Spinal lexibility and Individual actor That Influence It ICHELE C. BATTI'E, STANLEY J. BIGOS, ANN SHEEHY, and ARK D. WORTLEY We conducted an invetigation to examine the pinal flexibility of a large, adult population and to tudy the effect of other individual phyical characteritic on pinal range of motion. The tudy group conited of 3,020 blue collar employee (2,350 men and 670 women) who underwent a phyical examination that included aement of tanding and itting height, weight, houlder flexibility, and pinal flexibility in the agittal and frontal plane. lexibility meaure were correlated poitively to one another; however, lumboacral flexion meaurement aeed by the modified Schober method correlated to the other flexibility meaurement to a much leer degree. Age, ex, and height affected RO, a did obeity and the ratio of tanding height to itting height. The tudy finding indicate that pinal RO cover a wide pectrum of value and i affected by many individual factor. Any attempt to determine what i normal, exceive, or diminihed mut take into account variation caued by age, ex, and other phyical attribute. Key Word: Lumbar region, Phyical therapy, Spine. uch attention ha been given to flexibility of the lumbar pine and it relationhip to back health. Exercie to tretch the back often are advocated in routine daily exercie program for athlete and employee. 1 urthermore, pinalflexibilityha been aumed to be uch an important part of good back health that flexibility meaure have been propoed for ue in preplacement phyical examination and preemployment creening in an effort to identify individual thought to be at greatet rik for developing back problem. Spinal range-of-motion meaurement are a tandard part of the evaluation of patient with back pain, with the mot commonly aeed movement beingflexion. 2 urthermore, uch meaurement are ued extenively in the evaluation of permanent impairment in. Batti'e i a reearch cientit, Department of Orthopaedic, RK-10, Univerity of Wahington, Seattle, WA 98195 (USA). Dr. Bigo i Aitant Profeor, Department of Orthopaedic, Univerity of Wahington.. Sheehy i a predoctoral reearch aociate, Department of Statitic, Univerity of Wahington. r. Wortley i Southern Diviion Rehabilitation Coordinator, Care Enterprie, Orange, CA 92668. Thi tudy wa upported in part by National Intitute for Occupational Safety Health, Grant 5 R010H00982-03, and the Boeing Company. Thi article wa ubmitted October 7, 1985; wa with the author for reviion 16 week; and wa accepted July 10, 1986. Potential Conflict of Interet: 4. individual with longtanding back problem. 3 The finding of uch evaluation then are ued a the bai for deciion regarding diability and compenation. In addition, many exercie and manual therapy technique are ued by patient with back pain to increae backflexibilitywith the hope of decreaing ymptom and peeding recovery. Numerou technique have been developed to ae pinal flexibility. ingertip-to-floor ditance and it-andreach meaurement have been obtained. 4,5 Skin ditraction tet uch a the tandard or modified Schober method alo have been ued. 6 Even ubjective report obtained through quetionnaire have been ued to compile flexibility information. 7 In addition to the ue of tandard goniometer, device uch a inclinometer and pondylometer have been developed for pinal flexibility meaurement. 8-11 Two- and three-dimenional roentgenogram analye have been ued in both reearch and clinical etting. 12-14 lexibility even ha been tudied by variou in vitro mean. 15 or pinalflexibilitymeaurement to be meaningful to clinician or reearcher, they mut have normative information and an undertanding of how different variable affect RO. The purpoe of our invetigation wa to examine the pinal flexibility of a large, adult population to etablih normative value for the meaure ued. In addition, we wanted to determine whether any individual characteritic affect flexibility. Thu, the flexibility meaurement were compared with other individual phyical characteritic to gain a better undertanding of how uch factor affect pinal RO. ETHOD Subject All blue collar employee receiving hourly wage at a Northwet aircraft manufacturing plant were given the opportunity to participate in our tudy. The employee who volunteered to participate in the tudy received no financial remuneration, but the tudy examination were conducted at variou time during their working hour. The 3,020 ubject who participated in the tudy repreented 75% of all employee olicited. The tudy group included 2,350 men and 670 women between the age of 21 and 67 year (Tab. 1). No individual who volunteered to participate were excluded from the tudy for any reaon. After informed conent wa obtained from the volunteer, each ubject wa given a phyical examination by one of three phyical therapit. Volume 67 / Number 5, ay 1987 653
ig. 1. arking and initial poition for the modified Schober method are on the left. The final poition from which the meaurement i obtained i on the right. Procedure The examination of each ubject included aement of tanding height, itting height, weight, houlder flexibility, and pinalflexibilityin the agittal and frontal plane. Becaue of time contraint and the implicity of the tet, each meaurement wa obtained only once. A modified Schober tet wa ued to meaure lumbarflexion.6the tet wa choen for it implicity and becaue of it high correlation with forward flexion meaurement of the lumboacral pine obtained through radiograph (r =.97) a reported by acrae and Wright.6 The modified Schober method require only a platic tape meaure and pen to make three marking on the kin overlaying the lumboacral pine. With the ubject tanding erect, the firt mark i placed at the lumboacral junction, a indicated by the dimple of Venu. A econd mark i placed 5 cm below the lumboacral junction, and a third 10 cm above the junction. The ubject then i aked to bend foward a far a poible, a though to touch the toe, and the new ditance between mark two and three i meaured. Lumbarflexioni expreed a the difference between thi meaurement and the initial ditance of 15 cm (ig. 1). Error in identifying the lumboacral junction of up to 2 cm reult in an error of only a few degree, a compared with flexion meaurement obtained radiographically.6 654 TABLE 1 Study Group Profile Age Group (yr) en (n) Women (n) 20-29 30-39 40-49 50-59 60+ 763 694 480 326 87 168 192 158 125 27 Otherflexibilitytet were choen for their eae of application and popularity in variou clinical etting. Sit-and-reach meaurement were obtained to ae overall flexibility in forward flexion, with meaurement recorded a the ditance (in centimeter) between the fingertip and the toe. The ubject' knee were traight throughout the tet, and the ankle were maintained at 90 degree by having the ole of the feet preed againt a board placed perpendicular to the itting urface. During the teting, lateral flexion wa examined by recording the difference between the poition of thefingertipin erect tanding and in maximal ide bending to the right and left ide. The ubject wa intructed to keep the knee traight and both heel on the floor when bending to the ide. Shoulderflexibilitywa aeed by having the ubject lie prone with the arm tretched overhead while holding onto a wand. The ubject then wa aked to raie the wand a high a poible off the mat without bending the elbow or lift- ing the chin off the mat. The ditance (in centimeter) from the mat to the highet point that the wand wa raied then wa meaured. Data Analyi Data analyi included graphing the data in the form of hitogram, catter plot, and box plot to depict more clearly the general ditribution. We then tabulated the data, orting the different RO data by age and ex and uing the mean and tandard deviation a ummary tatitic. Thee tabulation were ued to ait in the election of variable to be included in the analye of covariance (ANCOVA) for each of the flexibility meaure.16 In each ANCOVA, a flexibility meaure wa the dependent variable, and variable uch a age, ex, height, and weight were ued a independent variable. Our goal when analyzing the data wa to develop a regreion model for each of the flexibility meaure that would permit determination of the effect of variable uch a age, ex, weight, or height onflexibility.when tudying the effect of age, individual were categorized by age group, for example, 20 to 29 year or 30 to 39 year. The effect of age then wa modeled a a trend effect, uch that ubject in the 20- to 29-yearold age group were given the value 1 for age, and thoe in the combined 50+ age group were given the value 4. Thi new variable wa included a a dependent PHYSICAL THERAPY
RESEARCH TABLE 2 ean and Standard Deviation a of lexibility eaurement by General Age Group Age Group (yr) Sex n odified Schober Sit and Reach Side Bending (Right) Side Bending (Left) Shoulder Lift 20-29 30-39 40-49 50-59 60+ 763 168 694 192 480 158 326 125 87 27 7.26 6.47 7.29 6.26 6.90 6.03 6.36 6.19 6.22 6.05 1.58 1.28 1.19 1.25 1.6 2.8 2.17 1.3 1.32 1.2 2.10 2.89-0.48 2.40-3.49 1.45-7.43-0.39-8.98-3.52 8.8 8.1 9.0 7.9 9.2 8.7 9.3 8.2 10.3 7.87 23.39 22.79 21.89 21.66 19.82 19.11 17.75 18.74 17.82 16.95 3.89 3.84 3.6 3.3 3.6 3.4 3.4 3.14 3.78 4.42 23.55 23.18 22.06 21.67 20.07 19.32 17.95 18.69 17.74 17.52 4.0 3.8 3.79 3.3 3.79 3.48 3.56 3.24 3.55 4.52 32.61 30.24 29.77 27.72 24.90 23.81 20.71 19.96 18.25 16.36 11.3 10.2 11.04 11.9 10.4 8.7 10.3 9.1 9.6 12.5 a All meaurement are in centimeter. variable in the ANCOVA. The AN- COVA allow for the control of other variable that may be aociated with the pecific variable under tudy. Thu, the true effect of the variable of interet on RO i determined more preciely, and confounding factor are minimized. RESULTS The mean and tandard deviation for the variou flexibility meaure by age group and ex are hown in Table 2. The trend and ditribution of the four flexibility meaure, with median and range, are diplayed in igure 2 through 5. All flexibility meaure were correlated poitively to one another; the degree of flexibility a aeed by one meaure uually wa imilar to thoe aeed by the other meaure. Correlation coefficient ranged from.38 to.44 when comparing it-and-reach, lateral flexion, and houlder flexibility meaurement to one another. Becaue right and left ide-bending core were imilar within individual (r =.88), an average of the two meaurement wa ued for further analye. The modified Schober method wa unique in that it howed little relationhip to the other flexibility meaure with correlation coefficient of.15 to.24, indicating that it may be meauring a different component of flexibility. A principal component analyi further demontrated that the modified Schober method wa explaining a different component of the variability in the flexibility meaurement than the other meaure. 16 The ANCOVA demontrated that the additional phyical attribute alo were related to the flexibility meaure. With age and ex controlled, height wa related ignificantly to ide-bending, it- ig. 2. ig, 3. Range of houlder flexibility meaurement by age and ex. Range of it-and-reach meaurement by age and ex. Volume 67 / Number 5, ay 1987 655
Uing a regreion model, for example, the it-and-reach meaurement in the 20- to 29-year-old age group wa 1.72 cm le for women than for men. In the combined 50+ age group, however, the meaurement wa 6.21 cm greater for women than for men (ig. 7). The mean ide-bending meaurement decreaed by 2.0 cm for every 10-year increae in age for both exe. ig. 4. ig. 5. Range of modified Schober meaurement by age and ex. Range of average ide-bending meaurement by age and ex. and-reach, and modified Schober meaurement. The regreion model how that for every increae in height by one tandard deviation, the average idebending meaurement increaed by 1.8 cm, the average it-and-reach meaurement decreaed by 2.4 cm, and the average modified Schober meaurement increaed by 0.6 cm. The ratio of tanding height to itting height alo wa examined. or every increae of one tandard deviation in the ratio of itting height to tanding height, decreae of 0.44 and 1.35 cm were etimated in the average ide-bending and it-and-reach meaurement, repectively. Obeity (defined a weight/height 3 ) alo wa related ignificantly to the flexibility meaurement. or every increae in obeity by one tandard deviation (calculated by uing logarithm), increae of 0.4 and 1.0 cm were etimated in the modified Schober and it-andreach meaurement, repectively. After controlling for all of the additional phyical variable examined, we tudied the relationhip between RO and the variable of age and ex. An intereting finding with regard to flexibility and aging wa that a difference in the effect of aging appeared to exit between the exe; the rate of decreae in pinal flexion, a meaured through the modified Schober (ig. 6) and the it-and-reach technique, wa ignificantly le for women than for men. DISCUSSION Pat tudie have agreed that a general decreae in pinal RO occur in aging adult. 5,13,17,18 any conflicting report exit, however, regarding the importance of other factor in relation to flexibility. any author have found difference between the exe, with mot reporting higher pinalflexibilityvalue for men than for women, particularly in the agittal plane. 5,13,17,18 Other report no ignificant ex difference. 10,13 Our tudy demontrated a decided effect of ex on RO, even when controlling for other factor affecting RO. urthermore, a difference in the effect of aging wa demontrated between the exe. Troup et alfirtintimated thi difference when they found lumbar RO decreaed ignificantly in men but not in women in a group of 230 ubject. 18 acrae and Wright imilarly reported that a decreae in agittal mobility of the pine tended to be le in women than in men. 6 The additional variable of tanding height, ratio of tanding height to itting height, and obeity previouly had not been tudied extenively and were hown to have a ignificant effect on flexibility in the agittal plane. Thee relationhip cannot be explained eaily, with the exception of the tanding-toitting height ratio and the it-and-reach tet. Regarding the ratio of tanding height to itting height, individual with longer rather than horter than average trunk for their height may have le difficulty reaching their toe, thu achieving a greater it-and-reach meaurement. Another finding of clinical and reearch importance wa that lumbar RO, a meaured through the modified Schober method, bore little relation to the outcome of the it-and-reach tet. Thi finding add further upport to the idea that it-and-reach, fingertip-tofloor, and other general meaure of forward flexion are not adequate expreion of pinal flexibility. Conidering 656 PHYSICAL THERAPY
ig. 6. Trend in mean modified Schober meaurement with age. RESEARCH might be how they relate to back health, or more pecifically how pinal flexibility relate to the rik for back problem or the recovery from them. When reviewing the cientific literature, little evidence exit to upport the ue of exercie to maintain or increae pinal RO a a protective meaure againt back problem, depite their popularity. Biering-Sorenen examined pinalflexibilityin a large group of individual, following them for one year for ubequent back injurie. He reported that men who experienced an epiode of back pain had ignificantly greaterflexibilitythan thoe who did not experience back pain. 5 Similarly, Howell found the incidence of low back pain wa higher in elite women rower who tretched their back regularly than in thoe rower who did not tretch their back. A ignificant correlation alo exit between hyperflexion and an increaed incidence of back pain. 4 Report on tudie examining the relationhip between pinal mobility and a hitory of back pain have been varied. Some reearcher have reported a general decreae in pinal mobility aociated with a hitory of back problem, 5,8 wherea other have reported the oppoite of increaed pinal mobility. 19 Other report that a hitory of incapacitating back pain had no effect on pinal RO. 13 Longitudinal tudie aeing premorbid pinalflexibilityare needed to define clearly the relationhip between pinal flexibility and back problem. Only then will we know how to ue fully the information provided by our tudy. ig. 7. Trend in mean it-and-reach meaurement with age. CONCLUSION that thee meaure are ued currently at leat a often a more pecific method to examine overall lumbar mobility, uch meaure likely reflect mobility at the hip rather than at the pine. 5 Similar to earlier tudie, 13,15 our reult indicate that RO in the variou age and ex group cover a wide pectrum of value and that a ubtantial overlap exit between the group. We alo found that pinal flexibility i affected by many individual factor. Thu, the ue offlexibilitymeaurement a a creening tool for the identification of individual who exhibit RO value outide the accepted norm would appear to be no eay tak. To be meaningful, normative information mut take into account uch variable a age, ex, height, itting-to-tanding height ratio, and obeity. A more important iue in the ue offlexibilitymeaure, however, Thi tudy indicate that the pinal RO of a large ample of adult blue collar employee i affected by many individual factor and cover a wide range of value. Determination of what i normal, exceive, or diminihed, therefore, mut take age, ex, and other phyical attribute into account. Thee conideration make the identification of individual who lie outide acceptable RO norm no imple tak. Volume 67 / Number 5, ay 1987 657
REERENCES 1. Locke JC: Stretching away from back pain, injury. Occup Health Saf 52:8-13, 1983 2. Rae PS, Waddell G, Venner R: A imple technique for meauring lumbar pinal flexion. J R Coll Surg Edinb 29:281-284, 1984 3. Guide to the Evaluation of Permanent Impairment, ed 2. Chicago, IL, American edical Aociation, 1984, chap 1 4. Howell DW: uculokeletal profile and incidence of muculokeletal injurie in lightweight women rower. Am J Sport ed 12:278-282, 1984 5. Biering-Sorenen : Phyical meaurement a rik indicator for low-back trouble over a oneyear period. Spine 9:106-119, 1984 6. acrae J, Wright V: eaurement of back movement. Ann Rheum Di 28:584-589, 1969 7. Bird HA, Eatmond CJ, Hudon A, et al: I generalized joint laxity a factor in pondylolithei? Scand J Rheumatol 9:203-205, 1980 8. ayer TG, Tencer A, Kritoferon S, et al: Ue of noninvaive technique for quantification of pinal range-of-motion in normal ubject and chronic low-back dyfunction patient. Spine 9:588-595, 1984 9. Dunham W: Ankyloing pondyliti: eaurement of hip and pine movement. Britih J Phy ed 12:126-129, 1949 10. Loebl WY: eaurement of pinal poture and range of pinal movement. Annal of Phyical edicine 9:103-110, 1967 11. itzgerald GK, Wynveen KJ, Rheault W, et al: Objective aement with etablihment of normal value for lumbar pinal range of motion. Phy Ther 63:1776-1781, 1983 12. Pearcy J, Portek I, Shepherd J: Three-dimenional x-ray analyi of normal movement in the lumbar pine. Spine 9:294-297, 1984 13. Tanz SS: otion of the lumbar pine: A roentgenologic tudy. American Journal of Roentgenology, Radium Therapy and Nuclear edicine 69:399-412, 1953 14. Stoke IA, Wilder DG, rymoyer JW, et al: Aement of patient with low back pain by biplanar radiographic meaurement of intervertebral motion. Spine 6:233-238, 1981 15. Taylor J, Twomey L: Sagittal and horizontal plane movement of the human lumbar vertebral column in cadaver and in the living. Rheumatol Rehabil 19:223-231, 1980 16. Johnon RA, Wichem DW: Applied ultivariate Statitical Analyi. Englewood Cliff, NJ, Prentice-Hall Inc, 1982, chap 8 17. oll JH, Wright V: Normal range of pinal mobility: An objective clinical tudy. Ann Rheum Di 30:381-386, 1971 18. Troup JDG, Hood CA, Chapman AE: eaurement of the agittal mobility of the lumbar pine and hip. Annal of Phyical edicine 9:308-321,1968 19. Howe RG, Idale IC: The looe back: An unrecognized yndrome. Rheumatology and Phyical edicine 11:72-77,1972 658 PHYSICAL THERAPY