SAGITTAL AND FRONTAL LOWER LIMBS KINETICS DURING STEPPING DOWN IN TAICHI ELDERLY

Abstract

The aim was to compare the kinetic characteristics of the beginning stance phase during stepping down in Taichi and normal elderly. Nine elderly taichi subjects and eleven matched controls participated in the study. Whole body kinematics and ground reaction forces (GRF) were recorded using 10 Vicon cameras (250Hz) and two Kistler force plates (1000Hz). Sagittal and frontal kinetic parameters were calculated by using Visual3D software. Differences in variables between groups were tested using t-test. The results indicated hip extensor / knee flexor / ankle plantarflexor / support moment and peak hip/knee/ankle power were greater in Taichi group. It was concluded that Taichi group has ability to translate forward movement (hip moment / power), to control body (knee moment /power) and to absorption energy (ankle moment / power) in sagittal plane. INTRODUCTION: During stepping down, decreasing height was accompanied with potential changing to kinetic energy. Stair negotiation required higher joint moments in the lower limbs (Reeves et al., 2008B). However, physical abilities of elderly adults would decline with age, stepping down became a challenge task. Fall risks and impacts would cause daily life activities more dangerous. Injuries related to falls include muscle strains, fractures and even more serious complications. Falls during descent occur at least three times more frequently than during stair ascent (Christina & Cavanagh, 2002). View of dynamic stability, stairs descent is more challenge than ascent. Dieën et al. (2007) found that falls after unexpected stepping down were due to the inability to generate a rapid forward step, rather than due to buckling of the leading leg. That ability of elderly was poor. Bento et al. (2010) also indicated that the reduced ability to rapidly develop torque seems to be a typical characteristic in the elderly. Nadeau et al. (2003) emphasized the importance of the hip abductors in controlling the pelvis during stair negotiation, and Costigan et al. (2002) reported the significance of an internal knee abductors moment throughout stance for stabilization. Novak and Brouwer (2010) further found that hip abductor moments were larger to maintain lateral stability in the older adults. Among all exercises, Tai Chi has been promoted and is also widely accepted, and the motion characteristic is quite suitable for older people. Nowadays, many studies about the effects of Tai Chi on human body focused on physiological test, gait and balance control, while there are still few studies on joint torques cooperation of functional movement in diary environment in Tai Chi elderly adults. The purpose of this study is to investigate the sagittal and frontal lower limbs kinetics between Tai Chi exercise and normal elderly at the beginning of the stance phase when stepping down, in order to understand the effects of Tai Chi exercise on the lower extremities joint moments and power between two groups. METHOD: Nine Tai Chi elder subjects (Taichi period: 8.8±7.7years; age: 74.6±5.5 years; height: 1.63±0.06 m; weight: 61.9±6.26 kg) and eleven matched controls (age: 76.5±6.8 years; height: 1.68±0.06 m; weight: 67.75±7.23 kg) participated in the study. Ten Vicon high-speed cameras (250Hz), two force plates (1000Hz) were synchronized to collect data. Each subject performed one stepping down (20cm) and then forward walking. Sagittal and front plane kinetic parameters were calculated by kinematics and GRF using Visual3D software. Differences in kinetic variables between two groups were assessed using t-test. A significance level set α=.05.

Full text

587ISBS 2011 Porto, Portugal
Vilas-Boas, Machado, Kim, Veloso (eds.)
Biomechanics in Sports 29
Portuguese Journal of Sport Sciences
11 (Suppl. 2), 2011
SAGITTAL AND FRONTAL LOWER LIMBS KINETICS DURING STEPPING
DOWN IN TAICHI ELDERLY
Tzu-Hsiang Yang, Chen-Fu Huang and Jung-Chun Chi
Department of Physical Education, National Taiwan Normal University, Taipei, Taiwan
The aim was to compare the kinetic characteristics of the beginning stance phase during
stepping down in Taichi and normal elderly. Nine elderly taichi subjects and eleven
matched controls participated in the study. Whole body kinematics and ground reaction
forces (GRF) were recorded using 10 Vicon cameras (250Hz) and two Kistler force plates
(1000Hz). Sagittal and frontal kinetic parameters were calculated by using Visual3D
software. Differences in variables between groups were tested using t-test. The results
indicated hip extensor / knee flexor / ankle plantarflexor / support moment and peak
hip/knee/ankle power were greater in Taichi group. It was concluded that Taichi group
has ability to translate forward movement (hip moment / power), to control body (knee
moment /power) and to absorption energy (ankle moment / power) in sagittal plane.
KEY WORDS: Body control, joint moment, power
INTRODUCTION: During stepping down, decreasing height was accompanied with potential
changing to kinetic energy. Stair negotiation required higher joint moments in the lower limbs
(Reeves et al., 2008B). However, physical abilities of elderly adults would decline with age,
stepping down became a challenge task. Fall risks and impacts would cause daily life
activities more dangerous. Injuries related to falls include muscle strains, fractures and even
more serious complications. Falls during descent occur at least three times more frequently
than during stair ascent (Christina & Cavanagh, 2002). View of dynamic stability, stairs
descent is more challenge than ascent.
Dieën et al. (2007) found that falls after unexpected stepping down were due to the inability
to generate a rapid forward step, rather than due to buckling of the leading leg. That ability of
elderly was poor. Bento et al. (2010) also indicated that the reduced ability to rapidly develop
torque seems to be a typical characteristic in the elderly. Nadeau et al. (2003) emphasized
the importance of the hip abductors in controlling the pelvis during stair negotiation, and
Costigan et al. (2002) reported the significance of an internal knee abductors moment
throughout stance for stabilization. Novak and Brouwer (2010) further found that hip abductor
moments were larger to maintain lateral stability in the older adults.
Among all exercises, Tai Chi has been promoted and is also widely accepted, and the motion
characteristic is quite suitable for older people. Nowadays, many studies about the effects of
Tai Chi on human body focused on physiological test, gait and balance control, while there
are still few studies on joint torques cooperation of functional movement in diary environment
in Tai Chi elderly adults. The purpose of this study is to investigate the sagittal and frontal
lower limbs kinetics between Tai Chi exercise and normal elderly at the beginning of the
stance phase when stepping down, in order to understand the effects of Tai Chi exercise on
the lower extremities joint moments and power between two groups.
METHOD: Nine Tai Chi elder subjects (Taichi period: 8.8±7.7years; age: 74.6±5.5 years;
height: 1.63±0.06 m; weight: 61.9±6.26 kg ) and eleven matched controls (age: 76.5±6.8
years; height: 1.68±0.06 m; weight: 67.75±7.23 kg) participated in the study. Ten Vicon high-
speed cameras (250Hz), two force plates (1000Hz) were synchronized to collect data. Each
subject performed one stepping down (20cm) and then forward walking. Sagittal and front
plane kinetic parameters were calculated by kinematics and GRF using Visual3D software.
Differences in kinetic variables between two groups were assessed using t-test. A
significance level set α=.05.

588ISBS 2011 Porto, Portugal
Vilas-Boas, Machado, Kim, Veloso (eds.)
Biomechanics in Sports 29
Portuguese Journal of Sport Sciences
11 (Suppl. 2), 2011
DISCUSSION: Sagittal Plane: Compared to previous study, we could find that the hip joint
moment during stepping down was greater than those with stair descent (Table 5). It
speculated that hip extensor moment at the beginning of the stand phase during stepping
down could “put” the trunk forward, for translation movement to forward and prevent trunk
forward rotation. Peak hip extensor moment found in the Taichi group (1.32 Nm/kg) is greater
than that in the control group (0.44 Nm/kg), it means Taichi group would have better ability to
generate forward trunk motion while one step descent.
Dieën et al. (2007) found that peak knee extensor moment occurred during expected
stepping down. In our study, we found that peak knee moment performed during knee flexed
at the beginning of stand phase. Checking for video, the trailing leg still supported upon the
step while knee flexor moment acted. Our results also showed that peak knee flexor moment
(0.71 and 0.43 Nm/kg) larger than previous studies (0.18 ~ 0.40 Nm/kg) of descent (Table 6).
It suggested that knee flexors would move the COP closer to the knee joint center thereby
reducing the external knee moment (Salsich et al., 2001). Taichi group had greater knee
flexor moment than control group, it caused by greater body control in Taichi group.
Table 6
Sagittal peak knee joint moments compared to previous study
Moment (Nm/kg)
Peak Knee Extensor
Peak Knee Flexor
Stair Descent
Salsich et al. (2001)
0.68
0.22
Protopapadaki et al. (2007)
0.14
0.40
Beaulieu et al. (2008)
1.00
0.18
Reeves et al. (2008)
0.75
0.23
One stepping down
Dieën et al. (2007)
2.01
0.84
present study (taichi)
0.44
0.71
present study (control)
0.28
0.43
Ankle moments predominantly contributed to extensor support in the sagittal plane (Novak &
Brouwer, 2010). Lark (2004) indicated that ankle joint producted nearly all the support during
the single-stance phase of gait. Our findings displayed similar with previous studies. As stair
descent, the older adults used “toe landing” more often than young adults (Dieën &
Pijnappels, 2009; Dieën et al., 2007). Toe landing produced more negative work by leading
leg to reduce the kinetic energy that body gain, forward velocity, and prevented balance loss.
Riener et al. (2002) found that stair descent showed a strong ankle power absorptions.
Table 2 showed the sagittal plane lower limbs power. Both groups presented positive hip and
knee power at the beginning of stand phase, only ankle power was negative. It showed that
ankle plantarflexor muscles lengthen (eccentric contraction) for absorption the energy body
gains. Taichi group (-7.17 W/kg) had greater negative ankle plantarflexor power than control
group (-4.92 W/kg), it seemed to indicate Taichi group had better ability to absorb energy and
prevent balance loss while stepping down.
All of lower limb joints power in Taichi group were greater than Control group. It mean that
Taichi group would has better ability to translate to forward movement (hip moment/power),
to control body (knee moment /power) and to absorption energy (ankle moment / power) in
sagittal plane.
RESULTS: The data of sagittal and frontal lower limb joints moment / power are shown in
Table 1 to Table 4. In sagittal plane, Taichi group had greater hip extensor / knee flexor /
ankle plantarflexor / support moment and hip / knee / ankle joint power. In front plane, no
significant differences in lower limb joints moment/ power between taichi group and control
group were found.
Table 1
Sagittal peak lower limb joint moments
Max Moment
(Nm/kg)
Hip
Extensor *
Knee
Flexor *
Knee
Extensor
Ankle
Plantarflexor *
Support
Moment *
TaiChi group
1.32±0.50
0.71±0.27
0.44±0.22
1.43±0.16
2.25±0.34
Control group
0.59±0.34
0.43±0.09
0.29±0.21
1.23±0.28
1.59±0.48
*p<.05
Table 2
Sagittal peak lower limbs power
Max Power (W/kg)
Hip joint *
Knee joint *
Ankle joint *
TaiChi group
0.68±0.30
1.73±1.15
-7.17±0.74
Control group
0.32±0.19
0.93±0.51
-4.92±1.38
*p<.05
Table 3
Frontal peak lower limb joint moments
Max Power (W/kg)
Hip Abductor
Knee Abductor
Ankle Invertor
TaiChi group
0.97±0.20
0.41±0.18
0.36±0.14
Control group
0.99±0.18
0.42±0.11
0.43±0.17
*p<.05
Table 4
Front peak lower limbs power
Max Power (W/kg)
Hip joint
Knee joint
Ankle joint
TaiChi group
-0.56±0.24
-0.23±0.26
-0.14±0.09
Control group
-0.57±0.24
-0.20±0.16
-0.19±0.15
*p<.05
Table 5
Sagittal peak lower limb joint moments compared to previous study
Peak moment (Nm/kg)
Hip
Extensor
Knee
Extensor
Ankle
Plantarflexor
Support
Stair Descent
Salsich et al. (2001)
0.53
0.78
1.47
2.16
Protopapadaki et al. (2007)
0.52
0.46
1.38
Beaulieu et al. (2008)
0.42
1.0
1.05
1.55
Reeves et al. (2008)
-
0.83
1.03
One stepping down
Dieën et al. (2007)
1.42
2.01
1.80
present study (taichi)
1.32
0.44
1.43
2.25
present study (control)
0.59
0.29
1.26
1.59
RESULTS: The data of sagittal and frontal lower limb joints moment / power are shown in
Table 1 to Table 4. In sagittal plane, Taichi group had greater hip extensor / knee flexor /
ankle plantarflexor / support moment and hip / knee / ankle joint power. In front plane, no
significant differences in lower limb joints moment/ power between taichi group and control
group were found.
Table 1
Sagittal peak lower limb joint moments
Max Moment
(Nm/kg)
Hip
Extensor *
Knee
Flexor *
Knee
Extensor
Ankle
Plantarflexor *
Support
Moment *
TaiChi group
1.32±0.50
0.71±0.27
0.44±0.22
1.43±0.16
2.25±0.34
Control group
0.59±0.34
0.43±0.09
0.29±0.21
1.23±0.28
1.59±0.48
*p<.05
Table 2
Sagittal peak lower limbs power
Max Power (W/kg)
Hip joint *
Knee joint *
Ankle joint *
TaiChi group
0.68±0.30
1.73±1.15
-7.17±0.74
Control group
0.32±0.19
0.93±0.51
-4.92±1.38
*p<.05
Table 3
Frontal peak lower limb joint moments
Max Power (W/kg)
Hip Abductor
Knee Abductor
Ankle Invertor
TaiChi group
0.97±0.20
0.41±0.18
0.36±0.14
Control group
0.99±0.18
0.42±0.11
0.43±0.17
*p<.05
Table 4
Front peak lower limbs power
Max Power (W/kg)
Hip joint
Knee joint
Ankle joint
TaiChi group
-0.56±0.24
-0.23±0.26
-0.14±0.09
Control group
-0.57±0.24
-0.20±0.16
-0.19±0.15
*p<.05
Table 5
Sagittal peak lower limb joint moments compared to previous study
Peak moment (Nm/kg)
Hip
Extensor
Knee
Extensor
Ankle
Plantarflexor
Support
Stair Descent
Salsich et al. (2001)
0.53
0.78
1.47
2.16
Protopapadaki et al. (2007)
0.52
0.46
1.38
Beaulieu et al. (2008)
0.42
1.0
1.05
1.55
Reeves et al. (2008)
-
0.83
1.03
One stepping down
Dieën et al. (2007)
1.42
2.01
1.80
present study (taichi)
1.32
0.44
1.43
2.25
present study (control)
0.59
0.29
1.26
1.59
RESULTS: The data of sagittal and frontal lower limb joints moment / power are shown in
Table 1 to Table 4. In sagittal plane, Taichi group had greater hip extensor / knee flexor /
ankle plantarflexor / support moment and hip / knee / ankle joint power. In front plane, no
significant differences in lower limb joints moment/ power between taichi group and control
group were found.
Table 1
Sagittal peak lower limb joint moments
Max Moment
(Nm/kg)
Hip
Extensor *
Knee
Flexor *
Knee
Extensor
Ankle
Plantarflexor *
Support
Moment *
TaiChi group
1.32±0.50
0.71±0.27
0.44±0.22
1.43±0.16
2.25±0.34
Control group
0.59±0.34
0.43±0.09
0.29±0.21
1.23±0.28
1.59±0.48
*p<.05
Table 2
Sagittal peak lower limbs power
Max Power (W/kg)
Hip joint *
Knee joint *
Ankle joint *
TaiChi group
0.68±0.30
1.73±1.15
-7.17±0.74
Control group
0.32±0.19
0.93±0.51
-4.92±1.38
*p<.05
Table 3
Frontal peak lower limb joint moments
Max Power (W/kg)
Hip Abductor
Knee Abductor
Ankle Invertor
TaiChi group
0.97±0.20
0.41±0.18
0.36±0.14
Control group
0.99±0.18
0.42±0.11
0.43±0.17
*p<.05
Table 4
Front peak lower limbs power
Max Power (W/kg)
Hip joint
Knee joint
Ankle joint
TaiChi group
-0.56±0.24
-0.23±0.26
-0.14±0.09
Control group
-0.57±0.24
-0.20±0.16
-0.19±0.15
*p<.05
Table 5
Sagittal peak lower limb joint moments compared to previous study
Peak moment (Nm/kg)
Hip
Extensor
Knee
Extensor
Ankle
Plantarflexor
Support
Stair Descent
Salsich et al. (2001)
0.53
0.78
1.47
2.16
Protopapadaki et al. (2007)
0.52
0.46
1.38
Beaulieu et al. (2008)
0.42
1.0
1.05
1.55
Reeves et al. (2008)
-
0.83
1.03
One stepping down
Dieën et al. (2007)
1.42
2.01
1.80
present study (taichi)
1.32
0.44
1.43
2.25
present study (control)
0.59
0.29
1.26
1.59
RESULTS: The data of sagittal and frontal lower limb joints moment / power are shown in
Table 1 to Table 4. In sagittal plane, Taichi group had greater hip extensor / knee flexor /
ankle plantarflexor / support moment and hip / knee / ankle joint power. In front plane, no
significant differences in lower limb joints moment/ power between taichi group and control
group were found.
Table 1
Sagittal peak lower limb joint moments
Max Moment
(Nm/kg)
Hip
Extensor *
Knee
Flexor *
Knee
Extensor
Ankle
Plantarflexor *
Support
Moment *
TaiChi group
1.32±0.50
0.71±0.27
0.44±0.22
1.43±0.16
2.25±0.34
Control group
0.59±0.34
0.43±0.09
0.29±0.21
1.23±0.28
1.59±0.48
*p<.05
Table 2
Sagittal peak lower limbs power
Max Power (W/kg)
Hip joint *
Knee joint *
Ankle joint *
TaiChi group
0.68±0.30
1.73±1.15
-7.17±0.74
Control group
0.32±0.19
0.93±0.51
-4.92±1.38
*p<.05
Table 3
Frontal peak lower limb joint moments
Max Power (W/kg)
Hip Abductor
Knee Abductor
Ankle Invertor
TaiChi group
0.97±0.20
0.41±0.18
0.36±0.14
Control group
0.99±0.18
0.42±0.11
0.43±0.17
*p<.05
Table 4
Front peak lower limbs power
Max Power (W/kg)
Hip joint
Knee joint
Ankle joint
TaiChi group
-0.56±0.24
-0.23±0.26
-0.14±0.09
Control group
-0.57±0.24
-0.20±0.16
-0.19±0.15
*p<.05
Table 5
Sagittal peak lower limb joint moments compared to previous study
Peak moment (Nm/kg)
Hip
Extensor
Knee
Extensor
Ankle
Plantarflexor
Support
Stair Descent
Salsich et al. (2001)
0.53
0.78
1.47
2.16
Protopapadaki et al. (2007)
0.52
0.46
1.38
Beaulieu et al. (2008)
0.42
1.0
1.05
1.55
Reeves et al. (2008)
-
0.83
1.03
One stepping down
Dieën et al. (2007)
1.42
2.01
1.80
present study (taichi)
1.32
0.44
1.43
2.25
present study (control)
0.59
0.29
1.26
1.59
RESULTS: The data of sagittal and frontal lower limb joints moment / power are shown in
Table 1 to Table 4. In sagittal plane, Taichi group had greater hip extensor / knee flexor /
ankle plantarflexor / support moment and hip / knee / ankle joint power. In front plane, no
significant differences in lower limb joints moment/ power between taichi group and control
group were found.
Table 1
Sagittal peak lower limb joint moments
Max Moment
(Nm/kg)
Hip
Extensor *
Knee
Flexor *
Knee
Extensor
Ankle
Plantarflexor *
Support
Moment *
TaiChi group
1.32±0.50
0.71±0.27
0.44±0.22
1.43±0.16
2.25±0.34
Control group
0.59±0.34
0.43±0.09
0.29±0.21
1.23±0.28
1.59±0.48
*p<.05
Table 2
Sagittal peak lower limbs power
Max Power (W/kg)
Hip joint *
Knee joint *
Ankle joint *
TaiChi group
0.68±0.30
1.73±1.15
-7.17±0.74
Control group
0.32±0.19
0.93±0.51
-4.92±1.38
*p<.05
Table 3
Frontal peak lower limb joint moments
Max Power (W/kg)
Hip Abductor
Knee Abductor
Ankle Invertor
TaiChi group
0.97±0.20
0.41±0.18
0.36±0.14
Control group
0.99±0.18
0.42±0.11
0.43±0.17
*p<.05
Table 4
Front peak lower limbs power
Max Power (W/kg)
Hip joint
Knee joint
Ankle joint
TaiChi group
-0.56±0.24
-0.23±0.26
-0.14±0.09
Control group
-0.57±0.24
-0.20±0.16
-0.19±0.15
*p<.05
Table 5
Sagittal peak lower limb joint moments compared to previous study
Peak moment (Nm/kg)
Hip
Extensor
Knee
Extensor
Ankle
Plantarflexor
Support
Stair Descent
Salsich et al. (2001)
0.53
0.78
1.47
2.16
Protopapadaki et al. (2007)
0.52
0.46
1.38
Beaulieu et al. (2008)
0.42
1.0
1.05
1.55
Reeves et al. (2008)
-
0.83
1.03
One stepping down
Dieën et al. (2007)
1.42
2.01
1.80
present study (taichi)
1.32
0.44
1.43
2.25
present study (control)
0.59
0.29
1.26
1.59
RESULTS: The data of sagittal and frontal lower limb joints moment / power are shown in
Table 1 to Table 4. In sagittal plane, Taichi group had greater hip extensor / knee flexor /
ankle plantarflexor / support moment and hip / knee / ankle joint power. In front plane, no
significant differences in lower limb joints moment/ power between taichi group and control
group were found.
Table 1
Sagittal peak lower limb joint moments
Max Moment
(Nm/kg)
Hip
Extensor *
Knee
Flexor *
Knee
Extensor
Ankle
Plantarflexor *
Support
Moment *
TaiChi group
1.32±0.50
0.71±0.27
0.44±0.22
1.43±0.16
2.25±0.34
Control group
0.59±0.34
0.43±0.09
0.29±0.21
1.23±0.28
1.59±0.48
*p<.05
Table 2
Sagittal peak lower limbs power
Max Power (W/kg)
Hip joint *
Knee joint *
Ankle joint *
TaiChi group
0.68±0.30
1.73±1.15
-7.17±0.74
Control group
0.32±0.19
0.93±0.51
-4.92±1.38
*p<.05
Table 3
Frontal peak lower limb joint moments
Max Power (W/kg)
Hip Abductor
Knee Abductor
Ankle Invertor
TaiChi group
0.97±0.20
0.41±0.18
0.36±0.14
Control group
0.99±0.18
0.42±0.11
0.43±0.17
*p<.05
Table 4
Front peak lower limbs power
Max Power (W/kg)
Hip joint
Knee joint
Ankle joint
TaiChi group
-0.56±0.24
-0.23±0.26
-0.14±0.09
Control group
-0.57±0.24
-0.20±0.16
-0.19±0.15
*p<.05
Table 5
Sagittal peak lower limb joint moments compared to previous study
Peak moment (Nm/kg)
Hip
Extensor
Knee
Extensor
Ankle
Plantarflexor
Support
Stair Descent
Salsich et al. (2001)
0.53
0.78
1.47
2.16
Protopapadaki et al. (2007)
0.52
0.46
1.38
Beaulieu et al. (2008)
0.42
1.0
1.05
1.55
Reeves et al. (2008)
-
0.83
1.03
One stepping down
Dieën et al. (2007)
1.42
2.01
1.80
present study (taichi)
1.32
0.44
1.43
2.25
present study (control)
0.59
0.29
1.26
1.59

589ISBS 2011 Porto, Portugal
Vilas-Boas, Machado, Kim, Veloso (eds.)
Biomechanics in Sports 29
Portuguese Journal of Sport Sciences
11 (Suppl. 2), 2011
DISCUSSION: Sagittal Plane: Compared to previous study, we could find that the hip joint
moment during stepping down was greater than those with stair descent (Table 5). It
speculated that hip extensor moment at the beginning of the stand phase during stepping
down could “put” the trunk forward, for translation movement to forward and prevent trunk
forward rotation. Peak hip extensor moment found in the Taichi group (1.32 Nm/kg) is greater
than that in the control group (0.44 Nm/kg), it means Taichi group would have better ability to
generate forward trunk motion while one step descent.
Dieën et al. (2007) found that peak knee extensor moment occurred during expected
stepping down. In our study, we found that peak knee moment performed during knee flexed
at the beginning of stand phase. Checking for video, the trailing leg still supported upon the
step while knee flexor moment acted. Our results also showed that peak knee flexor moment
(0.71 and 0.43 Nm/kg) larger than previous studies (0.18 ~ 0.40 Nm/kg) of descent (Table 6).
It suggested that knee flexors would move the COP closer to the knee joint center thereby
reducing the external knee moment (Salsich et al., 2001). Taichi group had greater knee
flexor moment than control group, it caused by greater body control in Taichi group.
Table 6
Sagittal peak knee joint moments compared to previous study
Moment (Nm/kg) Peak Knee Extensor Peak Knee Flexor
Stair Descent
Salsich et al. (2001) 0.68 0.22
Protopapadaki et al. (2007) 0.14 0.40
Beaulieu et al. (2008) 1.00 0.18
Reeves et al. (2008) 0.75 0.23
One stepping down
Dieën et al. (2007) 2.01 0.84
present study (taichi) 0.44 0.71
present study (control) 0.28 0.43
Ankle moments predominantly contributed to extensor support in the sagittal plane (Novak &
Brouwer, 2010). Lark (2004) indicated that ankle joint producted nearly all the support during
the single-stance phase of gait. Our findings displayed similar with previous studies. As stair
descent, the older adults used “toe landing” more often than young adults (Dieën &
Pijnappels, 2009; Dieën et al., 2007). Toe landing produced more negative work by leading
leg to reduce the kinetic energy that body gain, forward velocity, and prevented balance loss.
Riener et al. (2002) found that stair descent showed a strong ankle power absorptions.
Table 2 showed the sagittal plane lower limbs power. Both groups presented positive hip and
knee power at the beginning of stand phase, only ankle power was negative. It showed that
ankle plantarflexor muscles lengthen (eccentric contraction) for absorption the energy body
gains. Taichi group (-7.17 W/kg) had greater negative ankle plantarflexor power than control
group (-4.92 W/kg), it seemed to indicate Taichi group had better ability to absorb energy and
prevent balance loss while stepping down.
All of lower limb joints power in Taichi group were greater than Control group. It mean that
Taichi group would has better ability to translate to forward movement (hip moment/power),
to control body (knee moment /power) and to absorption energy (ankle moment / power) in
sagittal plane.
DISCUSSION: Sagittal Plane: Compared to previous study, we could find that the hip joint
moment during stepping down was greater than those with stair descent (Table 5). It
speculated that hip extensor moment at the beginning of the stand phase during stepping
down could “put” the trunk forward, for translation movement to forward and prevent trunk
forward rotation. Peak hip extensor moment found in the Taichi group (1.32 Nm/kg) is greater
than that in the control group (0.44 Nm/kg), it means Taichi group would have better ability to
generate forward trunk motion while one step descent.
Dieën et al. (2007) found that peak knee extensor moment occurred during expected
stepping down. In our study, we found that peak knee moment performed during knee flexed
at the beginning of stand phase. Checking for video, the trailing leg still supported upon the
step while knee flexor moment acted. Our results also showed that peak knee flexor moment
(0.71 and 0.43 Nm/kg) larger than previous studies (0.18 ~ 0.40 Nm/kg) of descent (Table 6).
It suggested that knee flexors would move the COP closer to the knee joint center thereby
reducing the external knee moment (Salsich et al., 2001). Taichi group had greater knee
flexor moment than control group, it caused by greater body control in Taichi group.
Table 6
Sagittal peak knee joint moments compared to previous study
Moment (Nm/kg)
Peak Knee Extensor
Peak Knee Flexor
Stair Descent
Salsich et al. (2001)
0.68
0.22
Protopapadaki et al. (2007)
0.14
0.40
Beaulieu et al. (2008)
1.00
0.18
Reeves et al. (2008)
0.75
0.23
One stepping down
Dieën et al. (2007)
2.01
0.84
present study (taichi)
0.44
0.71
present study (control)
0.28
0.43
Ankle moments predominantly contributed to extensor support in the sagittal plane (Novak &
Brouwer, 2010). Lark (2004) indicated that ankle joint producted nearly all the support during
the single-stance phase of gait. Our findings displayed similar with previous studies. As stair
descent, the older adults used “toe landing” more often than young adults (Dieën &
Pijnappels, 2009; Dieën et al., 2007). Toe landing produced more negative work by leading
leg to reduce the kinetic energy that body gain, forward velocity, and prevented balance loss.
Riener et al. (2002) found that stair descent showed a strong ankle power absorptions.
Table 2 showed the sagittal plane lower limbs power. Both groups presented positive hip and
knee power at the beginning of stand phase, only ankle power was negative. It showed that
ankle plantarflexor muscles lengthen (eccentric contraction) for absorption the energy body
gains. Taichi group (-7.17 W/kg) had greater negative ankle plantarflexor power than control
group (-4.92 W/kg), it seemed to indicate Taichi group had better ability to absorb energy and
prevent balance loss while stepping down.
All of lower limb joints power in Taichi group were greater than Control group. It mean that
Taichi group would has better ability to translate to forward movement (hip moment/power),
to control body (knee moment /power) and to absorption energy (ankle moment / power) in
sagittal plane.
RESULTS: The data of sagittal and frontal lower limb joints moment / power are shown in
Table 1 to Table 4. In sagittal plane, Taichi group had greater hip extensor / knee flexor /
ankle plantarflexor / support moment and hip / knee / ankle joint power. In front plane, no
significant differences in lower limb joints moment/ power between taichi group and control
group were found.
Table 1
Sagittal peak lower limb joint moments
Max Moment
(Nm/kg)
Hip
Extensor *
Knee
Flexor *
Knee
Extensor
Ankle
Plantarflexor *
Support
Moment *
TaiChi group
1.32±0.50
0.71±0.27
0.44±0.22
1.43±0.16
2.25±0.34
Control group
0.59±0.34
0.43±0.09
0.29±0.21
1.23±0.28
1.59±0.48
*p<.05
Table 2
Sagittal peak lower limbs power
Max Power (W/kg)
Hip joint *
Knee joint *
Ankle joint *
TaiChi group
0.68±0.30
1.73±1.15
-7.17±0.74
Control group
0.32±0.19
0.93±0.51
-4.92±1.38
*p<.05
Table 3
Frontal peak lower limb joint moments
Max Power (W/kg)
Hip Abductor
Knee Abductor
Ankle Invertor
TaiChi group
0.97±0.20
0.41±0.18
0.36±0.14
Control group
0.99±0.18
0.42±0.11
0.43±0.17
*p<.05
Table 4
Front peak lower limbs power
Max Power (W/kg)
Hip joint
Knee joint
Ankle joint
TaiChi group
-0.56±0.24
-0.23±0.26
-0.14±0.09
Control group
-0.57±0.24
-0.20±0.16
-0.19±0.15
*p<.05
Table 5
Sagittal peak lower limb joint moments compared to previous study
Peak moment (Nm/kg)
Hip
Extensor
Knee
Extensor
Ankle
Plantarflexor
Support
Stair Descent
Salsich et al. (2001)
0.53
0.78
1.47
2.16
Protopapadaki et al. (2007)
0.52
0.46
1.38
Beaulieu et al. (2008)
0.42
1.0
1.05
1.55
Reeves et al. (2008)
-
0.83
1.03
One stepping down
Dieën et al. (2007)
1.42
2.01
1.80
present study (taichi)
1.32
0.44
1.43
2.25
present study (control)
0.59
0.29
1.26
1.59

590ISBS 2011 Porto, Portugal
Vilas-Boas, Machado, Kim, Veloso (eds.)
Biomechanics in Sports 29
Portuguese Journal of Sport Sciences
11 (Suppl. 2), 2011
Table 7
Front peak lower limb joint moments compared to previous study
Peak moment (Nm/kg)
Hip Abductor
Knee Abductor
Ankle Invertor
Novak and Brouwer (2010)
0.74
0.39
0.12
present study (taichi)
0.97
0.41
0.36
present study (control)
0.99
0.42
0.43
Frontal plane: No significant differences in hip abductor/ knee abductor/ ankle plantarflexor
moment/ power between taichi group and control group were found during one stepping
down. It mean that two group were similar in frontal plane kinetics. Compared to previous
study (Table 7), our findings were greater. It was because of step height (20cm vs. 15cm)
and different experimental design. In order to close to the actual diary situation, stair
descent then down to ground would be further investigated.
Our findings indicated similar hip and knee moments contributions (Costigan et al., 2002;
Nadeau et al., 2003; Novak and Brouwer, 2010), and all of frontal lower limb joints power
presented negative referred absorbing energy.
CONCLUSION: In summary, the present study shows that Taichi would better ability to
translate to forward movement (hip moment/power), to control body (knee moment /power)
and to absorption energy (ankle moment / power) in sagittal plane. Frontal plane kinetics
represented similar between two groups.
REFERENCES:
Beaulieu, F. G., Pelland, L., & Robertson, D. G. E. (2008). Kinetic analysis of forwards and backwards
stair descent. Gait and Posture, 27, 564-571.
Bento, P. C. B., Pereira, G., Ugrinowitsch, C., & Rodacki, A. L. F. (2010). Peak torque and rate of
torque development in elderly with and without fall history. Clinica l Biomechanics, 25, 450-454.
Christina KA and Cavanagh PR (2002). Ground reaction forces and frictional demands during stair
descent: effects of age and illumination. Gait and Posture, 15, 153-158.
Costigan, P. A., Deluzio, K. J., and Wyss U. P. (2002). Knee and hip kinetics during normal stair
climbing. Gait and Posture, 16, 31-37.
Dieën, J. H., & Pijnappels, M. (2009). Effects of conflicting constraints and age on strategy choice in
stepping down during gait. Gait & Posture, 29, 343-345.
Dieën, J. H., Spanjaard, M., Konemann, R., Bron, L., & Pijnappels, M. (2007). Balance control in
stepping down expected and unexpected level changes. Journal of Biomechanics, 40, 3641-3649.
Lark SD, Buckley JG, Jones DA, and Sargeant AJ (2004) European Journal of Applied Physiology,
91:287-295.
Nadeau, S., McFadyen, B. J., and Malouim, F. (2003). Frontal and sagittal plane analyses of the stair
climbing task in healthy adults aged over 40 years: what are the challenges compared to level walking?
Clinical Biomechanics, 18, 950-959.
Novak, A. C., & Brouwer, B. (2010). Sagittal and frontal lower limb joint moments during stair ascent
and descent in young and older adults. Gait & Posture. doi:10.1016/j.gaitpost.2010.09.024
Protopapadaki A, Drechsler WI, Cramp MC, Coutts FJ, and Scott OM (2007) Clinical Biomechanics,
22:203-210.
Reeves, N. D., Spanjaard, M., Mohagheghi, A. A., Baltzopoulos, V., & Maganaris, C. N. (2008).
Influence of light handrail use on the biomechanics of stair negotiation in old age. Gait & Posture, 28,
327-336.
Riener, R., Rabuffetti, M., & Frigo, C. (2002). Stair ascent and descent at different inclinations. Gait &
Posture, 15, 32-44.
Salsich, G. B., Brechter, J. H., and Powers C. M. (2001). Lower extremity kinetics during stair
ambulation in patients with and without patellofemoral pain. Clinical Biomechanics, 16, 906-912.
Table 7
Front peak lower limb joint moments compared to previous study
Peak moment (Nm/kg)
Hip Abductor
Knee Abductor
Ankle Invertor
Novak and Brouwer (2010)
0.74
0.39
0.12
present study (taichi)
0.97
0.41
0.36
present study (control)
0.99
0.42
0.43
Frontal plane: No significant differences in hip abductor/ knee abductor/ ankle plantarflexor
moment/ power between taichi group and control group were found during one stepping
down. It mean that two group were similar in frontal plane kinetics. Compared to previous
study (Table 7), our results were larger. It was because of step height (20cm vs. 15cm) and
different experimental design. In order to close to the actual diary situation, stair descent
then down to ground would be further investigated.
Our findings indicated similar hip and knee moments contributions (Costigan et al., 2002;
Nadeau et al., 2003; Novak and Brouwer, 2010), and all of frontal lower limb joints power
presented negative referred absorbing energy.
CONCLUSION: In summary, the present study shows that Taichi would better ability to
translate to forward movement (hip moment/power), to control body (knee moment /power)
and to absorption energy (ankle moment / power) in sagittal plane. Frontal plane kinetics
represented similar between two groups.
REFERENCES:
Beaulieu, F. G., Pelland, L., & Robertson, D. G. E. (2008). Kinetic analysis of forwards and backwards
stair descent. Gait and Posture, 27, 564-571.
Bento, P. C. B., Pereira, G., Ugrinowitsch, C., & Rodacki, A. L. F. (2010). Peak torque and rate of
torque development in elderly with and without fall history. Clinical Biomechanics, 25, 450-454.
Christina KA and Cavanagh PR (2002). Ground reaction forces and frictional demands during stair
descent: effects of age and illumination. Gait and Posture, 15, 153-158.
Costigan, P. A., Deluzio, K. J., and Wyss U. P. (2002). Knee and hip kinetics during normal stair
climbing. Gait and Posture, 16, 31-37.
Dieën, J. H., & Pijnappels, M. (2009). Effects of conflicting constraints and age on strategy choice in
stepping down during gait. Gait & Posture, 29, 343-345.
Dieën, J. H., Spanjaard, M., Konemann, R., Bron, L., & Pijnappels, M. (2007). Balance control in
stepping down expected and unexpected level changes. Journal of Biomechanics, 40, 3641-3649.
Lark SD, Buckley JG, Jones DA, and Sargeant AJ (2004) European Journal of Applied Physiology,
91:287-295.
Nadeau, S., McFadyen, B. J., and Malouim, F. (2003). Frontal and sagittal plane analyses of the stair
climbing task in healthy adults aged over 40 years: what are the challenges compared to level walking?
Clinical Biomechanics, 18, 950-959.
Novak, A. C., & Brouwer, B. (2010). Sagittal and frontal lower limb joint moments during stair ascent
and descent in young and older adults. Gait & Posture. doi:10.1016/j.gaitpost.2010.09.024
Protopapadaki A, Drechsler WI, Cramp MC, Coutts FJ, and Scott OM (2007) Clinical Biomechanics,
22:203-210.
Reeves, N. D., Spanjaard, M., Mohagheghi, A. A., Baltzopoulos, V., & Maganaris, C. N. (2008).
Influence of light handrail use on the biomechanics of stair negotiation in old age. Gait & Posture, 28,
327-336.
Riener, R., Rabuffetti, M., & Frigo, C. (2002). Stair ascent and descent at different inclinations. Gait &
Posture, 15, 32-44.
Salsich, G. B., Brechter, J. H., and Powers C. M. (2001). Lower extremity kinetics during stair
ambulation in patients with and without patellofemoral pain. Clinical Biomechanics, 16, 906-912.