Evaluation_of_normal_Gait_using_electrogoniometer
- 2. 696 J SCI IND RES VOL 68 AUGUST 2009 Journal of Scientific & Industrial Research Vol. 68, August 2009, pp. 696-698 *Author for correspondence E-mail: neel15278@rediffmail.com Evaluation of normal Gait using electro-goniometer Neelesh Kumar1 , Dinesh Pankaj1 , Ankit Mahajan1 , Amod Kumar1 and B S Sohi2 1 Central Scientific Instruments Organisation (CSIO), Chandigarh 160 030, India 2 University Institute of Engineering & Technology (UIET), Chandigarh 160 014, India Received 23 May 2008; revised 09 April 2009; accepted 22 May 2009 A potentiometer-based electro-goniometer has been developed to measure knee angle of normal healthy individuals (5), who were instructed to walk slow, normal and brisk for walking distance of 17 m. Data acquisition and analysis on acquired data were done using LabVIEW. For individuals with different physical parameters, it was found that frequency (steps/min) remains the same irrespective of varying velocities. Step length reduces as individuals walk without shoes. Keywords: Gait cycle, Goniometer, Knee flexion angle, Step length, Stride length Introduction Quantitative estimation of human walking is normally done through gait analysis, which involves extraction and evaluation of Gait parameters1,2 . Clinical gait analysis allows measurement and assessment of walking biomechanics such as joint motion for identification of abnormal characteristics and recommendation of treatment alternatives3 . Joint mobility can be determined by visual estimation, gyroscope, accelerometers, and goniometers4 . Knee angle measurement using electro-goniometer is used increasingly5 . Studies are available on evaluation of gait parameters during normal walking6,7 . Present study evaluates various spatio temporal parameters of normal walk with developed electro-goniometer. Walking comparison has been made on the basis of subjects age, height, weight, sex etc. Materials and Methods Normal healthy individuals (5, both male/female; age, 21-30 y; weight, 49-72 kg; height, 157-175 cm) were evaluated of gait parameters for prosthetic development. All individuals were free from cardiovascular, orthopedic, clinical pathology affecting their ambulatory capacity, and were comfortably able to walk long distances without any external assistance. Distance covered by uninterrupted walking was 17 m. All individuals were instructed to walk at their normal, slow and fast speed. Five walking trials of each individual, for three self selected walking speeds were conducted. An electro- goniometer sensor using principle of potentiometery was developed to measure angles between two linear elements meeting at a joint. A linear potentiometer (5K) uses a principle of linear change in electrical resistance with linear change in angle of rotation of axis. Electro-goniometer device was connected to human knee joint. Electro- goniometer converts joint angle in to voltage, which is sensed by DAQ card. Maximum sampling rate of DAQ card was 500kS/s and it can digitize analog signals with 12 bit ADC. A suitable calibration factor is derived to calibrate measured knee angle values in terms of acquired voltages. Accuracy and precision of electro-goniometer depends on mechanical design and electrical properties of sensor. Precision achieved was 賊0.5属. Acquired data was stored (rate 1 Hz) and analysed using LabVIEW (version 7.0) for calculation of spatial parameters (flexion angle, step length, forward velocity, cadence etc.). Step length is total distance along path of walk from foot strike of one foot to foot strike of opposite foot. Cadence is defined as the number of steps taken per unit time. Results Variation, reported in walking parameters for the subjects (n=5), is mainly due to physical characteristic
- 3. KUMAR et al: EVALUATION OF NORMAL GAIT USING ELECTRO-GONIOMETER 697 (height, weight & sex) of every individual. The study reveals that cadence of individuals remained almost same in self selected walking speed irrespective of walking patterns. Self-selected speed variation was 3.12-5.46 (slow), 4.12-6.07 (normal) and 5.54-7.59 (fast). Average cadence parameter were evaluated as 99.75 (slow), 120 (normal) and fast (132.45) walk. Knee flexion angle variation is 65属 for slow walk (Fig. 1), 67属 for normal walk (Fig. 2), and 69属 for fast walk (Fig. 3). Experiments were also done to analyze walking patterns of individuals wearing footwear and without footwear. Knee flexion angle varies up to 4属 with increase in walking speed with footwear. Significant increase in step, stride length up to 4 cms was analysed when walking with footwear. Fig. 1Knee angle variation for slow walk Fig. 2Knee angle variation for normal walk 0:00.000 0:05.000 0:10.000 0:15.000 0:20.000 180 -180 -150 -100 -50 (deg) 0 50 100 150 K R O 0:00.000 0:05.000 0:10.000 0:15.000 180 -180 -150 -100 -50 (deg) 0 50 100 150
- 4. 698 J SCI IND RES VOL 68 AUGUST 2009 Similarly, decrease in stride length up to 4 cms was observed in case of walking without footwear. Conclusions Studies on normal gait patterns of healthy individual for different walking speed give ability to diagnose any abnormalities. Experiments prove that changes in gait parameters like linear velocity are dependent on step length and stride length. Range of knee flexion angle for normal walking speed is 65属. Knee flexion angle varies with variation in velocity of walking. Knee flexion angle variation from slow and fast speed is 4属. These finding can be used for developing prosthetic control algorithm to provide swing stance stability based on different walking speeds. Significant increase in step, stride length and decrease in cadence is reported when walking with footwear. Additional weight of footwear adds inertial force during swing phase thus increasing step and stride lengths. References 1 Richard F & Duddley S, Prostheses and artificial limbs, Encycl Appl Phys, 15 (1996) 115-128. 2 Bohannon W R, Comfortable and maximum walking speed of adults aged 20-79 years: reference values and determinants, J Age Ageing, 26 (1997) 15-19. 3 Davis B R, Reflections on clinical gait analysis, J Electromyo Kinesi, 7 (1997) 251-257. 4 Cleffken B, Breukelen G Van, Brink P, Mameren H Van & Damink S O, Digital goniometric measurement of knee joint motion: Evaluation of usefulness for research settings and clinical practice, Knee, 14 (2007) 385-389. 5 Sutherland D.H, The evolution of clinical gait analysis Part II Kinematics, J Gait Posture, 16 (2002) 159-179. 6 Majumdar D, Banerjee P K, Majumdar D, Pal M & Kumar R, Temporal spatial parameters of gait with barefoot, bathroom slippers and military boots, Indian J Physiol Pharmacol, 50 (2006) 33-40. 7 Blanc Y, Balmer C, Landis T & Vingerhoets F, Temporal parameters and patterns of the foot roll over during walking: normative data for healthy adults, J Gait Posture, 10 (1999) 97-108. Fig. 3Knee angle variation for fast walk R T 0:00.000 0:05.000 0:10.000 0:15.000 180 -180 -150 -100 -50 (deg) 0 50 100 150