Age-related Changes in Maximum Pelvic Anteversion and Retroversion Angles Measured in the Sitting Position (2024)

Abstract

[Purpose] The purpose of this study was to investigate the relationship between age andthe maximum pelvic anteversion and retroversion angles, as well as the associated pelvicrange of motion, measured in a sitting position with free knee movement. [Subjects] Atotal of 132 healthy volunteers (74 women, 58 men; age range, 20–79 years) were dividedinto six groups based on age (20–29, 30–39, 40–49, 50–59, 60–69, and 70–79 years).[Methods] The maximum pelvic anteversion and retroversion angles were measured manuallyfive times by a goniometer in a sitting position that allowed free movement of the kneejoints. [Results] There was a significant effect of age group on the maximum pelvicanteversion and retroversion angles and pelvic range of motion (the difference betweenthese angles). There was a significant correlation between age and the maximum pelvicanteversion angle, maximum pelvic retroversion angle, and pelvic range of motion.[Conclusion] The maximum pelvic anteversion and retroversion angles and pelvic range ofmotion were significantly correlated with age. The maximum pelvic anteversion angle andpelvic range of motion were most affected by age.

Key words: Aging, Mobility limitation, Pelvis

INTRODUCTION

Numerous researchers have investigated the relationship between movements of the lumbarspine and the pelvis^{1, 2)}. The relationship between the pelvic inclination angle and lumbarspine lordosis is more distinct in the sitting position than in the standing position^{1, 3)}.Therefore, lumbar spine (kyphosis and lordosis) mobility may be reflected in seated pelvicmobility (inclination).

Because the pelvis moves forward and backward around the hip joint as a pivotal axis in theseated position, pelvic tilt in the sagittal plane may be affected by flexion and extensionmobility of the hip joints. Since the hamstring muscles originate at the ischial tuberosityof the pelvis, the tension in the hamstring muscles has an effect on pelvic posture^{4, 5)}.Thus, a forward pelvic tilt may increase tension in the hamstring muscles when sitting witha fixed knee angle and the plantar aspect of the foot in contact with the floor. Muyor etal.⁶⁾ reported that the forward pelvictilt angle increased after hamstring muscle stretching, and Feland et al.⁷⁾ confirmed that pelvic mobility in thesagittal plane increased after hamstring muscle stretching in elderly people. The increasein tension in the hamstring muscles when sitting with the soles of the feet in contact withthe floor may restrict pelvic forward tilt. Therefore, free movement of the knees should bepossible during pelvic movement when sagittal plane pelvic mobility is investigated in thesitting position. However, some seated pelvic mobility studies have not clearly describedfoot contact with the floor or the knee joint positioning^{2, 8)}.

In general, joint mobility reduces with advancing age^{9, 10)}. Connective tissuecompliance is considered a major factor in musculoskeletal flexibility⁷⁾. Lumbar spine mobility in both lordosis and kyphosisdecreases with advancing age^{1, 11, 12)}. Keorochana etal.¹³⁾ suggested that the degenerationof the interspinous ligaments with aging is one of the factors contributing to low mobilityof the lumbar spine.

The purpose of this study was to investigate the relationship between age and maximumpelvic anteversion and retroversion angles, as well as the associated pelvic range ofmotion, measured in a sitting position with free knee movement. Pelvic range of motion wasdefined as the difference between the maximum pelvic anteversion and retroversion angles.Due to the close relationship between lumbar spine integrity and mobility and pelvic tilt,we hypothesized that pelvic range of motion would be affected by aging.

SUBJECTS AND METHODS

The participants were 132 healthy volunteers (74 females, 58 males) between the ages of 20to 79 (Table 1). The participants were recruited from a university, two workplaces, and thecommunity near the university after the purpose and contents of the study had beenexplained. Participants were free from neurological and orthopedic impairments. Allparticipants gave informed consent to the experimental protocol, which was approved by theinstitutional ethics committee of Kanazawa University in accordance with the Declaration ofHelsinki (No. 422).

All measurements were taken with the participants seated on a chair with a 50 × 50 cm seatface that was 3 cm thick. The height of the seat surface was 65 cm from the floor to allowfree movement of the knee joints. The participants sat down on the chair, aligning the frontedge of the seat face with the point 66% along the length of the thigh from the greatertrochanter.

In this study, pelvic angles were evaluated by a simple method for measuring the sacralinclination angle¹⁴⁾. A manual goniometerattached to an inclinometer with a resolution of one degree was used to measure pelvicangles. The stationary and moving axes of this goniometer were defined as theanteroposterior axis on the seating face and the longitudinal axis through the midline ofthe dorsal sacral surface, respectively (Fig.1). Therefore, the pelvic tilt angle was defined as the angle between the longitudinalaxis through the midline of the dorsal sacral surface and the anterior horizontal line(Fig. 1).

Subjects were instructed to maintain the same shoulder anteroposterior position throughoutthe movements of pelvic inclination to avoid trunk anteroposterior movement. The instructionto subjects was “Please maintain your shoulder position during pelvic movement”. Aftermaintaining a quiet sitting position for 20 seconds, participants performed alternatingmaximum pelvic anteversion and retroversion positions five times. The maximum and minimumangles were excluded, and the mean of the three remaining values was calculated. The pelvicrange of motion was defined as the difference between the maximum pelvic anteversion andretroversion angles.

One-way ANOVA was used to assess the effect of age group on maximum pelvic anteversionangle, maximum pelvic retroversion angle, and the pelvic range of motion. Post hoc multiplecomparison analysis using Tukey’s honestly significant difference test was used to assesssignificant differences found by ANOVA. Pearson correlations were used to assess therelationships between age and the following parameters: maximum pelvic anteversion angle,maximum pelvic retroversion angle, and pelvic range of motion. All statistical analyses wereperformed using SPSS 19.0 J (SPSS Japan, Tokyo, Japan). The alpha level was set at <0.05.

RESULTS

There was a significant effect of age group on the maximum pelvic anteversion angle(F_{5, 126}=15.8, p<0.001; Table 1). The maximum pelvic anteversion angles in participantsaged 40–49, 50–59, 60–69, and 70–79 years were significantly smaller than in participantsaged 20–29 years (p<0.01, <0.01, <0.001, and <0.001, respectively; Table 1). The maximum pelvic anteversion angles inparticipants aged 60–69 and 70–79 years were significantly smaller than in participants aged30–39 years (p<0.05 for both), and the maximum pelvic anteversion angle was significantlysmaller in participants aged 70–79 than in participants aged 50–59 years (p<0.01; Table 1). There was a significant correlationbetween age and the maximum pelvic anteversion angle (r=0.61, p<0.001;Fig. 2).

There was a significant effect of age group on the maximum pelvic retroversion angle(F_{5, 126}=4.0, p<0.05; Table 1). However, after multiple post hoc comparisons, there were no age groupsthat showed significant differences compared with participants aged 20–29 years. The maximumpelvic retroversion angle was significantly smaller in participants aged 60–69 than inparticipants aged 30–39 years (p<0.05; Table1). There was a significant correlation between age and the maximum pelvicretroversion angle (r=-0.29, p<0.05; Fig. 2).

There was a significant effect of age group on pelvic range of motion(F_{5, 126}=18.7, p<0.001; Table 1). The pelvic ranges of motion were significantly smallerin participants aged 50–59, 60–69, and 70–79 years than in participants aged 20–29(p<0.001 for all) and those aged 30–39 years (p<0.05, <0.001, and <0.001,respectively; Table 1), and the pelvic ranges ofmotion were significantly smaller in participants aged 60–69 and 70–79 years than inparticipants aged 40–49 years (p<0.01 for both; Table 1). There was a significant correlation between age and the range of pelvicmotion (r=−0.63, p<0.001; Fig.2).

DISCUSSION

In the present study, pelvic angles were evaluated by a simplified measuring method for thesacral inclination angle¹⁴⁾. The maximumpelvic anteversion angle, maximum pelvic retroversion angle, and range of pelvic motion weresignificantly affected by aging. The relationships between these variables and age wereapproximated using linear regression equations. These results indicate that pelvic mobilityin the sitting position is affected by aging.

Hamstring tension probably had an insignificant effect on pelvic mobility in this study,especially on anterior tilt, because the knees had free mobility during pelvic movement. Thehip flexion angle during maximum pelvic anteversion was 95° in participants aged 20–29 yearsand 87° in participants aged 70–79 years. The hip flexion angle during maximum pelvicretroversion was 57° in participants aged 20–29 years and 63° in participants aged 70–79years. The passive hip joint flexion and extension angles in the elderly were approximately120° and 17°, respectively⁹⁾. Therefore,pelvic mobility in the present study did not seem to be affected by hamstring muscle tensionor hip joint mobility. The pelvic mobility measured in this study fairly reflected thelumbar spine mobility based on previously reported strong correlations between pelvic tiltor sacral tilt angle and the lumbar spine lordosis angle in the sitting position^{1, 14, 15)}. In addition, pelvic mobility is larger inthe sitting position than in the standing position²⁾. Therefore, changes in the maximum pelvic anteversion andretroversion angles with aging might be directly affected by the changes in lumbar spinemobility that occur with aging¹²⁾.However, due to aging-related shortening of the hamstring muscles, the maximum pelvicanteversion angle may be more restricted when performing this movement without free mobilityat the knee.

The pelvic range of movement was about 40° in participants aged 20–29 years, while it was24° in participants aged 60–69 and 70–79 years. The rate of pelvic mobility limitation withaging in this study (about 30%) is larger than that previously reported for hip extension(20%), which is considered the most limited joint in the lower extremities⁹⁾. Therefore, sagittal plane pelvic mobilitymay be an important factor related to mobility limitation for sit-to-stand movement inelderly adults.

A manual goniometer attached to an inclinometer with a resolution of one degree was used inthe present study. Therefore, the reliability of manual goniometer measurement was probablyguaranteed by the inclinometer¹⁶⁾.However, the test-retest reliability should be evaluated.

References