Anthropometric Measurements



Sample Anthropometric Measurement Form
2002 Study Summary
What the Results Tell Us
Tables of 2002 Data
Diagrams of Shoulder Range of Motion Differences




Sample Anthropometric Measurement Form

Subject # __________

In order to establish baseline levels for the subject population the following measurements will be taken. Each measure will be taken in the order that follows to insure consistency between subjects. A definition and clarification of each measurement will also be provided.
  1. Dominant Hand: RIGHT/LEFT
  2. Birth Date:
  3. Height: Standing height taken in inches
  4. Weight: Measured in pounds on a standard scale
  5. Body Fat: Three site body fat composition (triceps, umbilicus, pectoralis)
  6. Upper arm girth: Widest measurement of biceps brachii muscle in inches
    Right:
    Left:
  7. Chest girth: Measurement taken at nipple line in inches
  8. Forearm girth: Widest part of the forearm measured in inches
    Right:
    Left:
  9. Shoulder Range of Motion
    • Measurement, in degrees, of shoulder internal rotation while the shoulder is in 0 degrees of abduction
      Right:
      Left:
    • Measurement (in degrees) of shoulder external rotation while the shoulder is in 0 degrees of abduction
      Right:
      Left:
    • Measurement (in degrees) of shoulder internal rotation while the shoulder is horizontally abducted to 90 degrees
      Right:
      Left:
    • Measurement (in degrees) of shoulder external rotation while the shoulder is horizontally abducted to 90 degrees
      Right:
      Left:
    • Measurement (in degrees) of shoulder flexion in the sagittal plane
      Right:
      Left:
    • Measurement (in degrees) of shoulder abduction
      Right:
      Left:
  10. Elbow flexion/extension range of motion
    Right:
    Left:
  11. Internal Rotation of the shoulder: Determined by the most superior spinous process reached by the patient when reaching
    with the thumb
    Right:
    Left:
  12. Measurement (in degrees) of the elbow
    Valgus:
    • Right:
    • Left:

    Varus:
    • Right:
    • Left:
  13. Sulcus Sign as defined by Magee (1998): Y/N
  14. Load and Shift Test as defined by Magee (1998):
    Right:
    Left:
  15. Grip Strength: Measured by a hand dynamometer
    Right:
    Left:
  16. Biodex evaluation of shoulder internal and external rotators taken with the arm in 0 degrees of abduction at testing speeds of 180 and 420 degrees per second. Each subject will perform five and then 10 repetitions on the Biodex at the 180 and 420 degrees per second speeds, respectively. Strength will be measured in Newtons and will be a representative of torque production. A standard Biodex protocol will be followed for set-up.
    
    
    



    2002 Study Summary

    Introduction

          Youth sports in the United States grow increasingly more competitive each year (Gill & Micheli, 1996; Outerbridge & Micheli, 1995). Children are involved in organized sports earlier and at a higher intensity level than ever before. Children involved in all competitive athletic pursuits are susceptible to injury due to normal growth, disease state and training error (Gill & Micheli, 1996). For youth baseball pitchers, the risks of injury are two-fold. These risks include overuse injuries imposed by the sport, as well as the increased risk of injury associated with the developing body (Gill & Micheli, 1996; Ireland & Andrews, 1988; Outerbridge & Micheli, 1996; Wilson, Andrews & Blackburn, 1983). With the amount of growth that occurs in children, their bodies are highly susceptible to structural changes secondary to internal and external forces.

          Baseball pitchers of all ages are prone to injury due to the extreme magnitude and repetitive nature of the forces involved in the overhand pitching motion. The combination of forces during the pitching motion, coupled with the physiological limitations of the shoulder, elbow and wrist joints, predisposes the athlete to upper extremity injuries, such as anterior shoulder instability (Bigliani et al., 1997; Lippitt & Matson, 1993; Meister, 2000; Neer & Welsh, 1977; Rodosky, Harner & Freddie, 1994; Warner et al., 1990). Historically, explanations for these injuries focused on an inadequacy of the muscular and ligamentous components of the shoulder (Moseley & Overgard, 1962; Saha, 1967). Recently, there has been a shift toward viewing the osseus components of the shoulder as an essential factor in allowing these muscular and ligamentous constraints to fulfill their stabilizing roles (Dias, Mody, Finlay & Richardson, 1993).

          Understanding the acute and chronic effects of overhand pitching will assist in maintianing the overall health of the youth pitcher's shoulder/arm complex. In light of the influence that physical activity has on the developing bones and the effect that baseball pitching has on the structure of the shoulder/arm complex, the presence of anomalies within the elite pitcher's shoulder/arm complex must be evaluated. Initial results in the this longitudinal investigation have indicated that structural anomalies are seen in the arms of elite youth baseball pitchers as young as twleve years of age.

    Purpose and Hypotheses

         It was the purpose of this research project to establish an anthropometric profile of an elite 11-year-old male baseball pitcher. Anthropometric measurements were compared to an active, age-matched, non-throwing control group (NCG). The following research questions were addressed:
    1. Are the anthropometric measurements of 11-year-old elite baseball pitchers, with the exception of upper extremity passive range of motion (PROM) and joint mobility significantly different from an active, age-matched, non-throwing control group?
      • It was hypothesized that these measurements would not differ significantly between groups, indicating that these two groups are gleaned from a single homologous population of active 11-year-old males.
    2. Do upper extremity measurements of PROM and joint mobility differ between dominant and non-dominant arms in 11-year-old elite youth baseball pitchers?
      • It was hypothesized that external rotation (ER) at 90° of shoulder abduction would be significantly greater in the dominant arm as compared to the non-dominant arm.
      • It was hypothesized that internal rotation at 90° of shoulder abduction would be significantly less in the dominant arm as compared to the non-dominant arm.
      • It was hypothesized that anterior and inferior shoulder joint mobility would be significantly increased in the dominant arm as compared to the non-dominant arm.
    3. Do upper extremity measurements of PROM and joint mobility differ between dominant and non-dominant arms in the active, age-matched, non-throwing population?
      • It was hypothesized that there would be no significant difference between these measurements.
    4. Are the upper extremity measurements of PROM and joint mobility of 11-year-old baseball pitchers signicantly different than that of an active, age-matched, non-throwing control group?
      • It was hypothesized that the measurements of the non-dominant arms would not differ significantly between populations.
      • It was hypothesized that the dominant shoulder of the baseball group would demonstrate significantly increased ER and decreased IR at 90° of shoulder abduction compared to the dominant shoulder of the active, age-matched, non-throwing control group.
      • It was hypothesized that the anterior and inferior joint mobility of the baseball pitcher's shoulder would be significantly greater than the dominant shoulder of the active, age-matched, non-throwing control group.

    Methods

         This study compared the anthropometric measurements of 11-year-old elite male baseball pitchers currently participating in a competitive little league baseball program to an active, age-matched, non-throwing control group. Measurements taken include:

    • height
    • weight
    • arm girth
    • chest girth
    • shoulder passive range of motion
    • elbow passive range of motion
    • glenohumeral joint mobility
    • elbow joint mobility

    Results


    • Anthropometric measurements, except for shoulder IR and ER were not significantly different between the pitching group and the active, age-matched, non-throwing control group

    • 2 Statistically significant differences:
      • The ratio of non-dominant shoulder IR at 90° of shoulder abduction in baseball pitchers as compared to the control group.
      • The ratio of dominant to non-dominant shoulder ER at 90° of shoulder abduction in baseball pitchers as compared to the control group.

    • 2 non-statistically significant trends:
      • Increased ER and decreased IR at 90° of shoulder abduction in the dominant arm of baseball pitchers.
      • Increased ER and decreased IR at 0° of shoulder abduction for baseball pitcher's dominant arm compared to the non-dominant arm.
    
    
    



    What the Results Tell Us

    Discussion

         The results suggested that the dominant arm of baseball pitchers had increased shoulder ER and decreased IR at 90° of glenohumeral abduction compared to their non-dominant side. The control group did not appear to have notable differences between sides. This shift toward external rotation in baseball pitcher's dominant arms could be due, in part, to the repetitive overhead throwing motion that requires the pitching arm to be in maximal external rotation during the late-cocking phase of pitching (Dillman, Fleisig & Andrews, 1993). With repetitive use of the overhead throwing motion, dynamic and static constraints surrounding the glenohumeral joint may become lax into the motion of shoulder ER at 90° of glenohumeral abduction. It is reasonable to assume that through repetitive throwing movements into the end range of these two motions, the inferior glenohumeral ligament, middle glenohumeral ligament and anterior capsule have increased stress placed on them, allowing a greater degree of mobility into ER at 90° of glenohumeral abduction to occur.
         As the anterior static stabilizers of the glenohumeral joint are stretched with the overhead pitching motion, the posterior stabilizers remain relaxed. The posterior band of the inferior glenohumeral ligament, along with the posterior capsule, are the two primary structures that resist the motion of shoulder IR at 90° of glenohumeral abduction (O'Brien et al., 1990). If these structures remain in a relaxed position over time, they may adaptively shorten, thus decreasing the amount of IR of the shoulder at 90° of glenohumeral abduction.
         Another possible explanation as to the differences seen in the PROM between the pitcher's dominant and non-dominant shoulders could be a change in the humeral torsion angle of the dominant arm due to the repetitive stresses placed upon the humerus during the throwing motion. Wolff's Law suggests that new bone growth occurs in response to the stresses placed upon that bone (Levangie & Norkin, 2001). The continuous throwing motion with the pitcher's dominant arm could place enough stress on the humerus to change the osseus configuration of that bone into a position of increased humeral retrotorsion. This increase would allow the pitcher to move into a greater range of ER at 90° of glenohumeral abduction before the head of the humerus translates anteriorly on the glenoid. It would also decrease the amount of IR at 90° of glenohumeral abduction that can be performed prior to prior to posterior translation of the head of the humerus on the glenoid. Ultimately, this would manifest itself as an increase in ER and a decrease in IR at 90° of glenohumeral abduction.
         Support for this second hypothesis regarding adaptive humeral retrotorsion was found when comparing the ER and IR measurements at 0° of glenohumeral abduction. Although not statistically significant, a trend was noted indicating a greater amount of ER and a smaller range of IR on the pitcher's dominant shoulder compared to the non-dominant shoulder, while the active, age-matched, non-throwing control group demonstrated similar measurements bilaterally. At 0° of glenohumeral abduction, different static constraints are used to limit the motions of ER and IR. In addition, the overhand throwing motion does not occur at 0° of glenohumeral abduction, possibily indicating that the osseus configuration of the pitcher's dominant humerus is changed rather than the static constraints surrounding the glenohumeral joint.

    Conclusions

         These results suggest that, overall, the dominant arms of baseball pitchers have increased shoulder ER and decreased shoulder IR at 90° of glenohumeral abduction compared to their non-dominant side. The results of the non-throwing control group did not demonstrate these differences. Future research is needed to address the differences that appear to be present between the dominant and non-dominant arms of the elite baseball pitchers. Utilization of computed tomography scanning may serve to elucidate the role of osseus torsional changes in youth baseball pitchers. The probable causes and implications of these differences must also be investigated.

    
    
    



    Tables of 2002 Data


    Table One: Mean Baseball ER and IR Range of Motion at 90° Humeral Abduction and Ratio of Dominant to Non-Dominant Arms
    IRER
    Dominant Arm43.86121.57
    Non-dominant Arm58.79108.86
    Ratio Dominant:Non-Dominant0.751.12


    Table Two: Mean Soccer ER and IR Range of Motion at 90° Humeral Abduction and Ratio of Dominant to Non-Dominant Arms
    IRER
    Dominant Arm50.18122.90
    Non-dominant Arm53.09117.90
    Ratio Dominant:Non-Dominant0.951.04


    Table Three: Mean Baseball ER and IR Range of Motion at 0° Humeral Abduction and Ratio of Dominant to Non-Dominant Arms
    IRER
    Dominant Arm13.5076.21
    Non-dominant Arm11.7467.50
    Ratio Dominant:Non-Dominant1.151.13


    
    
    

    Table Four: Mean Soccer ER and IR Range of Motion at 0° Humeral Abduction and Ratio of Dominant to Non-Dominant Arms
    IRER
    Dominant Arm11.1879.73
    Non-dominant Arm10.7382.00
    Ratio Dominant:Non-Dominant1.040.97


    Table Five: Evidence of Homogenous Grouping of 11-year-old Baseball and Control Groups
    Group MeanSignificance
    Weight (Baseball)89.210.67
    Weight (Control Group)92.23
    Height (Baseball)57.690.43
    Height (Control Group)59.25
    Chest Girth (Baseball)72.400.54
    Chest Girth (Soccer)73.93
    Right Forearm Girth (Baseball)21.790.55
    Right Forearm Girth (Soccer)22.20
    Left Forearm Girth (Baseball)21.570.61
    Left Forearm Girth (Soccer)21.25
    Right Upper Arm Girth (Baseball)22.090.78
    Right Upper Arm Girth (Soccer)22.33
    Left Upper Arm Girth (Baseball)22.250.67
    Left Upper Arm Girth (Soccer)21.89



    Diagrams of Shoulder Range of Motion Differences























Special Thanks to Courtney Faust of Tridig.com for creating the Diagrams

E-mail Courtney Faust