1
Yu-Lin You,
2Chien-Fen Lin,
1Fong-Chin Su
2Lan-Yuen Guo
1 Department of Biomedical Engineering, National Cheng Kung University, Tainan 701, Taiwan 2 Department of Sports Medicine, College of Medicine, Kaohsiung Medical University,
Step characteristics and step variability may predict fall
risk which is likely related to stability
There’s an association between step width and falls in
elderly
Thus, the application of step width may improve
dynamic balance during walking
Heitmann et al. (1989) Paterson et al. (2011)
Step width during walking
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It increased with age
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Wider step width would increase energy expenditure
Subjects who suffer from balance deficit showed wider
step width during walking
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Hemiplegic patients
The muscle activation ratio of vastus medialis oblique (VMO)
and vastus lateralis (VL) was increased during narrow step
width walking in normal subjects
Owings and Grabiner (2004); Roerdink et al. (2007);
Lin et al. (2006)
The muscle activation ratio of VMO and VL was
decreased in patellofemoral pain syndrome (PFPS)
patients
Etiology of PFPS: patella was pulled abnormally due to
imbalanced VMO and VL
VMO activation increased may improve symptoms of
PFPS
Narrow step width may be applicable on PFPS
Voight et al. (1991) Cowan et al. (2001)
To our knowledge, there are few studies investigated
the difference of biomechanics among different step
widths
To investigate the differences of biomechanics on lower
Subjects
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12 healthy subjects (7 females and 5 males)
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Mean age was 22.90 (2.64) years old
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Mean height was 166.67 (3.80) cm
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Mean weight was 60.33 (7.37) kg
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Exclusion criteria
Any major surgery or trauma to the lower extremity within six
months
Equipment
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Three-D motion analysis system (Qualisys Oqus 100, Qualisys
Oqus-CMOS, Qualisys AB, Swenden)
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Two force plates (9286AA,9286A, Kistler Instrument Corp,
Winterhur, Switzerland)
Subjects were instructed to walk in a cadence of 96 steps
per minute
The different step widths were in randomized order
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5 cm
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10 cm
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15 cm
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20 cm
Every step width was carried out for 3 trials
Primary outcomes included the
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Kinematics and kinetics of lower extremity
Repeated measurement of analysis of variance (SPSS
12.0, Chicago, IL, USA) was used to evaluate the
differences of biomechanical characteristics among
these conditions
Ankle plantar flexion (-) and dorsi flexion (+) angle, (degree)
Stance phase Pre-swing phase P-values Mean ± SD Step widths 5cm 10cm 15cm 20cm 15.20±4.38 13.63±3.94 13.46±3.32 13.16±9.65 -21.41±6.29 -22.74±7.95 -22.44±5.10 -24.71±14.04 >0.05
Hip extension (-) and flexion (+) angle, (degree) Mean ± SD P-values Step widths 5cm 10cm 15cm 20cm -1.33±9.79 -1.86±9.86 -2.38±10.21 -2.42±9.65 >0.05
Ankle inversion (-) and eversion (+) angle, (degree) Mean ± SD P-values Step widths 5cm 10cm 15cm 20cm -6.48±0.34 -4.72±1.06 -5.05±0.57 -4.19±0.30 >0.05
Hip adduction (-) and abduction (+) angle, (degree) Mean ± SD P-values Step widths 5cm 10cm 15cm 20cm 6.82±3.40 7.12±3.42 8.84±5.33 9.66±5.93 >0.05
Ground reaction force
Medial side (-) and lateral side (+), (%BW)
Mean ± SD P-values Step widths 5cm 10cm 15cm 20cm -0.07±0.08 -0.10±0.09 -0.11±0.09 -0.11±0.07 <0.05 Post-hoc comparison 5cm<20cm 10cm<20cm
Plantar flexor (-) and dorsi flexor (+) moments, (N-m) Mean ± SD P-values Step widths 5cm 10cm 15cm 20cm -1.23±0.10 -1.22±0.12 -1.23±0.12 -1.17±0.15 <0.05 Post-hoc comparison 5cm>20cm 10cm>20cm 15cm>20cm
Hip joint moment in sagittal plane
Flexor (-) and extensor (+) moments, (N-m)
Mean ± SD P-values Step widths 5cm 10cm 15cm 20cm 0.30±0.30 0.41±0.27 0.54±0.52 0.67±0.52 <0.05 Post-hoc comparison 20cm>10cm 20cm >5cm
Knee joint moment in frontal plane
Valgus (-) and varus (+) moments, (N-m)
Mean ± SD P-values Step widths 5cm 10cm 15cm 20cm -0.21±0.13 -0.19±0.16 -0.20±0.22 -0.20±0.15 >0.05
Knee joint moment in transverse plane
Internal rotator (-) and external rotator (+) moments, (N-m)
Mean ± SD P-values Step widths 5cm 10cm 15cm 20cm 0.10±0.05 0.11±0.02 0.11±0.12 0.12±0.10 >0.05
The narrow step width showed the more ankle
inversion angle
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Ankle arch ↑
Pes planus patients
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Flat foot
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Decreased statibility
Narrow step width may be applied to pes planus patients as a
gait training manipulation factor in order to improve the
stability
Wider step width
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Hip extension and abduction angle increased during stance
phase
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Hip extensor moment increased
These results may increase the stress on the posterolateral side
of hip joint
The wider step width
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GRF at medial side increased
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The GRF at medial side increased was due to the increase of
ankle eversion angle and further increase the contact area at
medial side
Foot pressure study found that the foot pressure increased at
medial side during wide step width walking
Wider step width
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Knee external rotator moment ↑
PFPS runners showed greater knee external rotator moment than
non-injured runners
The muscle activation ratio of VMO and VL was increased during
narrow step width walking in normal subjects
Narrow step width
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Knee valgus
moment ↑
Prevent knee osteoarthritis (OA)
Stefanyshyn et al. (2006)
Narrow step width
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Greater ankle inversion angle which increase arch height
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Greater knee valgus moment
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Smaller knee external rotation moment
