Rotational strength, range of motion, and function in people with unaffected shoulders from various stages of life.

Abstract

Different measurements are used to assess shoulder function, including range of motion, strength, functional performance and self-report function. To understand disablement, it is necessary to understand the relationship between impairments and function in persons without shoulder problems. This study was conducted to enhance existing comparative data in subjects without upper extremity pathology, and to assess the relationships between impairments (range of motion, strength) and self-reported or measured function/disability. The impact of age, gender and dominance was determined.
Two-hundred ninety-four subjects with unaffected shoulders were recruited. The subjects (mean age: 37 years old) were divided into three subgroups, 18-39, 40-59, and over 60 years of age. During a single session, at least two of the following variables were measured: self-reported function (shoulder disability scales), range of motion, isometric rotational strength, or upper limb functional performance (FIT-HaNSA). Two-way analysis of variance was used to determine, for each variable, the effects of age and gender. The relationship between the outcomes was established using Pearson product correlations.
Men were significantly stronger than women for all age categories. There was an age-related decline in strength in men in the over-60 age category. Significant negative correlations between strength and range of motion were demonstrated (-0.22 <r < -0.32). Women had a significantly higher range of motion than men for external rotation in the 40-59 age category. Furthermore, the subjects in the over-60 age category experienced a decrease of range of motion. There was minimal disability reported in all age groups on self-report scales. Only the Simple Shoulder Test demonstrated significant decreases in the over-60 age category and correlated with age (r = -0.202).
Self-reported disability was low in individuals without upper extremity problems, although recruitment of such individuals was difficult in the older age groups due to the high prevalence of shoulder pathology. A low correlation between self-report disability and strength/range of motion in these unaffected subjects reflects the lack of disability reported by all subjects without pathology despite normal variations in strength and motion.

Full text

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BioMed Central
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Sports Medicine, Arthroscopy,
Rehabilitation, Therapy & Technology
Open Access
Research
Rotational strength, range of motion, and function in people with
unaffected shoulders from various stages of life
Jean-Sébastien Roy*1, Joy C MacDermid1,2, Kirsty Usher Boyd2,
Kenneth J Faber2, Darren Drosdowech2 and George S Athwal2
Address: 1School of Rehabilitation Science, McMaster University, Hamilton, Ontario, L8S 1C7, Canada and 2Hand and Upper Limb Centre, St.
Joseph's Health Centre, London, Ontario, N6A 4L6, Canada
Email: Jean-Sébastien Roy* - jean-sebastien.roy.1@ulaval.ca; Joy C MacDermid - macderj@mcmaster.ca;
Kirsty Usher Boyd - kuboyd@gmail.com; Kenneth J Faber - kjfaber@uwo.ca; Darren Drosdowech - ddros@mac.com;
George S Athwal - gathwal@uwo.ca
* Corresponding author
Abstract
Background: Different measurements are used to assess shoulder function, including range of motion,
strength, functional performance and self-report function. To understand disablement, it is necessary to
understand the relationship between impairments and function in persons without shoulder problems.
This study was conducted to enhance existing comparative data in subjects without upper extremity
pathology, and to assess the relationships between impairments (range of motion, strength) and self-
reported or measured function/disability. The impact of age, gender and dominance was determined.
Methods: Two-hundred ninety-four subjects with unaffected shoulders were recruited. The subjects
(mean age: 37 years old) were divided into three subgroups, 18–39, 40–59, and over 60 years of age.
During a single session, at least two of the following variables were measured: self-reported function
(shoulder disability scales), range of motion, isometric rotational strength, or upper limb functional
performance (FIT-HaNSA). Two-way analysis of variance was used to determine, for each variable, the
effects of age and gender. The relationship between the outcomes was established using Pearson product
correlations.
Results: Men were significantly stronger than women for all age categories. There was an age-related
decline in strength in men in the over-60 age category. Significant negative correlations between strength
and range of motion were demonstrated (-0.22 <r < -0.32). Women had a significantly higher range of
motion than men for external rotation in the 40–59 age category. Furthermore, the subjects in the over-
60 age category experienced a decrease of range of motion. There was minimal disability reported in all
age groups on self-report scales. Only the Simple Shoulder Test demonstrated significant decreases in the
over-60 age category and correlated with age (r = -0.202).
Conclusion: Self-reported disability was low in individuals without upper extremity problems, although
recruitment of such individuals was difficult in the older age groups due to the high prevalence of shoulder
pathology. A low correlation between self-report disability and strength/range of motion in these
unaffected subjects reflects the lack of disability reported by all subjects without pathology despite normal
variations in strength and motion.
Published: 2 March 2009
Sports Medicine, Arthroscopy, Rehabilitation, Therapy & Technology 2009, 1:4doi:10.1186/1758-2555-1-4
Received: 3 November 2008
Accepted: 2 March 2009
This article is available from: http://www.smarttjournal.com/content/1/1/4
© 2009 Roy et al; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0),
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Background
There is an increased emphasis on using subjective and
objective outcome measures to characterize function in
persons with shoulder disorders [1-4]. In particular, out-
come assessments increasingly encompass terminology
and concept from the International Classification of Func-
tioning, Disability and Health [5]. For shoulder disorders,
impairments most commonly measured include range of
motion and strength. Disability includes activity limita-
tions and participation restrictions that are often best
measured by self-report questionnaires. Activity limita-
tions can also be assessed by performance-based tests. It is
important to understand the relationship between
impairments and measure of function/disability in per-
sons without shoulder problems, as well as the effects of
age and gender on these different aspects of shoulder
function.
The importance of objective measurements of strength
and range of motion when evaluating shoulders is evi-
denced by the frequency with which they are reported in
the literature [2,4,6-9]. Objective assessment of strength
provides information on integrity of the rotator cuff [10]
and is used to gauge the recovery of muscle function fol-
lowing intervention [11,12]. Normative data is required
for comparison to grade the extent of recovery. Otis et al.
discussed the value of assessing strength relative to a
matched population, especially in the presence of a shoul-
der deficit, in order to characterize these deficits [13].
Moreover, Hughes et al. noted the importance of having
unaffected shoulders data for comparison in patients
whose shoulder deficits manifest with bilateral involve-
ment [14]. Kuhlman et al. acknowledged that while many
studies have attempted to define normal values for the
strength of shoulder muscles, there have been varying
degrees of success because of a lack of standardization
(plane of motion, position of the shoulder or stabilization
of the body) [15].
Gender related differences in strength have been reported
[14,16]. More specifically, Hughes et al. have shown that
men are stronger than women when controlling for age
and weight [14]. The effects of age and dominance, how-
ever, are less well known. It has been suggested that, in the
normal population, age is negatively associated with iso-
metric shoulder strength and that some shoulder rota-
tional strength measurements differ between dominant
and nondominant sides [14,16]. Studies examining range
of motion and its relationships with age, gender and dom-
inance, unfortunately, have reported varied results [17-
19]. Most studies have reported that only some shoulder
motions decrease with age [17,18], however, the specific
shoulder ranges of motion affected by age are inconsistent
between studies. As for gender-related effects, minimal
differences between genders have been described by Mur-
ray et al. [18], while Barnes et al. observed greater range of
motion in women as compared to men [17].
Measures of function provide a broader view of patient
status and are considered more patient centered. Several
studies have examined the contribution of self-report
questionnaire to disability assessment, or reported on
their validity [20,21]. Unfortunately, very few studies have
established normative values for these self-report scales
[21]. Furthermore, those that have presented normative
values have not included a determination of how self-
reported function is related to strength and range of
motion [7,13-16,21,22].
Recently, an upper-extremity functional performance test,
the FIT-HaNSA, has been proposed by MacDermid et al
[23]. This standardized test was developed to assess func-
tional performance for sustained upper extremity activity.
The reliability and concurrent validity of the FIT-HaNSA
have been established in persons with shoulder disorders.
It has been shown to discriminate between persons with
and without shoulder disorders. Normative data for the
FIT-HaNSA has yet to be published. Furthermore, the rela-
tion between the FIT-HaNSA and strength, range of
motion and self-reported function has not been estab-
lished for individuals without shoulder pathology.
The purpose of this investigation is to enhance existing
comparative data on normal shoulder range of motion
and strength, and to add information on functional per-
formance and self-reported function. A secondary pur-
pose is to establish the inter-relationships between these
different types of assessments and to evaluate the impact
of dominance, age and gender. The hypotheses are that
men will be stronger than women in all age categories.
Furthermore, rotational strength, range of motion, func-
tional performance and upper extremity function will be
decreased in the over-60 age category compared to the 18–
39 and 40–59 age categories.
Methods
Subjects
Two-hundred ninety-four subjects voluntarily partici-
pated in the study (121 men and 173 women). The sub-
jects were divided into three age cohorts, 18–39, 40–59,
and over-60. The mean subject age was 36.9 years and the
range was from 18 to 79 years (Table 1). Subjects were first
specifically recruited for this study by a variety of meth-
ods, including flyers advertising the study, people accom-
panying their spouses to the Hospital, and word of mouth
(n = 128; variables evaluated: strength, range of motion
and self-reported function). Separate groups of subjects
participated in studies evaluating the psychometric quali-
ties of the FIT-HaNSA (n = 125; variables evaluated: upper
limb functional performance and self-reported function

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and/or range of motion and/or strength) and the concom-
itant validity of isometric strength devices (n = 41; varia-
bles evaluated: strength and self-reported function).
Inclusion criteria were: 1) age 18 and above; 2) a self-
reported normal upper limb function (no pain or move-
ment limitation); 3) no history of surgery to the upper
limb; and 4) no previous diagnosis or treatment to any
part of the upper extremity. Subjects had to report that
they had no problems with their shoulder at the time of
the assessment. Most had no history of injury. Six sub-
jects, however, had sustained fractures more than ten
years previously (2 finger fractures, 2 radial head fractures,
and two clavicle fractures). Two subjects also admitted to
a remote history of lateral epicondylosis. All of these indi-
viduals characterized their injuries as distant, their recov-
ery as complete and their upper limb function as normal
and unaffected. Therefore, they were included. This study
was approved by our Institutional Review Board.
The test session involved the measurement of at least two
of the following variables: self-reported shoulder and
upper extremity function, range of motion, strength or
upper limb functional performance (FIT-HaNSA). Sepa-
rate subgroups of volunteers were enrolled sequentially
for the strength/motion and functional performance sub-
sets for the study. The subjects were assessed by research
assistants following standardized tests procedures.
Test Procedures
Strength
Shoulder internal and external rotation isometric strength
was measured in Newton metres (Nm) using a computer-
ized dynamometer (LIDO WorkSET™; Loredan Biomedi-
cal, West Sacramento, California). These muscles groups
were chosen since they are the ones usually involve in
patients with shoulder disorders such as rotator cuff tend-
inosis or tear [8]. Testing was performed with subjects
seated in a heavy straight-backed chair with both feet flat
on the floor. The arm to be tested was positioned with 30°
forward flexion and abducted to 45° (in the plane of the
scapula) as per Leroux et al. [7]. The machine axis was
adjusted to 45° so that it was aligned with the longitudi-
nal axis of the humerus. The subject grasped a handgrip in
neutral position for forearm pronation/supination. Iso-
metric internal and external rotations were tested bilater-
ally with machine calibration between each test. Three
measurements were averaged for each muscle group. The
LIDO WorkSET™ has been shown to have excellent relia-
bility in the measurement of isometric internal and exter-
nal shoulder rotation strength with intraclass correlation
coefficient (ICC) of 0.88 to 0.94 [8].
Range of Motion
Active and passive internal and external rotation range of
motion was assessed bilaterally using a goniometer (in
degrees). External rotation was measured in both the sit-
ting and supine positions, whereas internal rotation was
only measured supine. For sitting external rotation, sub-
jects were seated in a straight-backed chair with both feet
flat on the floor. Measurements were taken during active
motion with the humerus at 0° of abduction and elbow at
90° of flexion. The olecranon process was used as the axis
of rotation [20]. Supine external and internal rotations
were measured passively with the humerus abducted in
the frontal plane to 90° and the elbow flexed to 90°. The
scapula was stabilized during internal rotation by the
research assistant in order to avoid protraction of the
shoulder girdle. The scapula was not stabilized in external
Table 1: Subjects characteristics and self-report function in men and women by age.
nAge (years) DominanceDASHSSTWORC
Mean*Right/leftMean*Mean*Mean*
Men
18–39
40–59
60+
121
71
30
20
39.2 ± 16.6
27.1 ± 5.5
48.5 ± 5.3
68.2 ± 5.7
106/15
62/9
26/4
18/2
1.8 ± 3.1 (n = 100)
1.8 ± 2.9 (n = 54)
1.1 ± 2.9 (n = 27)
2.6 ± 3.8 (n = 19)
11.6 ± 1.6 (n = 60)
11.9 ± 0.4 (n = 25)
11.8 ± 0.5 (n = 19)
10.9 ± 3.0 (n = 16)
6.4 ± 12.0 (n = 59)
5.8 ± 13.6 (n = 25)
6.9 ± 12.7(n = 18)
6.9 ± 8.5 (n = 16)
Women
18–39
40–59
60+
173
112
44
17
35.3 ± 15.1
25.4 ± 6.2
48.8 ± 5.1
64.9 ± 4.8
157/16
99/13
42/2
16/1
1.8 ± 2.8 (n = 155)
1.7 ± 2.4 (n = 96)
2.0 ± 3.6 (n = 43)
1.9 ± 2.6 (n = 16)
11.7 ± 1.5 (n = 70)
12.0 ± 0.2 (n = 27)
11.8 ± 0.5 (n = 31)
10.9 ± 3.4 (n = 12)
5.4 ± 8.3 (n = 70)
3.9 ± 3.9 (n = 27)
7.7 ± 11.4 (n = 31)
3.1 ± 3.9 (n = 12)
Total
18–39
40–59
60+
294
183
74
37
36.9 ± 15.9
26.1 ± 6.0
48.7 ± 5.1
66.6 ± 5.5
263/31
161/22
68/6
34/3
1.8 ± 2.9 (n = 255)
1.8 ± 2.6 (n = 150)
1.7 ± 3.4 (n = 70)
2.3 ± 3.2 (n = 35)
11.7 ± 1.5 (n = 130)
11.9 ± 0.3a (n = 52)
11.8 ± 0.5b (n = 50)
10.9 ± 3.1a, b (n = 28)
5.9 ± 10.1 (n = 129)
4.8 ± 9.8 (n = 52)
7.4 ± 11.8 (n = 49)
5.3 ± 7.1 (n = 28)
Significant differences for the SST between: a18–39 and over-60 age categories; b40–59 and over-60 age categories. * Mean ± 1 SD.
Abbreviation: n, Number of subjects.

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rotation. Passive external/internal rotation of the shoul-
der was performed to subject tolerance with the olecranon
serving as the axis of rotation as per the American Acad-
emy of Orthopaedic Surgeons [24]. The movement was
stopped when the first resistance was felt. Intratester relia-
bility of shoulder movements using a goniometer has
been shown to be excellent with ICC of 0.88 to 0.93 [25].
Functional performance
The FIT-HaNSA was used to evaluate the upper-limb func-
tional performance. The FIT-HaNSA is a test battery of 3
tasks that simulate activities of lifting and sustained over-
head work [23]. In the first task, a shelf was placed at waist
level and a second shelf was placed 25 cm above it. Three
1-kg containers were placed 10 cm apart on the lower
shelf. Using the dominant arm, the patient had to lift the
three containers, one at a time, from one shelf to the other
at a speed of 60 beats per minute, controlled by a metro-
nome. The subjects were instructed to do the test until five
minutes have elapsed or they feel unable to continue. The
time was measured in seconds by a stopwatch. In the sec-
ond task, the shelves were adjusted so that one shelf was
placed at the subject's eye level and the second shelf was
placed 25 cm below it. The subjects had to lift the three
containers between the shelves at a speed of 60 beats per
minute. In the third task, a shelf was placed at the subject's
eye level with an attachable plate, perpendicular to the
shelf. Subjects had to use their dominant arm to repeat-
edly screw and unscrew bolts in a pattern into the plate. A
30 seconds rest period was given between each test. The
same stopping protocol was used for the three tasks. The
stopping criteria included subject fatigue and examiner's
assessment of fatigue (substitute movement) [23]. A total
score was calculated by averaging the time for the three
tasks. The FIT-HaNSA has been shown to significantly dis-
criminate between subjects with and without shoulder
pathologies [23].
Self-report upper extremity function
Three self-reported disability scales were employed to
assess shoulder and upper limb function. These included
a joint-specific (Simple Shoulder Test [SST]), an upper-
extremity disability (Disabilities of the Arm, Shoulder,
and Hand [DASH]) and a condition-specific (Western
Ontario Rotator Cuff [WORC]) questionnaire. All subjects
completed at least one of these instruments. Each instru-
ment varied with respect to the number of items included
(SST with 12, DASH with 30, and WORC with 21) and
with respect to time to completion (DASH and WORC in
3 minutes, SST in 1.5 minutes) [1]. The DASH measures
physical disability and symptoms of the upper limb [26].
It addresses difficulty in performing various physical activ-
ities that require upper extremity function (21 items);
symptoms of pain, activity-related pain, tingling, weak-
ness and stiffness (5 items); or impact of disability and
symptoms on social activities, work, sleep and psycholog-
ical well-being (4 items). The DASH scores range from 0
(no disability) to 100 (most severe disability). The SST
measures functional limitations of the affected shoulder
[27]. The SST consists of dichotomous (yes [1] or no [0])
response options. For each question, the patients indicate
that they are able or are not able to do the activity. The
scores range from 0 (worst) to 12 (best). The WORC is a
questionnaire developed to measure health related qual-
ity of life in patients with rotator cuff disease [28]. WORC
consists of 21 items in 5 domains: physical symptoms (6
items), sports and recreation (4 items), work (4 items),
lifestyle (4 items) and emotions (3 items). The WORC
scores range from 0 (best possible) to 100 (worst possi-
ble). These three scales have been shown to be valid, reli-
able (test-retest reliability > 0.90) [28-30] and responsive
(effect size/standardized response mean > 0.80)
[29,31,32].
Analyses
Descriptive statistics for strength, range of motion, func-
tional performance and self-report for each age/gender
cohort were calculated. Two-way analysis of variance
(ANOVA) was used to determine, for each variable, the
effects of age and gender. The factors in the model were
gender (men or women) and age categories (18–39, 40–
59, and over-60). ANOVA and independent t-tests, with
Bonferroni adjustment, were used for multiple pairwise
comparisons. Paired t-tests were used to evaluate the effect
of dominance on range of motion and strength. To estab-
lish the inter-relationships between the different types of
variables, correlations between age, strength, range of
motion, functional performance and self-reported func-
tion were examined using Pearson product. The majority
of the skewness and normality tests indicated normality
was present. Some of the self-report data was skewed to
low scores, but not sufficiently to warrant non-paramet-
rics. An alpha level of 0.05 was used for all tests. All anal-
yses were conducted with SPSS (12.0 for Windows,
Chicago, Il, USA).
Results
Descriptive statistics for strength, range of motion, self-
report upper extremity function and upper-limb func-
tional performance are included in Tables 1, 2, 3 and 4.
The results are stratified by age category, gender, and hand
dominance.
Strength
Gender by age interaction effects were observed for both
internal and external rotations strength (F > 3.50; P <
0.03; dominant and non-dominant sides). Therefore, the
effects of both gender and age were evaluated separately.
For all age categories, men were significantly (approxi-
mately 2 times) stronger than women (P < 0.001; Table

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2). For men, there was a marked decrease in mean
strength in the over-60 age category (Table 2). ANOVA
revealed that this decrease was significant in the men over
60 years of age as compared to younger age group for
external rotation strength, dominant and non-dominant
sides, and for internal rotation strength, but only for the
non-dominant side (P < 0.001) (Table 2). This effect was
not observed in women. For all mean strength measure-
ments, men were strongest in the 40–59 age category,
while women were strongest in the 18–39 age category.
Across all subjects, the dominant side was significantly
stronger than the non-dominant side for internal (t =
3.142; P = 0.002) and external (t = 2.173; P = 0.032) rota-
tion (Table 2). However, the mean differences between
dominant/non-dominant sides were small and may not
be clinically relevant (mean differences: 2.2 ± 8.0 Nm or
Table 2: Shoulder strength (in Nm) in men and women by age
Internal
Rotation (D)
Internal
Rotation (ND)
External Rotation (D)External
Rotation (ND)
Mean* Mean*Mean*Mean*
Men
18–39
40–59
60+
45.2 ± 15.8¶ (n = 60)
46.8 ± 16.5¶ (n = 25)
50.5 ± 16.7¶ (n = 18)
37.1 ± 10.1¶ (n = 17)
42.8 ± 15.6¶ (n = 60)
45.7 ± 15.6¶,a (n = 25)
49.4 ± 15.5¶,b (n = 18)
31.5 ± 8.8¶,a, b (n = 17)
33.6 ± 11.3¶ (n = 81)
33.6 ± 9.0¶,a (n = 42)
40.0 ± 11.8¶,b (n = 21)
25.9 ± 11.2¶,a, b (n = 18)
34.0 ± 9.9¶ (n = 60)
35.8 ± 9.5¶,a (n = 25)
38.6 ± 8.6¶,b (n = 18)
26.5 ± 7.7¶,a, b (n = 17)
Women
18–39
40–59
60+
20.7 ± 7.6¶ (n = 71)
23.2 ± 9.0¶ (n = 28)
18.8 ± 5.7¶ (n = 31)
19.8 ± 7.1¶ (n = 12)
18.7 ± 6.6¶ (n = 71)
21.0 ± 7.2¶ (n = 28)
17.6 ± 5.6¶ (n = 31)
16.2 ± 6.3¶ (n = 12)
17.0 ± 4.8¶ (n = 88)
17.2 ± 5.0¶ (n = 43)
17.5 ± 3.7¶ (n = 32)
14.8 ± 5.9¶ (n = 13)
16.6 ± 5.2¶ (n = 71)
17.5 ± 5.7¶ (n = 28)
16.0 ± 2.9¶ (n = 31)
15.8 ± 8.3¶ (n = 12)
Total
18–39
40–59
60+
31.9 ± 17.1§ (n = 131)
34.3 ± 17.6 (n = 53)
30.5 ± 18.9 (n = 49)
30.0 ± 12.4 (n = 29)
29.7 ± 16.7§ (n = 131)
32.6 ± 17.2 (n = 53)
29.3 ± 18.6 (n = 49)
25.1 ± 10.9 (n = 29)
24.9 ± 11.9§ (n = 169)
25.3 ± 11.0 (n = 85)
26.4 ± 13.7 (n = 53)
21.3 ± 10.8 (n = 31)
24.6 ± 11.6§ (n = 131)
26.2 ± 11.9 (n = 53)
24.3 ± 12.3 (n = 49)
22.1 ± 9.5 (n = 29)
Significant differences between: ¶men and women; §dominant and non-dominant sides; a18–39 and over-60 age categories; b40–59 and over-60 age
categories. * Mean ± 1 SD
Abbreviations: D, Dominant arm; ND, Non-dominant arm.
Table 3: Range of motion (in degrees) in men and women by age.
Supine Sitting
Internal
Rotation
(D)
Internal
Rotation (ND)
External
Rotation
(D)
External
Rotation (ND)
External
Rotation
(D)
External
Rotation (ND)
Mean*Mean*Mean* Mean*Mean* Mean*
Men (n = 58)
18–39 (n = 25)
40–59 (n = 17)
60+ (n = 16)
64.3 ± 16.0
61.5 ± 1 5.3
69.8 ± 14.3
62.7 ± 18.1
67.1 ± 16.1
64.0 ± 13.4
72.8 ± 16.7
66.0 ± 18.5
87.8 ± 10.1
90.7 ± 9.5
86.0 ± 9.0
85.1 ± 11.3
85.1 ± 12.6
87.0 ± 13.1
84.3 ± 12.6
83.1 ± 12.2
65.2 ± 15.0
66.2 ± 14.6
60.5 ± 15.4
69.0 ± 14.9
64.0 ± 16.6¶
66.4 ± 16.4
58.7 ± 19.9¶
65.9 ± 11.9
Women (n = 72)
18–39 (n = 30)
40–59 (n = 31)
60+ (n = 11)
70.1 ± 19.1
69.3 ± 17.2
73.9 ± 18.3
61.5 ± 24.7
70.3 ± 18.5
67.7 ± 15.5
74.5 ± 18.1
65.2 ± 25.6
89.5 ± 11.5
91.5 ± 12.4
89.9 ± 10.2
82.7 ± 10.5
86.2 ± 13.3
87.3 ± 13.1
87. 2 ± 11.6
80.5 ± 17.5
69.3 ± 14.4
68.0 ± 13.4
73.1 ± 14.9
66.6 ± 17.9
71.6 ± 17.5¶
70.9 ± 19.5
73.9 ± 16.5¶
67.2 ± 14.8
Total (n = 130)
18–39 (n = 55)
40–59 (n = 48)
60+ (n = 27)
67.5 ± 18.0
65.8 ± 16.7
72.5 ± 17.0
62.2 ± 20.6
68.9 ± 17.5
66.0 ± 14.5
73.9 ± 17.5
65.7 ± 21.2
88.7 ± 10.9§
91.1 ± 11.1a
88.5 ± 9.9
84.1 ± 10.9a
85.7 ± 13.0§
87.2 ± 13.0
86.1 ± 11.9
82.0 ± 14.3
67.7 ± 14.8
67.3 ± 13.8
68.2 ± 16.2
68.0 ± 15.9
68.1 ± 17.5
68.8 ± 18.1
68.3 ± 19.1
66.4 ± 12.9
Significant differences between: ¶men and women; §dominant and non-dominant sides; a18–39 and over-60 age categories; b40–59 and over-60 age
categories. * Mean ± 1 SD.

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6.9% for internal rotation; 1.0 ± 5.2 Nm or 4.0% for exter-
nal rotation). Across all subjects, the external/internal
rotation strength ratio was 0.88 ± 0.39 for the dominant
arm and 0.89 ± 0.25 for the non-dominant arm. For the
dominant side, the ratio was significantly lower (F =
3.435; P = 0.035) in the over-60 age category (ratio = 0.76
± 0.23) compared to the 40–59 age category (ratio = 0.99
± 0.47) suggesting a relatively greater loss of external rota-
tion strength in the older group. Gender and dominance
had no significant effects on the external/internal rotation
strength ratio. There were significant correlations between
shoulder rotation strength (internal and external rotation,
dominant and non-dominant sides) and external rotation
range of motion in the sitting position (r ranges from -
0.22 to -0.32; P < 0.05) (Table 5).
Range of motion
There were no interaction effects between age and gender
for range of motion in either supine or sitting positions.
Gender effects were observed for seated external rotation
range of motion for the non-dominant side (F = 4.725; P
= 0.03), showing that women had significantly more
range of motion than men for seated external rotation (t =
2.545; P = 0.012), especially in the 40–59 age category (t
= 2.967; P = 0.006) (Table 3). Age effects were observed in
the dominant side for external and internal rotation in the
supine position (F > 4.000; P < 0.05). ANOVA reveals the
effects were only significant in external rotation (P =
0.016), showing that across all subjects the over-60 age
category experienced a significant decrease of range of
motion as compared to the 18–39 age category (Table 3).
Across all subjects, the dominant side had greater range of
motion in external rotation in the supine position (t =
3.242; P = 0.002) as compared to the non-dominant side.
Again, the differences between dominant/non-dominant
sides were small (mean differences for supine external
rotation: 3.0° ± 10.6° or 3.4%). There was significant neg-
ative correlation between age and external rotation range
of motion (dominant side) in the supine position (r = -
0.22, P < 0.011) (Table 5).
Table 4: FIT-HaNSA (in seconds) in men and women by age.
Task 1 Task 2 Task 3
Mean SDMeanSD MeanSD
Men (n = 40)
18–39 (n = 29)
40–59 (n = 8)
60+ (n = 3)
298.3
300.0
300.0
276.7
11.1
0.0
0.0
40.4
248.6
249.3
282.5
151.6
72.1
63.9
49.5
129.6
288.0
292.1
283.0
261.7
34.9
29.3
48.1
47.8
Women (n = 85)
18–39 (n = 69)
40–59 (n = 13)
60+ (n = 3)
294.9
295.4
290.9
300.0
21.8
19.8
32.8
0.0
239.7
230.6
274.0
300.0
82.1
84.6
62.8
0.0
282.7
279.9
293.8
300.0
44.5
48.6
15.8
0.0
Total (n = 125)
18–39 (n = 98)
40–59 (n = 21)
60+ (n = 6)
296.0
296.8
294.4
288.3
19.1
16.7
25.8
28.6
242.6§
236.2
277.2
225.8
78.8
79.2
56.9
115.5
284.4§¶
283.5
289.7
280.9
41.6
44.0
31.4
36.8
Significant differences compared to:§ Task 1; ¶Task 2.
Table 5: Correlation between age, range of motion and strength.
Range of motion
Supine Sitting
Age Internal
Rotation
(D)
Internal
Rotation
(ND)
External
Rotation
(D)
External
Rotation
(ND)
External
Rotation
(D)
External
Rotation
(ND)
Age
----0.05
(n = 130)
-0.09
(n = 128)
0.03
(n = 130)
-0.07
(n = 128)
-0.22*
(n = 130)
-0.05
(n = 128)
-0.15
(n = 130)
-0.04
(n = 128)
-0.01
(n = 196)
-0.28**
(n = 129)
-0.08
(n = 131)
-0.32**
(n = 129)
Strength Internal
Rotation
(D)
Internal
Rotation
(ND)
External
Rotation
(D)
External
Rotation
(ND)
-0.14
(n = 131)
-0.17
(n = 131)
-0.16
(n = 128)
-0.12
(n = 128)
-0.03
(n = 128)
0.01
(n = 128)
-0.23**
(n = 129)
-0.27**
(n = 129)
-0.09
(n = 169)
-0.07
(n = 130)
-0.03
(n = 130)
-0.01
(n = 130)
0.04
(n = 130)
-0.22*
(n = 131)
-0.28**
(n = 131)
-0.16
(n = 131)
-0.13
(n = 128)
-0.09
(n = 128)
-0.05
(n = 128)
0.05
(n = 128)
-0.23*
(n = 129)
-0.28**
(n 129)
* Significant at P < 0.05; ** Significant at P < 0.01.
Abbreviations: D, Dominant arm; ND, Non-dominant arm

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Functional performance
For functional performance, no interaction, age or gender
effects were observed. Age and gender did not predict
scores of any of the three tasks or of the total score of the
FIT-HaNSA. Across all subjects, the performance of task I
(level reaching) was significantly better than on the tasks
II (overhead reaching) and III (sustained overhead work),
and task III was performed significantly better than task II
(Table 4). There were significant correlations between the
FIT-HaNSA total score and the DASH scores (r = -0.31, P
< 0.001).
Self-report upper extremity function
Self-report of shoulder and upper extremity function
revealed no obvious trends, except for the SST for which
age effects were observed (F = 4.492; P = 0.013). There-
fore, age categories were compared across all subjects
using ANOVA. The results show that SST scores were sig-
nificantly decreased in the over-60 age category when
compared to the 18–39 and 40–59 age categories (P <
0.011) (Table 1). There was also a significant correlation
between age and SST scores (r = -0.20, P < 0.05) (Table 6).
There were no significant correlations between self-report
function and range of motion or strength. There was a sig-
nificant correlation between the DASH and WORC (r =
0.19, P = 0.03). The SST was not correlated with the two
others questionnaires.
Discussion
This study provides comparative data for strength, range
of motion, functional performance and self-reported
function in persons who state they have no shoulder pain
or disorders. The data is sparse for the over-60 group since
it was difficult to find people in this age group who could
fit the criteria. This reflects the high prevalence of shoulder
problems in advancing age groups [33-35]. Random sam-
pling to provide normative data from the population
would be expected to include a high rate of people with
shoulder pathology [35], therefore, the difference
between unaffected and normative data should widen as
the age of interest increases.
Results for shoulder rotation strength were mostly consist-
ent with the findings of several previous papers that tested
isometric strength, showing that on average, men are
stronger than women [11,13-15]. Some differences, how-
ever, were observed. In men, strength significantly
decreased in the over-60 age category. This differs slightly
from the findings of Hughes et al. who suggest that
strength declines linearly with age [14]. One possible
cause of the decline in strength with aging is a decreased
muscle mass, which may affect men (who have typically
more muscle mass) more than women. Our data shows
that there is a drop-off in strength around 60 years of age.
Since retirement age is generally between 60 and 65, this
might suggest that activity level is a contributing cause.
Women appear to be strongest in their childbearing years
(ages 18–39), which may be related to the type and quan-
tity of activities required at this portion of their lifespan.
Kim et al. [35] also found less age related decline in
women as compared to men when evaluating four sub-
groups aged 40 years and older. It is clear that there is wide
variation in strength in the younger categories, and that
this variation decreases considerably in the eldest cate-
gory; for the 18–39 category, the standard deviation for
strength measurements ranges from 11.0 to 17.9, while in
the over-60 category, the range is only from 9.5 to 12.4.
This reduced variability may reflect a reduced contribu-
tion of occupation related inter-individual differences in
the over-60 group.
Kim et al. [35] noted that 20% of subjects aged between
60–69 years, and 41% of subjects older than 70 years,
claiming to be asymptomatic had a rotator cuff tear on
ultrasonography. Although the numbers in the study sub-
groupps were small, the authors reported no significant
Table 6: Correlation between self-reported function and age, range of motion and strength.
DASHSSTWORC
Age
Strength
0.03 (n = 255)
-0.16 (n = 130)
-0.13 (n = 130)
-0.12 (n = 130)
-0.11 (n = 130)
0.02 (n = 127)
-0.03 (n = 127)
-0.01 (n = 127)
-0.02 (n = 127)
0.12 (n = 193)
0.13 (n = 128)
0.20* (n = 130)
0.06 (n = 130)
0.07 (n = 130)
0.11 (n = 130)
0.15 (n = 130)
0.03 (n = 127)
0.00 (n = 127)
0.02 (n = 127)
-0.08 (n = 127)
0.16 (n = 128)
0.03 (n = 128)
0.05 (n = 129)
-0.05 (n = 129)
-0.02 (n = 129)
0.07 (n = 129)
0.00 (n = 129)
-0.06 (n = 126)
-0.03 (n = 126)
-0.13 (n = 126)
-0.02 (n = 126)
-0.10 (n = 127)
-0.02 (n = 127)
Internal Rotation (D)
Internal Rotation (ND)
External Rotation (D)
External Rotation (ND)
SupineROM Int. Rot. (D)
Int. Rot. (ND)
Ext. Rot. (D)
Ext. Rot. (ND)
Ext. Rot. (D)
Ext. Rot. (ND)
Sitting
* Significant at P < 0.05.
Abbreviations: D, Dominant arm; ND, Non-dominant arm; ROM, Range of Motion; Int.
Rot., Internal Rotation; Ext. Rot., External Rotation.

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loss of external rotation or abduction strength in partial or
full-thickness rotator cuff tear; whereas a loss of abduction
strength was observed with a large-to-massive full thick-
ness tear. We did not perform imaging to define cuff status
but recruited individuals reporting no shoulder pain or
disability.
Muscle bulk may contribute to differences in range of
motion between men and women. There were moderate
negative correlations (-0.28 to -0.32) between strength
and sitting range of motion. Due to testing position, mus-
cle bulk may limit flexibility in stronger individuals. This
interference would be eliminated in the supine testing due
to the abduction of the humerus to 90°. Overall, there
was a reduction in external rotation range of motion in
the over-60 age category, while there was a negative corre-
lation between age and external rotation range of motion.
Our results are consistent with other studies that have
shown that some shoulder range of motion decreases with
aging [17,18]. However, in the study performed by Barnes
et al., passive and active internal rotation at 90° of abduc-
tion was not affected by aging [17].
It has been suggested that isometric strength testing may
provide more useful data in older patients with rotator
cuff repairs than isokinetic tests [36]. Therefore, we
elected to only perform isometric testing. Only few studies
have reported normative data for external and internal
rotational strength in the plane of the scapula [14,15].
This position has been described by Greenfield et al. as
being clinically significant because it optimizes the
length-tension relationship of the shoulder abductors and
rotators and creates a significant degree of conformity
between the humeral head and the glenoid [37]. Position
can affect strength scores obtained so data comparisons
should be made across similar test procedures.
The findings on the relationships between self-report
scales in this study are counter-intuitive and incongruent
with the results obtained in patient samples. One would
expect there to be strong correlations between the self-
report instruments because they all measure similar con-
structs and because strong correlations have been reported
across different shoulder pathologies (0.88 <r < 0.91)
[20]. Weak correlations, however, were observed (0.01 <r
< 0.19). This may be due to attribute and scale factors.
Firstly, the self-report scales were not designed to detect
differences across a range of "normal" ability. Since a
small range of the spectrum (minimal disability) was
sampled in asymptomatic subjects, correlations obtained
would not accurately portray the relationship across the
full spectrum. Similarly, whereas a moderate relationship
has been observed between self-reported function and
measured of physical impairments (strength or range of
motion) in studies assessing pathological groups, we
found a weak relationship (0.18 < r < 0.56) [20]. This sug-
gests that there is a wide variation in strength and range of
motion that allows normal people to perform their nor-
mal tasks of daily life.
Unlike the DASH or WORC, a significant correlation
between age and the SST was observed (r = -0.202). The
SST contains a wider range of items, including more diffi-
cult items like questions on activities requiring muscle
strength and power, such as lifting 3.6 kg (8 pounds), car-
rying 9.1 kg (20 pounds) or tossing a softball over-hand
18.3 m (20 yards). It also requires a yes/no response
which may be more discriminative. The DASH asks about
some higher level activities in a more indirect way saying
"recreational activities which you take some force or
impact through your arm, shoulder or hand". Perceptions
or expectations around what this means to an individual
may change overtime (response shift). Furthermore, most
items on the DASH are less demanding activities of daily
life tasks and the response is a 5-point scale so that
changes in capability may be measured differently than
on the SST. Similarly, the WORC also contains few specific
difficult tasks and it measures on a 10-cm VAS scale. Thus,
the weak relationships between the SST and the DASH or
WORC may reflect their different approaches to measur-
ing shoulder function.
The FIT-HaNSA is an alternative means to assess func-
tional status that evaluates task performed in a timed test
[23]. The FIT-HaNSA requires that subjects possess
enough shoulder muscle endurance and joint range of
motion to perform three different types of task. As with
self-reported function, no significant correlations were
observed between strength/range of motion and func-
tional performance. This may be related to the spectrum
issue. However, the FIT-HaNSA contains tasks more
related to muscle endurance than to muscle strength.
Therefore, future studies should look at the relationships
between muscle endurance and the FIT-HaNSA. It is not
surprising that no correlation with rotational range of
motion and FIT-HaNSA were established as the test
requires most of the movement in the frontal plane. The
ranges of motion observed in the subjects recruited (the
minimum was 32° in internal and 38° in external rota-
tion) were more than enough to enable the subjects to
perform the three tasks of the FIT-HaNSA. Unfortunately,
shoulder elevation (flexion, scaption or abduction)
ranges of motion were not evaluated in this study, but
might be expected to have a bigger impact on the FIT-
HaNSA scores.
The mean scores on the DASH index in this study fall
below the normative values quoted in the study published
by Hunsaker et al. [21]. For example, DASH normal scores
were 10.1 ± 14.7 in the study by Hunsaker et al. [21], and

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1.8 ± 2.9 in the present study. This suggests that we were
successful in obtaining subjects with no upper extremity
pathology for our study, and confirms our assumption
that "normative" data is influenced by the high rates of
shoulder pathology at older ages. This is important when
considering "recovery" for older persons who previously
were unaffected by shoulder pathology. While their scores
may end up close to population norms, this might still
represent a substantial loss from their preinjury level. We
were easily able to recruit younger age cohorts, and there
were large numbers of older people who were willing to
be tested but did not qualify for the study criteria. In fact,
the smaller size of this subgroup is a limitation in this
study and suggests that future research on pain free shoul-
der in the elderly will be a challenge. Thus, we called our
data unaffected comparison data, not normative data,
since it reflects a non-pathologic state that is not "normal"
in older age groups. The small number of older subjects
could have also been detrimental in detecting differences
across age categories.
Conclusion
This paper yields several important facts about the rela-
tionship among rotational strength, range of motion,
functional performance and self-reported function in peo-
ple with unaffected shoulders and can serve as a valuable
clinical resource for comparison with a patient popula-
tion. First, there is indeed a decline in strength with aging,
especially for the men. This decline, however, does not
appear linear, but is more notable over the age of 60.
There is more variation in strength within younger age
subgroups than within the older subgroups. Second, there
is a significant negative correlation between strength and
sitting range of motion. In the sitting position, women are
more flexible than men in external rotation for the 40–59
age categories. Third, there is no significant relationship
between self-reported function and strength/range of
motion over a narrow range of normal function in asymp-
tomatic individuals. Finally, measured functional per-
formances also not correlated with strength/range of
motion in asymptomatic individuals; however, it is corre-
lated with self-reported function (DASH). The SST may be
more discriminative to age related changes in shoulder
function than the DASH or WORC. Further research is
needed to expand upon the interactions delineated in this
paper, and to further understand the relationship between
different impairment and disability outcome measures.
This study emphasizes that both young and older individ-
uals who present as asymptomatic experience very low
levels of disability; but the older individuals scores are
much better than population "norms". Selection of com-
parative data should consider that scores from patients
with similar procedures/injuries, or individuals without
pathology are different, both conceptually and quantita-
tively, from a "normal" score which reflects the overall
rate of functional disability existing in a population or
subgroup.
Abbreviations
ANOVA: Analysis of Variance; DASH: Disabilities of the
Arm, Shoulder, and Hand; FIT-HaNSA: Functional per-
formance of the upper extremity and neck; ICC: Intraclass
Correlation Coefficient; Nm: Newton metre; SST: Simple
Shoulder Test; WORC: Western Ontario Rotator Cuff
index.
Competing interests
The authors declare that they have no competing interests.
Authors' contributions
JSR participated in the analysis and the interpretation of
data, conducted statistical analyses, and drafted the man-
uscript. JCM: designed the study, participated in the anal-
ysis and the interpretation of data, and drafted the
manuscript. KUB enrolled and tested subjects, and partic-
ipated in the revision of the manuscript. KF participated in
the development of the study question, enrolled subjects,
and participated in the revision of the manuscript. DD
participated in the development of the study question,
enrolled subjects, and participated in the revision of the
manuscript. GA participated in the development of the
study question, enrolled subjects, and participated in the
revision of the manuscript. All authors read and approved
the final manuscript.
Acknowledgements
The authors wish to thank Carol Fazekas, Tajedin Getahun, Ana-Maria
Marinescu, Kristie Roth, Prajyot Kumta and Jan Smith for their assistance
with subject recruitment and data collection. Joy MacDermid holds a New
Investigator Award from the Canadian Institutes for Health Research.
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