Between-side symmetry of quadriceps thickness using ultrasound imaging in female golfers and non-golfers aged over 80 years

Abstract

Purpose: The main goal of the research was to identify if an active, sedentary, or institutionalised lifestyle in females over 80 years produces a different profile in quadriceps symmetry to see if this is a potential biomarker for health status and physical independence. The aim of the research was two-fold: 1- to examine the influence of level and type of lifestyle activity on quadriceps asymmetry in females over 80 years. 2- to use ultrasound imaging, a well-established, rapid, simple, valid and reliable technique to obtain preliminary reference data for thickness of quadriceps muscles on dominant and not dominant lower limbs in females over 80 years across the activity spectrum. Methods: This was a cross-sectional observational study in a convenient sample of 42 females over 80 years old, comprising 20 active golfers from clubs in Hampshire (aged 82.75±2.12, range 80–87 years ), 10 sedentary women living independently in the local community (80.80±1.03, 80–83 ) and 12 women in residential care (88.16±6.57, 80–98). Transverse images of the anterior thigh were produced using a real-time B-mode ultrasound scanner (Imagic Agile, Pie Data, Ltd), with a 5–6.6 MHz curvilinear transducer, on the dominant and not dominant limbs. Two images of the quadriceps muscle were taken for each participant in the same session, and the mean value of the two corresponding ultrasound measurements was used in the analysis. To analyse the images offline, a Matlab algorithm was used to export the data to a Microsoft Excel file. Kolmogorov-Smirnov test was utilized to assess the normality of distribution for tested variables. Comparison of quadriceps thickness between the dominant and not dominant side within each group was performed using a paired t-test when the distribution of data was found to be normal for both sides (golfers group), and using the paired Wilcoxon test for non-normally distributed data (sedentary and residential care groups). The level of asymmetry was expressed as the percentage difference of quadriceps thickness between the two sides (larger minus smaller side x 100) in each group, and the actual differences were compared between the three groups using a one-way ANOVA. The linear relationship between quadriceps thickness between the dominant and not dominant by groups (golfers, sedentary group and women in residential care) was studied using a general linear model. Results: The quadriceps thickness values were similar in the sedentary (both sides mean 1.95cm SD dominant±0.38, non-dominant±0.86) and residential care (dominant 1.93±0.84, non-dominant 1.77±0.86) groups, whereas thickness values were statistically greater on the non-dominant side in the golfers (1.92±0.34 cm, 2.10±0.50 cm on dominant and non-dominant sides respectively). The linear relationship between thickness of dominant and non-dominant limbs was significantly different between groups (p<0.001), showing asymmetry in golfers and residential care groups, but with the reverse trends: golfers had significantly greater thickness of the non-dominant quadriceps (−18% difference; p=0.014), while the residential care group had thicker muscles on the dominant side (16% difference) but this was not significant, possibly due to high standard deviations and small number of participants. The sedentary group showed high symmetry (3% difference). Fig.1. Box plots; dominant (striped) versus non dominant (solid) quadriceps thickness (cm). Conclusions: The high level of symmetry of quadriceps thickness in the sedentary group was as expected from the literature (i.e. less than 10%). The asymmetry in the residential care group, with the dominant side being larger, is a known risk of falling. The larger muscles on the non-dominant side in golfers suggest a training effect of the golf swing technique, where the leading leg (non-dominant side in right side dominant players) bears the body weight during swing through, therefore undergoing grater loading. Although using ultrasound imaging is a very accurate and useful assessment technique in community settings, the present results highlight the importance of considering activity history when interpreting results in older people, as asymmetry increases at both ends of the activity spectrum. Other training effects of golf on the musculoskeletal system in recreational players warrant investigation using mixed methods research, to examine beneficial effects on joint health and symptoms, and to gain insights for adherence strategies to enable people living with osteoarthritis to have an active lifestyle.