Comparison of gait of young men and elderly men.

Comparison of Gait of Young Men and Elderly Men Elderly people frequently use physical therapy services to achieve their maximal functional ability in motor activities such as gait. Clinicians are interested in the normal gait characteristics of all age groups, especially the elderly population.

Changes in walking patterns have been reported as early as 60 years of age. [1,2] Murray et al found that timing and stride dimensions were not systematically related to age in their gait study of 60 men aged 20 to 65 years; however, the subjects 60 to 65 years of age differed from the younger subjects in that they demonstrated shorter step lengths and stride lengths, decreased ankle extension, and decreased pelvic rotation. [2] A gait analysis of 64 men aged 20 to 87 years divided into eight age groups revealed differences in the gait characteristics of stride length, cadence, vertical oscillation of the head, and movements of the shoulders and ankles in the three groups of men over 65 years of age when compared with the younger groups of men during free-speed gait. [3]

Gabell and Nayak found no significant differences between 32 healthy elderly adults (aged 61-87 years) and 32 healthy adults (aged 21-47 years) in their gait analysis of intercycle variability of stride time, step length, and stride length. [4]

Several investigations and reports analyzed the gait characteristics of healthy men within a broad span of ages, including the elderly, to determine ranges of values for gait characteristics, [5,6] establish relationships of gait characteristics with speed, [7,8] or compare the gait characteristics of healthy men with male populations with pathological conditions. [9] These investigations, however, did not directly compare gait characteristics between the young and elderly men.

Differences observed in the gait characteristics of elderly men when compared with young men were similar to those found in gait characteristics of elderly women when compared with young women. [10] Analysis of the gait patterns of men separate from our previous comparison of gait characteristics between matched groups of healthy elderly women and healthy young women is necessary because physiological differences have been documented between the sexes. [11]

Because few studies have investigated the differences between healthy elderly men and healthy young men, additional comparisons are needed. Previous studies attempted to compare groups of men who were similar in height and weight, although specific matching of subjects between groups was not completed. [2,3]

Based on the results of previous research, we hypothesized that a significant difference would exist between the healthy young and healthy elderly groups on eight gait characteristics. The purpose of this study was to describe and compare the free-speed gait characteristics of matched groups of healthy elderly men and healthy young men.

Method

Subjects and Selection Procedure

Twenty-four male volunteers, 12 between 20 and 32 years of age and 12 between 60 and 74 years of age, were accepted as subjects in this study. Each subject provided his informed consent in accordance with the procedures of the University of Nebraska Institutional Review Board.

All of the subject were found to be free of disabling physical conditions or minor ailments that could affect or influence locomotion based on a medical review and an objective examination by a licensed physical therapist. Specifically, the subjects were without musculoskeletal or neurological involvement or medication for these conditions.

One tester (PAH) took all measurements. Height and mass were measured to provide descriptive characteristics for the groups. An average of three independent measurements was used to determine values for leg length and for skinfold thickness, which were used to determine the percentage of body fat. Leg lengths were measured to ensure that each subject was without a leg-length discrepancy ([+ or -] 1.9 cm) as defined by Subotnick. [12] This criterion is important because leg length is a major determinant of stride length. [13]

The percentage of body fat of each subject was determined using skinfold measurements to ensure that no subjects who were extremely lean or obese would be included in the study. Percentage of body fat for the young male subjects was calculated using the age-specific formula of Jackson and Pollock. [14] All young male subjects were within one standard deviation of the average percentage of body fat (13.4% [+ or -] 6.0%) for 18- to 24-year-old men as reported by Jackson and Pollock. [15] Subjects 60 years of age or older also were within one standard deviation of their age-specific average percentage of body fat (22.6% [+ or -] 4.1%). [16]

The elderly men meeting these criteria were tested first. Young men meeting these criteria were recruited to match the elderly men on the basis of right-leg length. The matching of right-leg lengths was within the same range suggested by Subotnick [12] for leg-length discrepancies to achieve a close pairing of subjects between the young and elderly groups.

Instrumentation

Data collection consisted of high-speed cinematography resuling in synchronized front and side views of each subject's free-speed gait down a 14-m walkway. The instrumentaion, gait laboratory, and measurement methods for analysis have been described in detail previously. [10,17,18])

The front camera was a Photec IV (*1) fitted with a 50-mm Nikon lens set 15.6 m from the walkway. The side camera, a LoCam (*3) fitted with a 25-mm Cosmicar lens, (*3) was positioned 8 m from the center of the walkway. Both cameras were set to run at 100 frames per second. A 1-m reference scale and a lighting device were placed in the view of both cameras to provide a common reference for distance and for synchronizing front and side film frames during the film analysis.

The processed film was displayed on a Lafayette Dataviewer (*4) rear-projection system. The desired measurements were made directly from the projected image. A Numonics digitizer (*5) was used in conjunction with the projection system to assign separate X,Y-coordinate values for any landmark from both front- and side-view films. The coordinate values for the landmarks were stored in a computer (*6) and used for calculating the variables.

The procedure described by Sutherland and Hagy [17] and validated in 1980 by Sutherland et al [18] was followed in this study to obtain the measurements with the processed film. Reliability of the measurements taken from our processed film was high when test-retest results were compared during a pilot study. The same observer (PAH) made all of the test-retest measurements from the film, recording a maximum deviation of 2.5 degrees for rotational measurements and a maximum deviation of 2 cm for distance measurements.

Gait variables measured from the side view included ankle plantar-flexion and dorsiflexion range of motion, velocity, step length, stride length, and vertical excursion of the center of gravity. The front-view camera provided the data for determining stride width, lateral center-of-gravity excursion, and pelvic obliquity.

Procedure

Each subject participated in one 45-minute testing session at the Gait Analysis Laboratory at the University of Nebraska at Omaha. The required dress included shorts and a sleeveless shirt. Tape markers were placed on anatomical points of each subject for easy reference on the processed film. The description and specific placement of the markers have been described previously. [10, 12, 13]

The subjects then walked barefoot along the 14-m walkway. The subjects were requested to walk at what they considered their natural pace when walking down a sidewalk without obstructions. The first 4.75 m of the walkway allowed each subject to accelerate to his chosen walking speed before reaching the filmed area. The area from which measurements were taken was 3.25 m long, allowing one to two gait cycles depending on the size or the subject and his walking speed. The last 6 m of the walkway ensured that each subject did not decelerate until he had left the filming area. Each subject performed three trials.

Data Analysis

Means and standard deviations were calculated for all of the variables. An independent t test was used to compare descriptive characteristics between the groups. Differences in the gait characteristics between the two groups were examined using a correlated t test because the groups were nonrandom and matched for leg length. Significance was accepted at the .01 level.

Results

No significant differences were found between the groups of men for either right or left leg-length comparisons, suggesting that the groups were well matched for leg length. The elderly men had a higher percentage of body fat than the younger men. Both groups, however, were within the normal range for percentage of body fat based on their age ranges. The basic descriptive characteristics of both groups are reported in Table 1.

No significant differences were found between the two groups for all variables measured from the side view, including step length, stride length, ankle ROM, velocity, and vertical center-of-gravity excursion. The gait characteristics from the side view are presented in Table 2.

The elderly men demonstrated a significantly smaller stride width (p [is less than] .01) compared with the young men. No significant differences were found between the groups for lateral excursion of the center of gravity or pelvic obliquity. The values obtained for the gait characteristics measured from the film of the front-view camera are shown in Table 3.

Discussion

This study resulted as a follow-up to a previous study comparing healthy elderly women with healthy young women. Data for the male subjects in this study were compared and analyzed separately from the previous study of women because of the documented physiological differences between the sexes. [11] We were interested in whether the elderly men demonstrated the same changes in gait that were demonstrated by the elderly women. We were also interested in whether the elderly men in our study demonstrated the same changes in gait that were found in elderly men by other authors.

Specific comparison of the results of many previous studies with data from this study is limited because normalization of gait measurements with respect to body size is an unresolved problem in human locomotion research. [13] Matching of the young group with the elderly group in our study using leg-length measurements was considered crucial because of the influence of leg length on stride length. [13]

The values of step length and stride length of the men in our study are much greater than values published in a study in Murray et al [2] involving 60 men aged 20 to 65 years and in a study by Kirtley et al [7] of 10 male subjects 18 to 63 years of age walking at their natural speed. Larsson et al examined the stride length of 32 male and female subjects aged 20 to 70 years during walking speeds classified as "very slow," "slow," "ordinary," "fast," and "very fast." [8] The mean values of stride length from both groups of men in our study are closest to the mean value of stride length in the very fast category (1.93 m) in the Larsson et al study. [8]

Compared with the results of other studies, both groups of men in our study demonstrated very long stride lengths; however, the mean values of velocity for both groups of men in this study were smaller than the mean values of velocity from other studies. [3,7,8] The conflicting results may be attributed to the differences in the population studied or methodologies used for testing. Velocity of walking may result from many combinations of stride length and cadence, explaining the differences found between the studies. High values of stride length reported from our subjects may be a result of longer leg lengths.

The mean velocities of the elderly men and the young men during free-speed ambulation are similar to values published by Katoh et al [9] of 32 male and female subjects ambulating at their chosen natural speed. The velocity values of the men in this study are also similar to the values of 534 men during functional ambulation at locations such as commercial, business, and residential areas. [5] The similarity of results suggests that the men in our study selected a functional walking speed as their natural free-speed gait.

Pelvic obliquity values of the men reported in the literature ranged from 5 to 8 degrees, which is similar to the findings in our study. [3,18] Both groups of men in this study maintained a lateral center-of-gravity excursion within the 5-cm range reported in the literature. [13] The vertical excursion of the center of gravity for both groups of men in this study exceeded this 5-cm range. The long stride lengths in relation to the moderate gait velocities may explain the larger values for vertical center-of-gravity excursions.

Significant differences were observed between the two groups of men in stride width; however, both groups demonstrated great variability in values of stride width. Gabell and Nayak [4] reported similar findings in their study of young subjects (21-47 years of age) and elderly subjects (66-84 years of age) during gait. Variability in values of stride width was also observed in our previous study of healthy elderly and healthy young woemn. [10] Although the younger men in our study demonstrated statistically larger values of stride width than the elderly men, the mean stride-width values from both groups are within the range of 2.5 to 12.7 cm reported in the literature. [3,6]

No significant differences were observed between the two groups in this study for values of ankle movement. Murray et al, however, found slightly less excursion during ankle movement in subjects 60 to 65 years of age. [2] Older men (aged 81-87 years) demonstrated significantly less ankle extension than younger men at the end of stance phase. [3] Research findings of elderly women also showed decreased ankle movement. [10]

Caution is advised when applying the results of this study to other populations because of the differences in subject selection and measuring techniques. A true random sampling of the age groups may not have been represented because of the small sample size. Subjects' motivation and ability to follow instructions may have influenced the results. Despite our adherence to the guidelines established for subject selection, some subjects may have had an undiagnosed or unrecognized pathological condition that affected their gait.

Clinical Implications

This study of the linear and temporal aspects of the gait patterns of healthy young men and healthy elderly men may assist physical therapists who use gait characteristics to evaluate a patient's progress. The degree that a pathological condition would further affect the gait characteristics of both groups is beyond the scope of this study.

The results of this comparison of healthy elderly men with healthy young men contrast with the results of a previous study that used the same methodology and compared matched groups of healthy elderly women with healthy young women. [10] The gait characteristics between the two groups of men did not differ, whereas the healthy elderly women demonstrated a smaller step and stride length, a slower waling speed, less pelvic obliquity, and less ankle movement than the healthy young women. These conflicting results may be attributed to the documented physiological differences between the sexes, [11] suggesting that the aging process affects healthy women differently than healthy men. It is unclear whether physical activity affected the results in both studies. Although the studies of men and women involved healthy subjects, the elderly men were more likely to report participation in vigorous activities (eg, softball and hunting) than the elderly women who participated in an earlier study.

Further study of gait characteristics in the elderly population is needed before definitive conclusions may be made about the effects of aging on gait. Future research could focus on the relationship of physical activity to the gait characteristics observed.

Conclusions

The effects of aging were not observed. The young men and the elderly men did not demonstrate significant differences in seven of the eight gait characteristics examined (ie, step length, stride length, ankle ROM, velocity, vertical and horizontal excursions of the center of gravity, and pelvic obliquity). Although the young men demonstrated significantly larger values in stride width than the elderly men, the values of stride width for both groups were within the range published for the healthy population. The statistically different values were not clinically relevant.

(*1) Photomic Systems, Inc, 265 H Sobrante Way, Sunnyvale, CA 94086.

(*2) Nikon, Inc, 623 Stewart Ave, Garden City, NY 11530.

(*3) Redlake Corp, 1711 Dell Ave, Campbell, CA 95008.

(*4) Lafayette Instrument Co, 3700 Sagamore Pky N, PO Box 5729, Lafayette, IN 47903.

(*5) Numonics Corp, 418 Pierce St, Lansdale, PA 19446.

(*6) Model 4052, Tektronix, Inc, PO Box 500, Beaverton, OR 97077.

References

[1] Berry G, Fisher R, Lang S: Detrimental incidents, including falls, in the elderly institutional population. J AM Geriatr Soc 29: 322-324, 1981

[2] Murray M, Drought B, Ross C, et al: Walking patterns of normal men. J Bone Joint Surg [Am] 46:335-360, 1964

[3] Murray M, Kory R, Clarkson B: Walking patterns in healthy old men. J Gerontol 24:169-178, 1969

[4] Gabell A, Nayak V: The effect of age on variability in gait. J Gerontol 39:662-666, 1984

[5] Finley F, Cody K: Locomotive characteristics of urban pedestrians. Arch Phys Med Rehabil 51: 423-426, 1970

[6] Bampton S: A guide to the Visual Examination of Pathological Gait. Philadelphia, PA, Temple University Press, Rehabilitation Research and Training Center #8, 1979

[7] Kirtley C, Whittle W, Jefferson R: Influence of walking speed on gait parameters J Biomed Eng 7:282-288, 1985

[8] Larsson L, Odenrick P, Sandlund B, et al: The phases of the stride and their interaction in human gait. Scand J Rehabil Med 12:107-112, 1980

[9] Katoh Y, Chao Y, Laughman R, et al: Biomechanical analysis of foot function during gait and clinical applications. Clin Orthop 177: 23-33, 1983

[10] Hageman PA, Blanke DJ: Comparison of gait of young women and elderly women. Phys Ther 66:1382-1387, 1986

[11] McArdle W, Katch K, Katch V: Exercise Physiology: Energy, Nutrition, and Human Performance, ed 3. Philadelphia, PA, Lea & Febiger, 1986

[12] Subotnik S: The short leg syndrome. J Am Podiatr Med Assoc 66:720-723, 1976

[13] Inman V, Ralston H, Todd R: Human Walking. Baltimore, MD, Williams & Wilkins, 1981

[14] Jackson A, Pollock M: Generalized equations for predicting body density in men. Br J Nutr 40: 497-504, 1978

[15] Jackson A, Pollock M: Prediction accuracy of body density, lean body weight, and total body volume equations. Med Sci Sports 9:197-201, 1977

[16] Latin R, Johnson S, Ruhling R: An anthropometric estimate of body composition of older men. J Gerontol 42:24-28, 1987

[17] Sutherland D, Hagy J: Measurement of gait movements from motion picture film. J Bone Joint Surg [Am] 54:787-797, 1972

[18] Sutherland D, Olsen R, Cooper L, et al: The development of mature gait. J Bone Joint Surg [Am] 62:336-353, 1980

D Blanke, Phd, is Associate Professor, Department of Health, Physical Education, and Recreation, University of Nebraska at Omaha, Sixtieth and Dodge St, Omaha, NE 68182.

P Hageman, MS, PT, is Assistant Professor, Division of Physical Therapy Education, School of Allied Health Professions, University of Nebraska Medical Center, 42 and Dewey Ave, Omaha, NE 68105-1065 (USA). Address all correspondence to Mrs Hageman.

This article was submitted February 16, 1988; was with the authors for revision for 12 weeks; and was accepted August 23, 1988.