Overweight and obesity in young adults with patellofemoral pain: Impact on functional capacity and strength

Abstract

Purpose
: To (i) investigate the proportion of overweight/obesity in a cohort of young adults with patellofemoral pain (PFP) and (ii) explore the association of body mass index (BMI), body fat, and lean mass with functional capacity and hip and knee strength in people with PFP.

Methods
: We included a mixed-sex sample of young adults (18−35 years old) with PFP (n = 100). Measurements for BMI, percentage of body fat, and lean mass (assessed by bioelectrical impedance) were obtained. Functional capacity was assessed by the anterior knee pain scale (AKPS), plank test, and single-leg hop test. Strength of the knee extensors, knee flexors, and hip abductors was evaluated isometrically using an isokinetic dynamometer. The proportion of overweight/obesity was calculated based on BMI. The association between BMI, body fat, and lean mass and functional capacity and strength was investigated using partial correlations, followed by hierarchical regression analysis, adjusted for covariates (sex, bilateral pain, and current pain level).

Results
: A total of 38% of our cohort had their BMI categorized as overweight/obese. Higher BMI was associated with poor functional capacity (ΔR² = 0.06−0.12, p ≤ 0.001) and with knee flexion strength only (ΔR² = 0.04, p = 0.030). Higher body fat was associated with poor functional capacity (ΔR² = 0.05−0.15, p ≤ 0.015) and reduced strength (ΔR² = 0.15−0.23, p < 0.001). Lower lean mass was associated with poor functional capacity (ΔR² = 0.04−0.13, p ≤ 0.032) and reduced strength (ΔR ² = 0.29− 0.31, p < 0.001).

Conclusion
: BMI, body fat, and lean mass should be considered in the assessment and management of young people with PFP because it may be detrimental to function and strength.

Full text

Original article
Overweight and obesity in young adults with patellofemoral pain:
Impact on functional capacity and strength
Amanda Schenatto Ferreira
a,
*, Benjamin F. Mentiplay
b
, Bianca Taborda
a
,
Marcella Ferraz Pazzinatto
a,b
,F

abio M
ıcolis de Azevedo
a
, Danilo de Oliveira Silva
a,b
a
Department of Physiotherapy, School of Science and Technology, Sao Paulo State University (UNESP), Presidente Prudente, 19060-900, Brazil
b
La Trobe Sport and Exercise Medicine Research Centre, School of Allied Health, Human Services and Sport, La Trobe University, Melbourne,
VIC 3086, Australia
Received 8 July 2020; revised 5 October 2020; accepted 29 October 2020
2095-2546/Ó2021 Published by Elsevier B.V. on behalf of Shanghai University of Sport. This is an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/by-nc-nd/4.0/)
Abstract
Purpose: To (i) investigate the proportion of overweight/obesity in a cohort of young adults with patellofemoral pain (PFP) and (ii) explore the
association of body mass index (BMI), body fat, and lean mass with functional capacity and hip and knee strength in people with PFP.
Methods: We included a mixed-sex sample of young adults (1835 years old) with PFP (n= 100). Measurements for BMI, percentage of body
fat, and lean mass (assessed by bioelectrical impedance) were obtained. Functional capacity was assessed by the Anterior Knee Pain Scale, plank
test, and single-leg hop test. Strength of the knee extensors, knee flexors, and hip abductors was evaluated isometrically using an isokinetic
dynamometer. The proportion of overweight/obesity was calculated based on BMI. The association between BMI, body fat, and lean mass and
functional capacity and strength was investigated using partial correlations, followed by hierarchical regression analysis, adjusted for covariates
(sex, bilateral pain, and current pain level).
Results: A total of 38% of our cohort had their BMI categorized as overweight/obese. Higher BMI was associated with poor functional capacity
(DR
2
= 0.060.12, p0.001) and with knee flexion strength only (DR
2
= 0.04, p= 0.030). Higher body fat was associated with poor functional
capacity (DR
2
= 0.050.15, p0.015) and reduced strength (DR
2
= 0.150.23, p<0.001). Lower lean mass was associated with poor func-
tional capacity (DR
2
= 0.040.13, p0.032) and reduced strength (DR
2
= 0.290.31, p<0.001).
Conclusion: BMI, body fat, and lean mass should be considered in the assessment and management of young people with PFP because it may be
detrimental to function and strength.
Keywords: Body fat distribution; Body mass index; Patellofemoral pain syndrome; Torque
1. Introduction
Patellofemoral pain (PFP) is characterized by insidious
onset of diffuse anterior knee pain, exacerbated by activities
that load the patellofemoral joint (e.g., running, climbing
stairs, squatting).
1
PFP has an estimated annual prevalence of
23% in the general population and up to 35% prevalence in
sporting populations.
2
PFP is associated with poor quality of
life, poor physical health, and poor psychological health.
35
Furthermore, there has been speculation that PFP is a precursor
to patellofemoral osteoarthritis (OA).
68
Numerous biomechanical, anatomical, and psychological
factors have been linked to PFP.
1,911
Specifically, impaired
knee strength is a risk factor for people with PFP,
12
and
impaired functional capacity predicts poor outcomes for peo-
ple with PFP after rehabilitation.
13,14
Other potential factors
associated with PFP that have received less attention are body
composition measures. Findings from a systematic review
indicates that young adults with PFP have greater body mass
index (BMI)
15
than pain-free controls. Greater BMI has also
been reported as a clinical predictor of poor long-term out-
comes in people with PFP.
16
Despite compelling evidence
indicating that high BMI is detrimental to people with PFP, its
impact on functional capacity and strength in this population
has never been explored. Moreover, other measures of body
composition (e.g., body fat and lean mass), which seem to pro-
vide additional and more accurate implications of overweight
and obesity on an individual’s health status compared to BMI
alone,
17,18
have also never been explored in this population.
Peer review under responsibility of Shanghai University of Sport.
*Corresponding author.
E-mail address: amandaschenatto_@outlook.com (A.S. Ferreira).
https://doi.org/10.1016/j.jshs.2020.12.002
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Available online at www.sciencedirect.com
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Overweight and obesity are associated with impaired
functional capacity and knee strength in people with knee
OA,
1822
with body fat and lean mass presenting a higher
association (ΔR
2
= 0.162 and
Δ
R
2
= 0.093, respectively) with
impaired functional capacity than BMI (ΔR
2
= 0.005).
18
Although these findings are mostly related to the tibiofemoral
joint (i.e., tibiofemoral OA), previous studies
23
have reported
that overweight and obesity also have deleterious effects on
patellofemoral OA, likely via metabolic factors (i.e., increased
leptin due to obesity has been associated with reduced patellar
cartilage volume)
24
and/or mechanical factors (i.e., increased
loading by obesity may also affect patellar cartilage and its
biomechanical properties).
25,26
Additionally, studies have
reported that a weight loss of 10% or higher led to clinically
important improvements in pain, functional capacity, and
knee strength in people with knee OA (both tibiofemoral and
tibiofemoral plus patellofemoral OA).
2730
However, as
highlighted in a recent editorial, interventions targeting weight
loss do not exist in the PFP literature.
31
The detrimental effects
of overweight and obesity have been extensively explored in
several other musculoskeletal conditions.
18,3234
However, it
remains underexplored in PFP. More research is needed to
understand the impact of overweight and obesity on clinically
important PFP outcomes, such as functional capacity and
strength. Considering that overweight and obesity are modifi-
able factors, our findings could provide novel insights toward
changing traditional rehabilitation of PFP.
35
Therefore, the
aims of our study are twofold: (i) to investigate the proportion
of overweight and obesity in a cohort of young adults with
PFP and (ii) to explore the association of BMI, body fat, and
lean mass with functional capacity and knee strength in young
adults with PFP.
2. Methods
This cross-sectional study was reported according to the
Strengthening the Reporting of Observational Studies in
Epidemiology guideline recommendations.
36
The study was
approved by the University Ethics Committee (No.
1.484.129), and each participant provided informed written
consent prior to data collection.
2.1. Recruitment
Participants were recruited from the community between
October 2018 and November 2019 via advertisements at uni-
versities and fitness centers and via posts on social media. Par-
ticipants were between 18 and 35 years of age. Eligibility
criteria were assessed by a physiotherapist (with >7 years of
experience in assessing people with PFP). Eligibility criteria
included (i) anterior knee pain in at least one limb provoked
by at least two of the following activities: running, walking,
hopping, landing, squatting, negotiating stairs, kneeling, or
prolonged sitting,
1
(ii) insidious onset of symptoms with a
duration of at least 3 months, and (iii) anterior knee pain in the
previous month of at least 30 mm on a 100-mm visual ana-
logue scale.
37
Exclusion criteria included the following: a his-
tory of patellar subluxation, a history of surgery on any lower
limb joint, the presence of meniscal injury
38
or ligament insta-
bility,
39
and self-reported back, hip, ankle, or foot pain. To
control for potential carry-over effects from previous treat-
ments that might influence the outcomes assessed, those who
had received acupuncture, physiotherapy, or any other treat-
ment for PFP during the preceding 6 months were also
excluded from our study. Participants were asked to refrain
from taking, in the 7 days prior to data collection, any medica-
tions and to avoid participating in any type of physical activity
they were unaccustomed to.
2.2. Sample size calculation
An a priori sample size calculation was performed using
G*Power Statistical Power Analysis Software V3.1 (Uni-
versit€
at D€
usseldorf, D€
usseldorf, Germany). In our pilot study,
with data drawn from 30 participants with PFP, BMI uniquely
explained 4.8% of the variance in the single-leg hop test while
the covariates explained 39.0%. We chose the single-leg hop
test to power our study because it presented the smallest DR
2
among all variables. We estimated that we would need at least
94 participants to detect a ΔR
2
of 0.048 with 80% of power
and an alevel of 0.05, using 4 predictor variables.
2.3. Overview of the experimental approach
A total of 100 young adults with PFP were invited to attend
a one-day assessment at the Sao Paulo State University. BMI,
percentages of body fat and lean mass, functional capacity
(measured by the Anterior Knee Pain Scale (AKPS), plank
test, and single-leg hop test), and strength measures (peak iso-
metric knee extension, knee flexion, and hip abduction torque)
were obtained. After data collection completion, the propor-
tion of overweight and obesity in our sample (based on BMI)
was calculated and described as a percentage of the entire
cohort (Aim 1). Then, we used partial correlation and hierar-
chical regression analysis to investigate the relationship of
BMI, body fat, and lean mass with functional capacity and
strength in young adults with PFP (Aim 2). All analyses were
adjusted for covariates (sex, bilateral pain, and current pain
level) on the basis of previously reported associations
4042
or
plausible hypotheses. Fig. 1 shows in detail the experimental
design of our study.
2.4. Participant characteristics
Demographics (age, sex, height, and body mass) were
obtained, along with duration of symptoms (months) and pres-
ence of bilateral pain. Height and body mass were assessed
with participants wearing light clothing and no shoes. Body
mass was measured to the nearest 0.1 kg, and height was
measured to the nearest 0.1 cm using a calibrated scale with a
stadiometer (Welmy 110 CH; WelmyÒ, Sao Paulo, Brazil).
Body mass and height were used to calculate BMI (kg/m
2
).
Before data collection, all participants rated their current
knee pain intensity on a 0100 visual analogue scale, with 0
indicating no pain and 100 indicating the worst pain
possible.
37
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Please cite this article as: Amanda Schenatto Ferreira et al., Overweight and obesity in young adults with patellofemoral pain: Impact on functional capacity and strength, Journal of
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2 A.S. Ferreira et al.

2.5. Bioelectrical impedance analysis
Body fat and lean mass were measured using a bioelectrical
impedance analyzer (Omron HBF 514C; Omron Healthcare
Co., Kyoto, Japan). The device uses 8 electrodes in a tetrapolar
arrangement and requires participants to stand on metal foot-
pads in bare feet and hold a pair of electrodes fixed on the dis-
play unit, with arms extended in front of their chest. The
manufacturers’ valid and reliable equations
43
were used to pre-
dict body fat and lean mass (expressed as a percentage of total
body mass). Due to the inclusion of a mixed-sex sample with
wide ranges of body mass, body fat, and lean mass were
reported as a percentage to facilitate the interpretation of
results. Participants were instructed to avoid alcohol and caf-
feine consumption for 24 h prior to measurement, to avoid vig-
orous exercise for 12 h prior to measurement, and to avoid
food and beverages for 2 h prior to measurement.
2.6. Functional capacity
Self-reported functional capacity was assessed by the
AKPS. Objective functional capacity was assessed by the
plank test and single-leg hop test in a randomized order. Data
collection for all lower limb assessments was performed in the
symptomatic leg or most symptomatic leg (in case of bilateral
symptoms).
5
The AKPS is a valid and reliable 13-item questionnaire
used to assess functional capacity of people with PFP; the
overall score ranges from 0 (maximum functional limitation)
to 100 (no functional limitation).
37
To perform the plank test, participants assumed a prone
position supported by their forearms and feet, with the should-
ers and elbows flexed at 90˚. They were instructed to raise their
pelvis from the floor, maintaining a straight line from head to
ankles, and to hold this static position as long as possible. If
necessary, verbal instructions were given to correct partic-
ipants’ positioning. The evaluator ended the test when partici-
pants were no longer able to maintain the proper position after
2 warnings or when the participant ended it due to fatigue. Par-
ticipants performed a single trial, and the test duration was
recorded with a stopwatch.
44
To perform the single-leg hop test, the participant stood on
the tested leg with the heel positioned on a marked line and
with the other leg lifted from the floor by flexing the contralat-
eral knee. The participants were told to hop as far as possible,
keeping their arms behind their back, taking off and landing
on the same foot, and maintaining their balance for about 2 s
after landing. The hop distance (cm) was measured, with a
measuring tape that was affixed to the floor, from the heel in
the starting position to the heel in the landing position. A hop
was considered successful when the participant was able to
maintain balance for at least 2 s after landing. A hop was con-
sidered unsuccessful when the participant touched the floor
with the contralateral lower extremity, lost balance, pushed
with the contralateral foot, or did not keep the hands behind
the back. Each participant was given 3 practice trials before
the test. Three successive trials were then recorded. One min-
ute of rest was provided between each trial. The average value
of the 3 trials was used for statistical analysis.
5
Fig. 1. Flowchart describing the experimental approach. AKPS = Anterior Knee Pain Scale; BMI = body mass index; PFP = patellofemoral pain; WHO = World
Health Organization.
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Overweight in patellofemoral pain 3

Before the strength tests were administered, participants
were given a minimum of a 10-min rest after performing the
functional tests (plank test and single-leg hop test) in order to
avoid pain summation and limit neuromuscular fatigue. Addi-
tionally, participants were asked to perform the next test only
when they felt completely recovered from the previous one.
2.7. Knee and hip strength
After functional capacity assessments, maximal voluntary
isometric contractions (MVICs) of the knee extensors, knee
flexors, and hip abductors were measured using an isokinetic
dynamometer (Biodex System 4 Pro; Biodex Medical Systems
Inc., New York, NY, USA). Knee extensor and knee flexor
strength was assessed (Biodex System 4 Pro; Biodex Medical
Systems Inc.) in the same seating position, with the hips and
non-tested knee flexed at 90˚. Four straps were used to stabi-
lize the trunk, pelvis, and the tested limb. The dynamometer’s
rotational axis was aligned with the lateral epicondyle of the
femur, and the resistance pad was placed 5 cm above the lat-
eral malleolus. The MVICs of the knee extensors and flexors
were assessed with the tested limb at 60˚ of knee flexion.
45
Hip abductor strength was assessed (Biodex System 4 Pro;
Biodex Medical Systems Inc.) in a side-lying position, with the
tested limb on top of the non-tested limb, in neutral hip flexion/
extension and medial/lateral rotation alignment and with an
extended knee. Four straps were used to stabilize the trunk and
non-tested limb. The dynamometer’s rotational axis was aligned
with the hip joint center in the frontal plane of the tested limb,
and the resistance pad was placed on the lateral aspect of the dis-
tal thigh, 5 cm above the patella. MVICs for the hip abductors
were assessed with the tested limb at 30˚ of hip abduction.
45
The testing order for the muscle groups was randomized.
The assessor provided standardized verbal encouragement dur-
ing contractions to elicit maximal effort. Participants per-
formed 2 submaximal contractions of 6 s, with an interval of
30 s between trials for familiarization with each test position.
Then, 3 maximal isometric contractions of 6 s, with an interval
of 1 min between each trial, were performed in order to deter-
mine the MVIC for each muscle group. The highest peak tor-
que (N¢m) achieved in one of the 3 trials was used in the
statistical analysis.
45,46
2.8. Statistical analysis
Normality and variance homogeneity of data were tested
using the Shapiro-Wilk and Levene tests, respectively. Dura-
tion of symptoms and results of the plank test were non-nor-
mally distributed; therefore, results of the plank test were log
transformed before being included in the partial correlation
and hierarchical regression analyses. Descriptive statistics
were used to describe participant characteristics, body compo-
sition, functional capacity, and strength measures for the total
sample. Descriptive statistics were also described according to
BMI categories suggested by the World Health Organization
(WHO). Normally distributed variables were reported as
mean §SD, and non-normally distributed variables were
reported as median (interquartile range).
The first aim of our study was to determine the proportion
of overweight and obesity in our sample of young adults with
PFP. Overweight and obesity were defined based on the fol-
lowing BMI categories recommended by the WHO
47
: partici-
pants with a BMI of <18.5 kg/m
2
were categorized as
underweight, 18.5 kg/m
2
BMI <25 kg/m
2
were categorized
as normal weight, 25 kg/m
2
BMI <30 kg/m
2
were categorized
as overweight, and a BMI of 30 kg/m
2
were categorized as
obese. The proportion for each category was presented as a per-
centage of the entire cohort. No participants were underweight.
We also compared demographics and participant character-
istics, body composition, functional capacity, and knee and hip
strength measurements across all 3 BMI categories by running
a one-way analysis of variance or a KruskalWallis test.
Bonferroni’s post hoc test for multiple pairwise comparisons
was performed when overall differences were statistically sig-
nificant (p<0.05). Comparisons between BMI categories
for bilateral pain and sex were made using x
2
tests, with pair-
wise multiple comparisons using Bonferroni correction of
pvalues when overall differences were statistically signifi-
cant (p<0.05). These analyses are reported in Supplemen-
tary Table S1.
Our second aim was to explore the association of BMI,
body fat, and lean mass with functional capacity and strength
in young adults with PFP. We used partial correlation coeffi-
cients
48,49
to determine the relationship between independent
variables (BMI, body fat, and lean mass) and dependent varia-
bles (AKPS, plank test, single-leg hop test, and peak isometric
strength of the knee extensors, knee flexors, and hip abduc-
tors). All partial correlation analyses were adjusted for the
following covariates: (i) sex (previous studies have found sex
differences in the clinical presentation of people with
PFP
40,41
), (ii) bilateral pain (our sample included participants
with unilateral and bilateral symptoms; since it may influence
the outcomes, we included bilateral pain as a covariate), and
(iii) current pain level (PFP is characterized by intermittent
pain
42
that may highly influence the outcomes for each partici-
pant individually). The classification of correlation was
defined as small: r= 0.100.30 moderate: r= 0.310.50 and
strong: r= 0.511.00.
49
The variables that presented signifi-
cant correlations (p<0.05) were included in hierarchical
regression models.
Separate hierarchical regression models were used to deter-
mine the unique association of each measure of BMI, body fat,
and lean mass with each measure of functional capacity and
strength that presented significant correlations. All regression
models were also adjusted for covariates by first entering the
covariates (sex, bilateral symptoms, and current pain level)
into the hierarchical regression model (Model 1). Then,
either BMI, body fat, or lean mass was added into the model
(Model 2), which means that all changes in the results of the
regression models, from the first step to the second step, were
due to the insertion of the independent variable (either BMI,
body fat, or lean mass).
An alevel of 0.05 was set for all statistical tests. All analy-
ses were performed using the PASW Statistics software
(Version 18.0; SPSS Inc., Chicago, IL, USA).
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Please cite this article as: Amanda Schenatto Ferreira et al., Overweight and obesity in young adults with patellofemoral pain: Impact on functional capacity and strength, Journal of
Sport and Health Science (2021), https://doi.org/10.1016/j.jshs.2020.12.002
4 A.S. Ferreira et al.

3. Results
From October 2018 to November 2019, 100 young adults
with PFP (60 females and 40 males) were enrolled in our
study. Descriptive statistics for all variables are presented in
Table 1.
3.1. Proportion of overweight and obesity in young adults
with PFP
Of the 100 participants included in our study, 62% were
categorized as normal weight, 24% as overweight, and 14% as
obese.
3.2. Correlation coefficient findings
The partial correlation coefficients between variables of
interest are reported in Table 2. Significant negative correla-
tions were found for BMI with AKPS, plank, and single-leg
hop test (r=0.28 to 0.41, small to moderate). And a signifi-
cant positive correlation was found for BMI with knee flexion
strength (r= 0.22, small). No significant correlations were
found between BMI and knee extension and hip abductor
strength. Significant negative correlations were found for body
fat with AKPS, plank, single-leg hop test, and strength meas-
ures (r=0.25 to 0.49, small to moderate). Significant posi-
tive correlations were found for lean mass with AKPS, plank,
single-leg hop test, and strength measures (r= 0.22 to 0.57,
small to strong).
3.3. Regression models
The results of the hierarchical regression analyses are
reported in Tables 3,4, and 5. After adjusting for covariates,
BMI significantly explained 6% of the variance in AKPS
(p<0.001), 9% of the variance in plank (p<0.001), 12% of
the variance in single-leg hop test (p<0.001), and 4% of the
variance in knee flexion strength (p= 0.030) (Table 3).
After adjusting for covariates, body fat significantly
explained 5% of the variance in AKPS (p= 0.015), 10% of the
variance in plank (p<0.001), 15% of the variance in single-
leg hop test (p<0.001), 18% of the variance knee extension
strength (p<0.001), 15% of the variance in knee flexion
strength (p<0.001), and 23% of the variance in hip abductor
strength (p<0.001) (Table 4).
After adjusting for covariates, lean mass significantly
explained 4% of the variance in AKPS (p= 0.032), 11% of the
variance in plank (p<0.001), 13% of the variance in single-
leg hop test (p<0.001), 31% of the variance in knee extension
strength (p<0.001), 29% of the variance in knee flexion
strength (p<0.001), and 31% of the variance in hip abductor
strength (p<0.001) (Table 5).
4. Discussion
A total of 38% of our cohort had their BMI categorized
as overweight or obese. Higher BMI and body fat, and lower
lean mass, were associated with poor functional capacity,
even after adjusting for confounders such as sex, presence
Table 1
Characteristics of study participants.
Variable All sample BMI groups
Normal weight
(BMI = 18.524.9 kg/m
2
)
Overweight
(BMI = 2529.9 kg/m
2
)
Obese
(BMI 30 kg/m
2
)
Demographics
n100 62 24 14
Age (year) 24.11 §4.83 23.30 §4.60 24.16 §3.77 27.57 §6.13
Body mass (kg) 72.10 §15.48 64.25 §8.14 76.15 §9.93 99.90 §13.53
Height (cm) 168.88 §8.42 168.95 §8.03 169.14 §9.97 168.10 §7.82
BMI (kg/m
2
) 25.36 §4.78 22.55 §1.65 26.94 §1.31 35.10 §3.77
Bilateral pain (%) 57.0 54.8 70.8 42.8
Sex (females, %) 60.0 59.7 50.0 78.6
Worst pain level in the previous month (VAS) 50.70 §20.79 48.62 §21.59 50.83 §17.29 59.64 §21.61
Current pain level (VAS) 17.06 §21.45 12.19 §19.08 17.50 §17.87 37.89 §25.54
Duration of symptoms (months)
a
36 (1296) 36 (1194) 36 (1296) 54 (5123)
Body composition measures
Body fatbioimpedance (%) 31.13 §10.74 27.05 §8.91 32.54 §8.60 46.75 §5.44
Lean massbioimpedance (%) 31.36 §7.31 32.96 §7.45 31.51 §6.06 23.97 §3.30
Functional capacity measures
Functional capacity (AKPS) 78.44 §10.23 80.37 §9.47 78.91 §9.57 69.07 §10.07
Plank (s)
a
55 (3490) 60 (39100) 58 (4689) 22 (1532)
Single-leg hop test (cm) 90.11 §25.25 94.80 §23.61 93.89 §24.82 62.88 §14.78
Strength measures
Peak isometric knee extension (N¢m) 181.98 §62.87 178.70 §64.63 196.64 §63.65 171.42 §52.54
Peak isometric knee flexion (N¢m) 99.80 §33.02 96.06 §34.03 112.50 §32.36 94.59 §25.02
Peak isometric hip abduction (N¢m) 68.59 §23.74 69.38 §24.75 74.45 §22.74 55.08 §15.48
Note: Data are presented as mean §SD unless otherwise stated.
a
Data are presented as median (interquartile ranges).
Abbreviations: AKPS = Anterior Knee Pain Scale; BMI = body mass index; VAS = visual analogue scale.
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Please cite this article as: Amanda Schenatto Ferreira et al., Overweight and obesity in young adults with patellofemoral pain: Impact on functional capacity and strength, Journal of
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Overweight in patellofemoral pain 5

of bilateral pain, and current pain level. Additionally, higher
body fat and lower lean mass, but not BMI, were associated
with reduced knee and hip strength, even after adjusting for
confounders. Our study provides novel data related to body
fat and lean mass measures in young adults with PFP that
can be used to further advance assessment and treatment
strategies.
As noted, a BMI of 25 kg/m
2
was observed in 38% of our
cohort, indicating that overweight and obesity are health prob-
lems coexisting with physical impairments
5,45
in a large pro-
portion of young adults with PFP. This finding is consistent
with a previous systematic review of 33 cross-sectional stud-
ies, which reported that young adults with PFP have greater
BMI compared with pain-free controls.
15
Interestingly,
Table 2
Pearson correlation coefficients (r) among BMI, body fat percentage, lean mass percentage, functional capacity, and strength measures.
Variables BMI (kg/m
2
) Body fat percentage Lean mass percentage
AKPS 0.28 (0.005)*0.25 (0.015)*0.22 (0.032)*
Plank
a
0.34 (0.001)*0.37 (<0.001)*0.38 (<0.001)*
Single-leg hop test (cm) 0.41 (<0.001)*0.46 (<0.001)*0.44 (<0.001)*
Peak isometric knee extension 0.17 (0.087) 0.43 (<0.001)*0.57 (<0.001)*
Peak isometric knee flexion 0.22 (0.031)*0.40 (<0.001)*0.56 (<0.001)*
Peak isometric hip abduction 0.07 (0.510) 0.49 (<0.001)*0.57 (<0.001)*
Note: Data were adjusted for sex, presence of bilateral pain, and current pain level (VAS), and presented as r(p).
a
Log transformed.
*p<0.05.
Abbreviations: AKPS = Anterior Knee Pain Scale; BMI = body mass index; VAS = visual analogue scale.
Table 3
Hierarchical linear regression between BMI and functional capacity, and knee flexion strength.
Dependent variable Model Independent variable R
2
ΔR
2
ΔFb(95%CI)
AKPS 1 Covariates
a
0.20
2 BMI 0.26 0.06 8.29** 0.57 (0.96 to 0.17)
Plank
b
1 Covariates
a
0.26
2 BMI 0.35 0.09 12.64** 0.02 (0.03 to 0.01)
Single-leg hop test 1 Covariates
a
0.30
2 BMI 0.42 0.12 18.94** 1.90 (2.76 to 1.03)
Peak isometric knee flexion strength 1 Covariates
a
0.07
2 Body fat 0.11 0.04 4.81*1.53 (0.14 to 2.92)
a
Adjusted for sex, presence of bilateral pain, and current pain level.
b
Log transformed.
*
p<0.05;
**
p<0.01.
Abbreviations: AKPS = Anterior Knee Pain Scale; BMI = body mass index; CI = confidence interval.
Table 4
Hierarchical linear regression between body fat and functional capacity, and strength measures.
Dependent variable Model Independent variable R
2
ΔR
2
ΔFb(95%CI)
AKPS 1 Covariates
a
0.20
2 Body fat 0.25 0.05 6.19*0.33 (0.59 to 0.06)
Plank
b
1 Covariates
a
0.26
2 Body fat 0.36 0.10 15.10** 0.01 (0.02 to 0.01)
Single leg hop test 1 Covariates
a
0.30
2 Body fat 0.45 0.15 25.03** 1.41 (1.97 to 0.85)
Peak isometric knee extension strength 1 Covariates
a
0.05
2 Body fat 0.23 0.18 21.81** 2.60 (3.71 to 1.49)
Peak isometric knee flexion strength 1 Covariates
a
0.07
2 Body fat 0.22 0.15 18.50** 1.26 (1.85 to 0.68)
Peak isometric hip abductor strength 1 Covariates
a
0.04
2 Body fat 0.27 0.23 30.43** 1.12 (1.53 to 0.72)
a
Adjusted for sex, presence of bilateral pain, and current pain level.
b
Log transformed.
*
p<0.05:
**
p<0.01.
Abbreviations: AKPS = Anterior Knee Pain Scale; CI = confidence interval.
ARTICLE IN PRESS
Please cite this article as: Amanda Schenatto Ferreira et al., Overweight and obesity in young adults with patellofemoral pain: Impact on functional capacity and strength, Journal of
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6 A.S. Ferreira et al.

evidence from 2 systematic reviews of prospective studies sug-
gests that BMI might not be a risk factor for PFP.
12,15
This
indicates that overweight may be a consequence of living with
PFP (rather than overweight or obesity predisposing PFP),
with PFP known to lead to reduced physical activity levels and
psychological impairments.
4,10,50
However, many of the stud-
ies included in these systematic reviews
12,15
(six of 12 studies)
investigated BMI as a risk factor for PFP in military popula-
tions. Future prospective studies are needed to confirm if
higher BMI values are a risk factor for (or consequence of)
PFP in other populations such as young adults, adolescents,
and recreational sports population.
Our findings suggest that higher BMI, higher body fat, and
lower lean mass are associated with poor subjective and objec-
tive functional capacity. Previous research in other musculo-
skeletal conditions assessing the relationship of BMI, body fat,
and lean mass with functional capacity has yielded conflicting
findings.
18,19,51
Davis et al.
18
reported an association between
body fat and lean mass and objective functional capacity in
older adults with knee OA. However, BMI was not associated
with either subjective or objective functional capacity. None-
theless, when people with different levels of overweight are
compared, those with higher BMI reported poor subjective
functional capacity in knee OA
19
and chronic low back pain.
51
These findings provide important clinical implications, given
that patients with PFP reporting poor functional capacity are
most likely to have poor long-term outcomes.
13,14
Exercise
therapy targeting the hip and knee is a key recommendation of
international consensus and clinical practice guidelines to
improving pain and function in people with PFP.
35,52,53
How-
ever, a prognostic study indicated that more than half of people
with PFP report unfavorable outcomes 58 years after being
enrolled in exercise-based rehabilitation.
14
This suggests a
need for alternative approaches that are more tailored to
patient needs.
31
Our findings suggest that greater BMI, higher
body fat, and lower lean mass are predictive of poor functional
capacity and reduced knee and hip strength. Therefore,
considering management approaches beyond exercise therapy
that incorporate weight management may be a potential alter-
native to enhance long-term outcomes for patients with PFP.
This approach has been reported to be successful in people
with knee OA, with weight management interventions leading
to improvements in pain, functional capacity, and knee
strength.
2730
According to our findings, BMI was associated with knee
flexion strength but not with knee extension and hip strength.
A potential explanation for this finding is that BMI does not
take into account specific components of body composition
(i.e., body fat and lean mass); consequently, the relative contri-
bution of these components to muscle strength cannot be deter-
mined. Additionally, although we included sex as a covariate
during statistical analysis and did not find a significant differ-
ence between BMI groups for proportion of males and females
(Supplementary Table S1), the inclusion of a non-balanced
mixed-sex sample across BMI categories is a limitation of our
study. A previous systematic review has indicated larger hip
strength deficits for female populations compared to male and
mixed-sex populations, which supports the notion that males
and females present different deficits and may represent dis-
tinct subgroups within PFP.
40
Our novel findings indicate that higher body fat and
lower lean mass are associated with reduced knee and hip
strength. Overweight has been associated with alterations in
skeletal muscle, such as increased lipid accumulation
between (intermuscular fat) and within skeletal muscle
fibers,
54,55
which in turn seems to affect muscular quality
(muscle strength relative to unit of muscle mass) in people
with knee OA.
54,56,57
These physiological changes in the
skeletal muscle as a consequence of overweight may nega-
tively influence knee extensor strength and physical function
in people with knee OA.
56,58
Fat infiltration in muscle fibers
could not be detected by bioelectrical impedance and there-
fore is a limitation of our study. Further research is war-
ranted to explore this hypothesis.
Table 5
Hierarchical linear regression between lean mass and functional capacity, and strength measures.
Dependent variable Model Independent variable R
2
ΔR
2
ΔFb(95%CI)
AKPS 1 Covariates
a
0.20
2 Lean mass 0.24 0.04 4.73*0.58 (0.05 to 1.11)
Plank
b
1 Covariates
a
0.26
2 Lean mass 0.37 0.11 16.24** 0.03 (0.01 to 0.04)
Single-leg hop test (cm) 1 Covariates
a
0.30
2 Lean mass 0.43 0.13 22.14** 2.69 (1.55 to 3.82)
Peak isometric knee extension strength 1 Covariates
a
0.05
2 Lean mass 0.36 0.31 46.43** 5.02 (3.55 to 6.48)
Peak isometric knee flexion strength 1 Covariates
a
0.07
2 Lean mass 0.36 0.29 43.53** 2.55 (1.78 to 3.32)
Peak isometric hip abductor strength 1 Covariates
a
0.04
2 Lean mass 0.35 0.31 45.02** 1.88 (1.32 to 2.44)
a
Adjusted for sex, presence of bilateral pain, and current pain level.
b
Log transformed.
*
p<0.05:
**
p<0.01.
Abbreviations: AKPS = Anterior Knee Pain Scale; CI = confidence interval.
ARTICLE IN PRESS
Please cite this article as: Amanda Schenatto Ferreira et al., Overweight and obesity in young adults with patellofemoral pain: Impact on functional capacity and strength, Journal of
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Overweight in patellofemoral pain 7

4.1. Clinical implications
Our findings suggest that BMI, body fat, and lean mass
should be considered in the assessment and management of
PFP because, depending on their levels, they may be detrimen-
tal to functional capacity and particularly strength. Weight
management interventions (diet only or a combination of diet
plus exercise) have been reported to be effective to improving
pain, functional capacity, and knee strength in people with
knee OA.
2730,59
Considering that 38% of our cohort were
overweight or obese, weight management and advice on a
healthier lifestyle
60
should be considered for young adults
with PFP. Additionally, we found that lean mass was the best
predictor of strength, explaining 31%, 29%, and 31% of the
variance in knee extensor, knee flexor, and hip abductor
strength, respectively, while body fat explained 18%, 15%,
and 23%, respectively. These findings may suggest that devel-
opers of interventions targeting weight loss as a treatment
modality for PFP need to consider the impact of the weight
loss intervention on lean mass specifically. Therefore, inter-
ventions focusing on combined diet and strength training
rather than diet only may be the best option for people with
PFP, particularly for those categorized as obese,
61,62
because
they seem to have the lowest knee and hip strength (Supple-
mentary Table S1). This hypothesis should be a research prior-
ity because there has been no randomized controlled trial in
PFP targeting weight loss.
31
4.2. Limitations
Due to the first aim of the study (to determine the propor-
tion of overweight/obesity in our sample of young adults with
PFP), we did not create equal samples within BMI categories,
which could have influenced our results regarding the second
aim (to examine associations between body composition and
functional capacity and strength). Due to our sample size, we
chose to account for sex as a covariate within the regression
model rather than stratify the cohort into subgroups. Future
studies stratifying the sample based on sex are needed in order
to better understand its contribution in the relationship of
BMI, body fat, and lean mass with functional capacity and
strength in PFP. Although we have attempted to control for
some important covariates in our analyses (sex, bilateral pain,
and current pain level), caution should be taken when inter-
preting our findings because the participants’ physical activity
level was not assessed in our cohort; further inquiry into the
influence of physical activity level is warranted to determine
whether it may serve as a potential covariate for the observed
relationships. Our findings are also limited to individuals
1835 years old. Adolescents and older populations with PFP
may present different distributions of BMI, body fat, and lean
mass,
15,63
and this requires consideration in future research.
Last, we only investigated the impact of BMI, body fat, and
lean mass on functional capacity and strength measures; future
research should explore the impact of overweight and obesity
in psychological, biomechanical, and other clinical outcomes
in people with PFP.
5. Conclusion
Higher BMI, higher body fat, and lower lean mass are asso-
ciated with poor functional capacity in young adults with PFP.
Higher body fat and lean mass, but not BMI, were also associ-
ated with reduced knee and hip strength. These findings indi-
cate that when managing people with PFP, assessment of
BMI, body fat, and lean mass is warranted because it has an
impact on clinical outcomes.
Acknowledgments
Amanda Schenatto Ferreira is supported by a PhD scholar-
ship from Sao Paulo Research Foundation - FAPESP (scholar-
ship No. 2018/17106-0).
Authors’ contributions
ASF and DOS conceived the study’s design and carried out
data collection, data analysis and interpretation, and drafting
of the manuscript; BFM contributed to statistical analysis and
data interpretation and helped revise the manuscript; BT par-
ticipated in the design of the study and contributed to data col-
lection; MFP participated in the design of the study and helped
revise the manuscript; FMA provided a critical review of the
manuscript. All authors have read and approved the final ver-
sion of the manuscript, and agree with the order of presentation
of the authors.
Competing interests
The authors declare that they have no competing interests.
Supplementary materials
Supplementary material associated with this article can be
found, in the online version, at doi:10.1016/j.jshs.2020.12.002.
References
1. Crossley KM, Stefanik JJ, Selfe J, et al. 2016 Patellofemoral pain consen-
sus statement from the 4th International Patellofemoral Pain Research
Retreat, Manchester. Part 1: terminology, definitions, clinical examina-
tion, natural history, patellofemoral osteoarthritis and patient-reported
outcome measures.. Br J Sports Med 2016;50:839–43.
2. Smith BE, Selfe J, Thacker D, et al. Incidence and prevalence of patellofe-
moral pain: a systematic review and meta-analysis. PLoS One 2018;13:
e0190892. doi:10.1371/journal.pone.0190892.
3. Coburn SL, Barton CJ, Filbay SR, Hart HF, Rathleff MS, Crossley KM.
Quality of life in individuals with patellofemoral pain: a systematic
review including meta-analysis. Phys Ther Sport 2018;33:96–108.
4. Priore LB, Azevedo FM, Pazzinatto MF, et al. Influence of kinesiophobia
and pain catastrophism on objective function in women with patellofemoral
pain. Phys Ther Sport 2019;35:116–21.
5. Nunes GS, de Oliveira Silva D, Crossley KM, Serr~
ao FV, Pizzari T, Bar-
ton CJ. People with patellofemoral pain have impaired functional perfor-
mance, that is correlated to hip muscle capacity. Phys Ther Sport
2019;40:85–90.
6. Eijkenboom JFA, Waarsing JH, Oei EHG, Bierma-Zeinstra SMA, van
Middelkoop M. Is patellofemoral pain a precursor to osteoarthritis? Patel-
lofemoral osteoarthritis and patellofemoral pain patients share aberrant
patellar shape compared with healthy controls. Bone Jt Res 2018;7:541–7.
ARTICLE IN PRESS
Please cite this article as: Amanda Schenatto Ferreira et al., Overweight and obesity in young adults with patellofemoral pain: Impact on functional capacity and strength, Journal of
Sport and Health Science (2021), https://doi.org/10.1016/j.jshs.2020.12.002
8 A.S. Ferreira et al.

7. Crossley KM. Is patellofemoral osteoarthritis a common sequela of patel-
lofemoral pain? Br J Sports Med 2014;48:409–10.
8. Wyndow N, Collins N, Vicenzino B, Tucker K, Crossley K. Is there a bio-
mechanical link between patellofemoral pain and osteoarthritis? A narra-
tive review. Sport Med 2016;46:1797–808.
9. Lack S, Neal B, De Oliveira Silva D, Barton C. How to manage patellofe-
moral pain—understanding the multifactorial nature and treatment
options. Phys Ther Sport 2018;32:155–66.
10. Maclachlan LR, Collins NJ, Matthews MLG, Hodges PW, Vicenzino B.
The psychological features of patellofemoral pain: a systematic review.
Br J Sports Med 2017;51:732–42.
11. Powers CM, Witvrouw E, Davis IS, Crossley KM. Evidence-based framework
for a pathomechanical model of patellofemoral pain: 2017 patellofemoral pain
consensus statement from the 4th International Patellofemoral Pain Research
Retreat, Manchester, UK: part 3. Br J Sports Med 2017;51:1713–23.
12. Neal BS, Lack SD, Lankhorst NE, Raye A, Morrissey D, van Middelkoop
M. Risk factors for patellofemoral pain: a systematic review and meta-
analysis. Br J Sports Med 2019;53:270–81.
13. Collins NJ, Bierma-zeinstra SM, Crossley KM, van Linschoten RL, Vice-
nzino B, van Middelkoop M. Prognostic factors for patellofemoral pain: a
multicentre observational analysis. Br J Sports Med 2013;47:227–33.
14. Lankhorst NE, van Middelkoop M, Crossley KM, et al. Factors that predict a
poor outcome 58 years after the diagnosis of patellofemoral pain: a multi-
centre observational analysis. Br J Sports Med 2016;50:881–6.
15. Hart HF, Barton CJ, Khan KM, Riel H, Crossley KM. Is body mass index
associated with patellofemoral pain and patellofemoral osteoarthritis? A
systematic review and meta-regression and analysis. Br J Sports Med
2017;51:781–90.
16. Kastelein M, Luijsterburg PA, Heintjes EM, et al. The 6-year trajectory of
non-traumatic knee symptoms (including patellofemoral pain) in adoles-
cents and young adults in general practice: a study of clinical predictors.
Br J Sports Med 2015;49:400–5.
17. Sowers MF, Yosef M, Jamadar D, Jacobson J, Karvonen-Gutierrez C,
Jaffe M. BMI vs. body composition and radiographically-defined osteoar-
thritis of the knee in women: a 4-year follow-up study. Osteoarthr Cartil
2008;16:367–72.
18. Davis HC, Blue MNM, Hirsch KR, et al. Body composition is associated
with physical performance in individuals with knee osteoarthritis. J Clin
Rheumatol 2020;26:109–14.
19. Raud B, Gay C, Guiguet-auclair C, et al. Level of obesity is directly asso-
ciated with the clinical and functional consequences of knee osteoarthritis.
Sci Rep 2020;10:3601. doi:10.1038/s41598-020-60587-1.
20. Culvenor AG, Felson DT, Niu J, et al. Thigh muscle specific-strength and
the risk of incident knee osteoarthritis: the influence of sex and greater
body mass index. Arthritis Care Res 2017;69:1266–70.
21. Batsis JA, Zbehlik AJ, Barre LK, Bynum JP, Pidgeon D, Bartels SJ.
Impact of obesity on disability, function and physical activity: data from
the Osteoarthritis Initiative. Scand J Rheumatol 2015;44:495–502.
22. Kurt¸ca MP, Aslan UB, Senol H. Is functional level related with body com-
position in patients with knee osteoarthritis. Osteoarthr Cartil 2019;27:
S447. doi:10.1016/j.joca.2019.02.482.
23. Hussain SM, Tan MC, Stathakopoulos K, et al. How are obesity and body
composition related to patellar cartilage? A systematic review. J Rheuma-
tol 2017;44:1071–82.
24. Ding C, Parameswaran V, Cicuttini F, et al. Association between leptin,
body composition, sex and knee cartilage morphology in older adults: the
Tasmanian older adult cohort (TASOAC) study. Ann Rheum Dis
2008;67:1256–61.
25. Sowers M, Karvonen-Gutierrez CA, Jacobson JA, Jiang Y, Yosef M.
Associations of anatomical measures from MRI with radiographically
defined knee osteoarthritis score, pain, and physical functioning. J Bone
Joint Surg Am 2011;93:241–51.
26. Kim N, Browning RC, Lerner ZF. The effects of pediatric obesity on
patellofemoral joint contact force during walking. Gait Posture 2019;
73:209–14.
27. Riddle DL, Stratford PW. Body weight changes and corresponding
changes in pain and function in persons with symptomatic knee osteoar-
thritis: a cohort study. Arthritis Care Res (Hoboken) 2013;65:15–22.
28. Messier SP, Resnik AE, Beavers DP, et al. Intentional weight loss for
overweight and obese knee osteoarthritis patients: is more better.
Arthritis Care Res (Hoboken) 2018;70:1569–75.
29. Atukorala I, Makovey J, Lawler L, Messier SP, Bennell K, Hunter DJ. Is
there a dose-response relationship between weight loss and symptom
improvement in persons with knee osteoarthritis? Arthritis Care Res
(Hoboken) 2016;68:1106–14.
30. Henriksen M, Christensen R, Danneskiold-samsøe B, Bliddal H. Changes
in lower extremity muscle mass and muscle strength after weight loss in
obese patients with knee osteoarthritis: a prospective cohort study. Arthri-
tis Rheum 2012;64:438–42.
31. Barton CJ, Crossley KM, Macri EM. Should we consider changing tradi-
tional physiotherapy treatment of patellofemoral pain based on recent
insights from the literature? Br J Sports Med 2018;52:1546–7.
32. Urquhart DM, Berry P, Wluka AE, et al. Increased fat mass is associated
with high levels of low back pain intensity and disability. Spine (Phila Pa
1976) 2011;36:1320–5.
33. Hussain SM, Urquhart DM, Wang Y, et al. Fat mass and fat distribution
are associated with low back pain intensity and disability: results from a
cohort study. Arthritis Res Ther 2017;19:26. doi:10.1186/s13075-017-
1242-z.
34. Yoo JJ, Cho NH, Lim SH, Kim HA. Relationships between body mass
index, fat mass, muscle mass, and musculoskeletal pain in community res-
idents. Arthritis Rheumatol 2014;66:3511–20.
35. Collins NJ, Barton CJ, van Middelkoop M, et al. 2018 Consensus state-
ment on exercise therapy and physical interventions (orthoses, taping and
manual therapy) to treat patellofemoral pain: recommendations from the
5th International Patellofemoral Pain Research Retreat, Gold Coast, Aus-
tralia, 2017. Br J Sports Med 2018;52:1170–8.
36. von Elm E, Altman DG, Egger M, et al. Strengthening the Reporting of
Observational Studies in Epidemiology (STROBE) statement: guidelines
for reporting observational studies. Br Med J 2007;335:806–8.
37. Crossley KM, Bennell KL, Cowan SM, Green S. Analysis of outcome
measures for persons with patellofemoral pain: which are reliable and
valid? Arch Phys Med Rehabil 2004;85:815–22.
38. Karachalios T, Hantes M, Zibis AH, Zachos V, Karantanas AH, Mali-
zos KN. Diagnostic accuracy of a new clinical test (the Thessaly test)
for early detection of meniscal tears. J Bone Joint Surg Am 2005;87:
955–62.
39. Benjaminse A, Gokeler A, van der Schans CP. Clinical diagnosis of an
anterior cruciate ligament rupture: a meta-analysis. J Orthop Sport Phys
Ther 2005;36:267–88.
40. Rathleff MS, Rathleff CR, Crossley KM, Barton CJ. Is hip strength a risk
factor for patellofemoral pain? A systematic review and meta-analysis. Br
J Sports Med 2014;48:1088. doi:10.1136/bjsports-2013-093305.
41. Boling MC, Nguyen AD, Padua DA, Cameron KL, Beutler A, Marshall
SW. Gender-specific risk factor profiles for patellofemoral pain. Clin J Sport
Med. 2019. doi:10.1097/JSM.0000000000000719. [Epub ahead of print].
42. Pazzinatto MF, de Oliveira Silva D, Barton C, Rathleff MS, Briani RV, de
Azevedo FM. Female adults with patellofemoral pain are characterized by
widespread hyperalgesia, which is not affected immediately by patellofe-
moral joint loading. Pain Med 2016;17:1953–61.
43. Vasold KL, Parks AC, Phelan DML, Pontifex MB, Pivarnik JM. Reliabil-
ity and validity of commercially available low-cost bioelectric impedance
analysis. Int J Sport Nutr Exerc Metab 2019;29:406–10.
44. Durall CJ, Greene PF, Kernozek TW. A comparison of two isometric tests
of trunk flexor endurance. J Strength Cond Res 2012;26:1939–44.
45. Ferreira AS, de Oliveira Silva D, Barton CJ, et al. Impaired isometric,
concentric, and eccentric rate of torque development at the hip and knee
in patellofemoral pain. J Strength Cond Res. 2019. doi:10.1519/
jsc.0000000000003179. [Epub ahead of print].
46. Nunes GS, de Oliveira Silva D, Pizzari T, Serr~
ao FV, Crossley KM, Bar-
ton CJ. Clinically measured hip muscle capacity deficits in people with
patellofemoral pain. Phys Ther Sport 2019;35:69–74.
47. Obesity WHO. preventing and managing the global epidemic. Report of a
WHO consultation. World Health Organ Tech Rep Ser 2000;894:1–253.
48. Field A. Discovering Statistics Using SPSS. 3rd ed. London: SAGE Publi-
cations Ltd; 2009.
ARTICLE IN PRESS
Please cite this article as: Amanda Schenatto Ferreira et al., Overweight and obesity in young adults with patellofemoral pain: Impact on functional capacity and strength, Journal of
Sport and Health Science (2021), https://doi.org/10.1016/j.jshs.2020.12.002
Overweight in patellofemoral pain 9

49. Cohen J. Statistical Power Analysis for the Behavioral Sciences. 2nd ed.
New York, NY: Routledge Academic; 1988.
50. Glaviano NR, Baellow A, Saliba S. Physical activity levels in individuals
with and without patellofemoral pain. Phys Ther Sport 2017;27:12–6.
51. Wertli MM, Held U, Campello M, Schecter Weiner S. Obesity is associ-
ated with more disability at presentation and after treatment in low back
pain but not in neck pain: findings from the OIOC registry. BMC Muscu-
loskelet Disord 2016;17:140. doi:10.1186/s12891-016-0992-0.
52. Willy RW, Hoglund LT, Barton CJ, et al. Patellofemoral pain: clinical
practice guidelines linked to the international classification of functioning,
disability and health from the academy of orthopaedic physical therapy of
the American Physical Therapy Association. J Orthop Sport Phys Ther
2019;49. CPG157.
53. Barton CJ, Lack S, Hemmings S, Tufail S, Morrissey D. The “Best
Practice Guide to Conservative Management of Patellofemoral Pain”:
incorporating level 1 evidence with expert clinical reasoning. Br J Sports
Med 2015;49:923–34.
54. Bollinger LM. Potential contributions of skeletal muscle contractile dys-
function to altered biomechanics in obesity. Gait Posture 2017;56:100–7.
55. Pedroso MG, de Almeida AC, Aily JB, de Noronha M, Mattiello SM.
Fatty infiltration in the thigh muscles in knee osteoarthritis: a systematic
review and meta-analysis. Rheumatol Int 2019;39:627–35.
56. Kumar D, Karampino DC, MacLeod TD, et al. Quadriceps intramuscular
fat fraction rather than muscle size is associated with knee osteoarthritis.
Osteoarthr Cartil 2014;22:226–34.
57. Conroy MB, Kwoh CK, Krishnan E, et al. Muscle strength, mass, and
quality in older men and women with knee osteoarthritis. Arthritis Care
Res (Hoboken) 2012;64:15–21.
58. Maly MR, Calder KM, Macintyre NJ, Beattie KA. Relationship of inter-
muscular fat volume in the thigh relates to knee extensor strength and
physical performance in women at risk for or with knee osteoarthritis.
Arthritis Care Res (Hoboken) 2013;65:44–52.
59. Messier SP, Mihalko SL, Legault C, et al. Effects of intensive diet and
exercise on knee joint loads, inflammation, and clinical outcomes among
overweight and obese adults with knee osteoarthritis: the IDEA random-
ized clinical trial. JAMA 2013;310:1263–73.
60. de Oliveira Silva D, Pazzinatto MF, Rathleff MS, et al. Patient education
for patellofemoral pain: a systematic review. J Orthop Sport Phys Ther
2020;50:388–96.
61. Hulens M, Vansant G, Lysens R, Claessens AL, Muls E. Assessment of
isokinetic muscle strength in women who are obese. J Orthop Sport Phys
Ther 2002;32:347–56.
62. Hulens M, Vansant G, Lysens R, Claessens AL, Muls E, Brumagne S.
Study of differences in peripheral muscle strength of lean versus obese
women: an allometric approach. Int J Obes Relat Metab Disord
2001;25:676–81.
63. Barber Foss KD, Hornsby M, Edwards NM, Myer GD, Hewett TE. Is
body composition associated with an increased risk of developing
anterior knee pain in adolescent female athletes. Phys Sportsmed
2012;40:13–9.
ARTICLE IN PRESS
Please cite this article as: Amanda Schenatto Ferreira et al., Overweight and obesity in young adults with patellofemoral pain: Impact on functional capacity and strength, Journal of
Sport and Health Science (2021), https://doi.org/10.1016/j.jshs.2020.12.002
10 A.S. Ferreira et al.