrics Ltd., Oxford, UK</td>
			<td>n= 8</td>
		</tr>
		<tr >
			<td >T-Frame</td>
			<td >Oxford Metrics Ltd., Oxford, UK</td>
			<td>-</td>
		</tr>
		<tr >
			<td >Valid Dongle</td>
			<td >Oxford Metrics Ltd., Oxford, UK</td>
			<td>Vicon Nexus 1.4.116</td>
		</tr>
		<tr >
			<td >Vicon Datastation ADC&#160;</td>
			<td >Oxford Metrics Ltd., Oxford, UK</td>
			<td>-</td>
		</tr>
		<tr >
			<td >Pressure platform</td>
			<td >RSscan International, Olen, Belgium</td>
			<td>-</td>
		</tr>
	</tbody>
</table>

lower-limb biomechanical characteristics associated with unplanned gait termination under different walking speeds

Gait termination caused by unexpected stimulus is a common occurrence in everyday life. This study presents a protocol to investigate the lower-limb biomechanical changes that occur during unplanned gait termination (UGT) under different walking speeds. Fifteen male participants were asked to perform UGT on a walkway at normal walking speed (NWS) and fast walking speed (FWS), respectively. A motion analysis system and plantar pressure platform were applied to collect lower-limb kinematic and plantar pressure data. Paired-sampled T-test was used to examine the differences in lower-limb kinematics and plantar pressure data between two walking speeds. The results showed larger range of motion in the hip, knee, and ankle joints in the sagittal plane as well as plantar pressure in forefoot and heel regions during UGT at FWS when compared with NWS. With the increase in walking speed, subjects exhibited different lower-limb biomechanical characteristics that show FWS associated with greater potential injury risks.

Mean &#38; SD values of NWS and FWS of 15 subjects were 1.33 &#177; 0.07m/s and 1.62 &#177; 0.11m/s, respectively.
Figure 3 shows the mean ROM of the hip, knee, and ankle joints in the sagittal plane during UGT at NWS and FWS. Compared with NWS, the ROM of three joints increased significantly at FWS (p&#60;0.05). In detail, the ROM of hip, knee and ankle joints increased from 22.26 &#177; 3.03, 29.72 &#177; 5.14 and 24.92 &#177; 4.17 to 25.98 &#177; 2.94, 31.61 &#...

Watch this Scientific Journal Video about Lower-Limb Biomechanical Characteristics Associated with Unplanned Gait Termination Under Different Walking Speeds at JoVE.com

Lower-Limb Biomechanical Characteristics Associated with Unplanned Gait Termination Under Different Walking Speeds

This study compared the biomechanical characteristics of the lower extremity during unplanned gait termination under different walking speeds. The lower-limb kinematic and kinetic data from fifteen subjects with normal and fast walking speeds were collected using a motion analysis system and plantar pressure platform.

Gait termination caused by unexpected stimulus is a common occurrence in everyday life. This study presents a protocol to investigate the lower-limb ...

This measure can be used to investigate key question in lower-limb biomechanical characteristics that are occurring during unplanned gait termination under different walking speeds. The main advantage of this technique is that it can prove some specific details for exploring potential injury risks associated with gait termination. Before the test interview all subjects and provide them with a simple explanation about the experimental goals and procedures.Obtain written informed consent from subjects who meet the key inclusion criteria. Include subjects who are physically active male adults, have the right leg as dominant, do not have any hearing disorder, do not have lower-limb disorders, and have not incurred injuries in the last 6 months. Instruct all subjects to fill out a survey with questions such as have you had a history of running or other physical activities?How often do you do physical activities in a week? Do you have any professional athletic training? And have you suffered any lower-limb disorders and injuries in the last 6 months?Ensure that all subjects wear identical t-shirts and tight-fitting pants. Measure subject standing height and body weight, lower-limb length, knee width, and ankle with of both left and right leg using a Vernier caliper or a small anthropometer. Shave off body hair where appropriate and remove excess sweat using alcohol wipes to prepare skin areas of anatomical bony landmarks for marker placement on joints and segments.Identify 16 anatomical landmarks and attach passive retroreflective markers with double-sided adhesive tapes. Give each subject 5 minutes to adapt to the test environment and warm up with light running and stretching. Once the subject is at the starting position, open the kinematics motion capture system, select the Go Live button in the resources pane, and click Capture in the right tool bar.Find trial type and session and edit the trial description. Ask subjects to walk along a walkway at their normal walking speed and instruct them to use the dominant and non-dominant leg to pass areas A and B respectively, and then to stop at area D on the pressure platform. Let the subject know that when the termination signal is provided, they need to quickly stop at B.Randomly provide the termination signal as the heel touches area A ensuring that the unexpected gait termination or UGT is executed.After finishing the UGT test click stop to end the data collection trial. Capture at least 5 success of UGT trials with 2 minute rest intervals between trials. Calculate each subject's walking speed using the pressure platform software, then calculate the fast walking speed as 125%of the normal walking speed.To calculate plantar pressure select the measure button before starting the UGT trials. After finishing the UGT test, click save measurement button to save the data. Repeat the test at fast walking speed to capture at least 5 successive trials.This protocol was used to compare the biomechanical characteristics of the lower extremity during unplanned gait termination under different walking speeds. Data was collected from 15 subjects. Mean normal and fast walking speeds of the subjects were 1.33 and 1.62 meters per second respectively.The mean range of motion of the hip, knee, and ankle joints in the sagittal plane during unplanned gait termination at normal and fast walking speeds is shown here. Compared with normal walking speed, the range of motion of 3 joints increased significantly at fast walking speed. The plantar pressure data, including maximum pressure, maximum force, and contact area during unplanned gait termination is shown here.Compared with normal walking speed, the maximum pressure in BT, M1, M2, M3, MH, and LH regions increased significantly at fast walking speed. Similarly, the maximum force increased significantly in BT, M1, M2, M3, MH, and LH at fast walking speed. Differences in contact area occurred in the heel region, MH and LH, both increasing at fast walking speed.No significant difference occurred in any parameters for the OT, M4, M5, and MF regions. During this procedure the effect of different speeds was different static patterns on muscle activities and the joint moments during gait termination can be researched. Gait termination tries could be used as effective tool for diagnoses of clinical biomechanical performance and assessment of a rehabilitation treatment.

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4.4K Görüntüleme.  Ningbo University. This measure can be used to investigate key question in lower-limb biomechanical characteristics that are occurring during unplanned gait termination under different walking speeds. The main advantage of this technique is that it can prove some specific details for exploring potential injury risks associated with gait termination. Before the test interview all subjects and provide them with a simple explanation about the experimental goals and procedures.Obtain written informed consent...