Calibration of wrist-worn ActiWatch 2 and ActiGraph wGT3X for assessment of physical activity in young adults

Publication date: Available online 19 November 2018

Source: Gait & Posture

Author(s): Paul Lee, C.Y. Tse

Abstract

Background

The validity of Actiwatch 2 in assessing sleep was evident, but its validity in assessing physical activity (PA) level was unknown.

Research question

The objective of this study was to validate the wrist-worn Actiwatch 2 and ActiGraph wGT3X as a measurement of PA level against energy expenditure measured by indirect calorimetry.

Methods

Twenty-seven university students aged 18-26 were recruited from July 2016 to May 2017. They were instructed to run at different speeds (4, 6, 8, 10, and 12 km/h) on a treadmill, each speed for 10 minutes. Oxygen consumption and carbon dioxide production of the subjects was measured by indirect calorimetry using the Cosmed K4b² gas analyzer. Each subjects wore a single pair of accelerometers (Actiwatch 2 and ActiGraph wGT3X) on both wrists.

Results

All the accelerometers were strongly correlated (ρ=0.83-0.94, all p-values <0.001), and all four accelerometers were strongly correlated with the METs obtained from the Cosmed K4b² (ρ=0.72-0.74, all p-values <0.001). Regression analysis showed that the non-dominant wrist-worn Actiwatch 2 cutoff cpm for moderate and vigorous PA were 399 and 1,404, respectively; for the ActiGraph wGT3X-BT the corresponding cutoffs were 4,514 and 15,044, respectively. The goodness-of-fit of the MET prediction equations were all >75%. When classifying the activities as either sedentary, light activity, moderate-intensity activity, or vigorous-intensity activity using the MET prediction equations, the agreements between the four accelerometers and that by the Cosmed K4b² were high, all AUCs were above 80% except those of the Actiwatch worn on the left (non-dominant) wrist. The Bland-Altman plots show that, for all four accelerometers, the biases were close to zero and error variances were largest when the mean measurements were around 6 METs.

Significance

We showed that wrist-worn Actiwatch 2 and ActiGraph wGT3X-BT were strongly correlated in PA assessment.

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Kinematics and shock attenuation during a prolonged run on the athletic track as measured with Inertial Magnetic Measurement Units

Publication date: Available online 19 November 2018

Source: Gait & Posture

Author(s): Jasper Reenalda, Erik Maartens, Jaap H. Buurke, Allison H. Gruber

Abstract

Background

Tibial stress fractures are common running related injury and their etiology may include biomechanical factors like impact forces, shock attenuation, lower limb kinematics and how these factors are influenced by intense or prolonged running. Inertial-magnetic measurement units (IMUs) have recently emerged as an alternative to motion capture but their use to date was mostly limited to segmental and joint motion.

Research question

The present study sought to examine the effects of a prolonged run on shock attenuation, peak tibial and sacral acceleration (PTA, PSA), and lower limb kinematics using IMUs.Methods: Ten trained male runners (31 +/−5 yr, 183 +/- 3 cm, 76 +/- 9 kg) performed a twenty-minute prolonged run on an athletic track at estimated lactate threshold speed. Eight IMUs, positioned over the feet, lower and uppers legs, sacrum and sternum, were used to calculate joint kinematics, impact parameters and shock attenuation in the time domain (1-(PSA/PTA)*100).

Results

PTA increased while PSA and shock attenuation did not change following the prolonged run. Hip and knee flexion at midstance decreased. Vertical lower leg angle at initial contact did not change.

Conclusion

By using IMUs, it was shown that a prolonged run at estimated lactate threshold speed had significant effects on kinematics and tibial acceleration parameters. By modifying hip and knee joint kinematics during stance, the body was able to maintain sacral acceleration possibly by shifting from active shock attenuation to more passive mechanisms.

Significance

The present study shows that inertial sensors can be used in outdoor running to measure joint kinematics and kinetic parameters like PTA, PSA and shock attenuation simultaneously. The results of this study show new insights into how the body copes with impact during prolonged running.

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Walking on a treadmill improves the stride length-cadence relationship in individuals with Parkinson’s disease

Publication date: Available online 19 November 2018

Source: Gait & Posture

Author(s): M. Ambrus, J.A. Sanchez, M. Fernandez-del-Olmo

Abstract

Background

The gait pattern in Parkinson´s disease (PD) is characterized by a deficit in the internal regulation of stride length (SL), while the control of cadence (Cad) remains intact. The use of the treadmill as a gait rehabilitation tool has provided novel options for treatment of gait impairments in PD. However, it remains unclear whether walking on the treadmill changes the stride length–cadence relationship (SLCrel) in PD. The purpose of the present study was to analyze the SLCrel in PD subjects walking on a treadmill vs. overground, and to further compare the SLCrel to that of age-matched healthy subjects.

Methods

Fifteen PD subjects and fifteen age-matched controls walked overground and on a treadmill at five different self-selected speeds. Gait speed, SL and Cad were recorded at each self-selected speed. A linear regression analysis was conducted to explore the SLCrel and to determine the slope and intercept for each participant.

Results

PD subjects showed a lower intercept than control subjects when walking both overground and on a treadmill (F = 8.51, p = 0.007). In comparison with walking overground, walking on a treadmill resulted in a significant increase in the intercept in both PD and control groups (F = 12.17, p = 0.002). There were no significant differences in the slope of the SLCrel.

Conclusion

PD subjects are able to improve the internal regulation of SL when walking on a treadmill. Our results confirm the potential therapeutic effects of treadmill training for gait rehabilitation in PD and suggest that the mechanisms underlying the positive effects of treadmill training on PD subjects are sustained.

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Calibration of wrist-worn ActiWatch 2 and ActiGraph wGT3X for assessment of physical activity in young adults

Publication date: Available online 19 November 2018

Source: Gait & Posture

Author(s): Paul Lee, C.Y. Tse

Abstract

Background

The validity of Actiwatch 2 in assessing sleep was evident, but its validity in assessing physical activity (PA) level was unknown.

Research question

The objective of this study was to validate the wrist-worn Actiwatch 2 and ActiGraph wGT3X as a measurement of PA level against energy expenditure measured by indirect calorimetry.

Methods

Twenty-seven university students aged 18-26 were recruited from July 2016 to May 2017. They were instructed to run at different speeds (4, 6, 8, 10, and 12 km/h) on a treadmill, each speed for 10 minutes. Oxygen consumption and carbon dioxide production of the subjects was measured by indirect calorimetry using the Cosmed K4b² gas analyzer. Each subjects wore a single pair of accelerometers (Actiwatch 2 and ActiGraph wGT3X) on both wrists.

Results

All the accelerometers were strongly correlated (ρ=0.83-0.94, all p-values <0.001), and all four accelerometers were strongly correlated with the METs obtained from the Cosmed K4b² (ρ=0.72-0.74, all p-values <0.001). Regression analysis showed that the non-dominant wrist-worn Actiwatch 2 cutoff cpm for moderate and vigorous PA were 399 and 1,404, respectively; for the ActiGraph wGT3X-BT the corresponding cutoffs were 4,514 and 15,044, respectively. The goodness-of-fit of the MET prediction equations were all >75%. When classifying the activities as either sedentary, light activity, moderate-intensity activity, or vigorous-intensity activity using the MET prediction equations, the agreements between the four accelerometers and that by the Cosmed K4b² were high, all AUCs were above 80% except those of the Actiwatch worn on the left (non-dominant) wrist. The Bland-Altman plots show that, for all four accelerometers, the biases were close to zero and error variances were largest when the mean measurements were around 6 METs.

Significance

We showed that wrist-worn Actiwatch 2 and ActiGraph wGT3X-BT were strongly correlated in PA assessment.

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Kinematics and shock attenuation during a prolonged run on the athletic track as measured with Inertial Magnetic Measurement Units

Publication date: Available online 19 November 2018

Source: Gait & Posture

Author(s): Jasper Reenalda, Erik Maartens, Jaap H. Buurke, Allison H. Gruber

Abstract

Background

Tibial stress fractures are common running related injury and their etiology may include biomechanical factors like impact forces, shock attenuation, lower limb kinematics and how these factors are influenced by intense or prolonged running. Inertial-magnetic measurement units (IMUs) have recently emerged as an alternative to motion capture but their use to date was mostly limited to segmental and joint motion.

Research question

The present study sought to examine the effects of a prolonged run on shock attenuation, peak tibial and sacral acceleration (PTA, PSA), and lower limb kinematics using IMUs.Methods: Ten trained male runners (31 +/−5 yr, 183 +/- 3 cm, 76 +/- 9 kg) performed a twenty-minute prolonged run on an athletic track at estimated lactate threshold speed. Eight IMUs, positioned over the feet, lower and uppers legs, sacrum and sternum, were used to calculate joint kinematics, impact parameters and shock attenuation in the time domain (1-(PSA/PTA)*100).

Results

PTA increased while PSA and shock attenuation did not change following the prolonged run. Hip and knee flexion at midstance decreased. Vertical lower leg angle at initial contact did not change.

Conclusion

By using IMUs, it was shown that a prolonged run at estimated lactate threshold speed had significant effects on kinematics and tibial acceleration parameters. By modifying hip and knee joint kinematics during stance, the body was able to maintain sacral acceleration possibly by shifting from active shock attenuation to more passive mechanisms.

Significance

The present study shows that inertial sensors can be used in outdoor running to measure joint kinematics and kinetic parameters like PTA, PSA and shock attenuation simultaneously. The results of this study show new insights into how the body copes with impact during prolonged running.

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via IFTTT

Walking on a treadmill improves the stride length-cadence relationship in individuals with Parkinson’s disease

Publication date: Available online 19 November 2018

Source: Gait & Posture

Author(s): M. Ambrus, J.A. Sanchez, M. Fernandez-del-Olmo

Abstract

Background

The gait pattern in Parkinson´s disease (PD) is characterized by a deficit in the internal regulation of stride length (SL), while the control of cadence (Cad) remains intact. The use of the treadmill as a gait rehabilitation tool has provided novel options for treatment of gait impairments in PD. However, it remains unclear whether walking on the treadmill changes the stride length–cadence relationship (SLCrel) in PD. The purpose of the present study was to analyze the SLCrel in PD subjects walking on a treadmill vs. overground, and to further compare the SLCrel to that of age-matched healthy subjects.

Methods

Fifteen PD subjects and fifteen age-matched controls walked overground and on a treadmill at five different self-selected speeds. Gait speed, SL and Cad were recorded at each self-selected speed. A linear regression analysis was conducted to explore the SLCrel and to determine the slope and intercept for each participant.

Results

PD subjects showed a lower intercept than control subjects when walking both overground and on a treadmill (F = 8.51, p = 0.007). In comparison with walking overground, walking on a treadmill resulted in a significant increase in the intercept in both PD and control groups (F = 12.17, p = 0.002). There were no significant differences in the slope of the SLCrel.

Conclusion

PD subjects are able to improve the internal regulation of SL when walking on a treadmill. Our results confirm the potential therapeutic effects of treadmill training for gait rehabilitation in PD and suggest that the mechanisms underlying the positive effects of treadmill training on PD subjects are sustained.

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