Boxing Training for Patients With Parkinson Disease: A Case Series

Abstract

A nontraditional form of exercise recently applied for patients with Parkinson disease (PD) is boxing training. The primary purpose of this case series is to describe the effects of disease severity and duration of boxing training (short term and long term) on changes in balance, mobility, and quality of life for patients with mild or moderate to severe PD. The feasibility and safety of the boxing training program also were assessed.
Six patients with idiopathic PD attended 24 to 36 boxing training sessions for 12 weeks, with the option of continuing the training for an additional 24 weeks (a seventh patient attended sessions for only 4 weeks). The 90-minute sessions included boxing drills and traditional stretching, strengthening, and endurance exercises. Outcomes were tested at the baseline and after 12, 24, and 36 weeks of boxing sessions (12-, 24-, and 36-week tests). The outcome measures were the Functional Reach Test, Berg Balance Scale, Activities-specific Balance Confidence Scale, Timed "Up & Go" Test, Six-Minute Walk Test, gait speed, cadence, stride length, step width, activities of daily living and motor examination subscales of the Unified Parkinson Disease Rating Scale, and Parkinson Disease Quality of Life Scale.
Six patients completed all phases of the case series, showed improvements on at least 5 of the 12 outcome measures over the baseline at the 12-week test, and showed continued improvements at the 24- and 36-week tests. Patients with mild PD typically showed improvements earlier than those with moderate to severe PD.
Despite the progressive nature of PD, the patients in this case series showed short-term and long-term improvements in balance, gait, activities of daily living, and quality of life after the boxing training program. A longer duration of training was necessary for patients with moderate to severe PD to show maximal training outcomes. The boxing training program was feasible and safe for these patients with PD.

Full text

doi: 10.2522/ptj.20100142
Originally published online November 18, 2010
2011; 91:132-142.PHYS THER.
Schaneman
Lindsay Conn, Kendra Davis, Nicole Lewis and Katie
Stephanie A. Combs, M. Dyer Diehl, William H. Staples,
A Case Series
Boxing Training for Patients With Parkinson Disease:
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Boxing Training for Patients With
Parkinson Disease: A Case Series
Stephanie A. Combs, M. Dyer Diehl, William H. Staples, Lindsay Conn,
Kendra Davis, Nicole Lewis, Katie Schaneman
Background and Purpose. A nontraditional form of exercise recently applied
for patients with Parkinson disease (PD) is boxing training. The primary purpose of
this case series is to describe the effects of disease severity and duration of boxing
training (short term and long term) on changes in balance, mobility, and quality of life
for patients with mild or moderate to severe PD. The feasibility and safety of the
boxing training program also were assessed.
Case Descriptions. Six patients with idiopathic PD attended 24 to 36 boxing
training sessions for 12 weeks, with the option of continuing the training for an
additional 24 weeks (a seventh patient attended sessions for only 4 weeks). The
90-minute sessions included boxing drills and traditional stretching, strengthening,
and endurance exercises. Outcomes were tested at the baseline and after 12, 24, and
36 weeks of boxing sessions (12-, 24-, and 36-week tests). The outcome measures
were the Functional Reach Test, Berg Balance Scale, Activities-specific Balance Con-
fidence Scale, Timed “Up & Go” Test, Six-Minute Walk Test, gait speed, cadence,
stride length, step width, activities of daily living and motor examination subscales of
the Unified Parkinson Disease Rating Scale, and Parkinson Disease Quality of Life
Scale.
Outcomes. Six patients completed all phases of the case series, showed improve-
ments on at least 5 of the 12 outcome measures over the baseline at the 12-week test,
and showed continued improvements at the 24- and 36-week tests. Patients with mild
PD typically showed improvements earlier than those with moderate to severe PD.
Discussion. Despite the progressive nature of PD, the patients in this case series
showed short-term and long-term improvements in balance, gait, activities of daily
living, and quality of life after the boxing training program. A longer duration of
training was necessary for patients with moderate to severe PD to show maximal
training outcomes. The boxing training program was feasible and safe for these
patients with PD.
S.A. Combs, PT, PhD, NCS, is As-
sistant Professor, Krannert School
of Physical Therapy, University of
Indianapolis, 1400 E Hanna Ave,
Indianapolis, IN 46227 (USA). Ad-
dress all correspondence to Dr
Combs at: scombs@uindy.edu.
M.D. Diehl, PT, PhD, is Assistant
Professor, Krannert School of
Physical Therapy, University of
Indianapolis.
W.H. Staples, PT, DPT, DHS, GCS,
is Assistant Professor, Krannert
School of Physical Therapy, Uni-
versity of Indianapolis.
L. Conn, PT, DPT, is Staff Physical
Therapist, St Francis Hospital, In-
dianapolis, Indiana. She was a DPT
student in the Krannert School of
Physical Therapy, University of In-
dianapolis, at the time the study
was conducted.
K. Davis, PT, DPT, is Staff Physical
Therapist, Accord Children’s Ther-
apy, Franklin, Indiana. She was a
DPT student in the Krannert School
of Physical Therapy, University of In-
dianapolis, at the time the study
was conducted.
N. Lewis, PT, DPT, is Staff Physical
Therapist, Possibilities Northeast,
Fort Wayne, Indiana. She was a
DPT student in the Krannert
School of Physical Therapy, Uni-
versity of Indianapolis, at the time
the study was conducted.
K. Schaneman, PT, DPT, is Staff
Physical Therapist, Good Samari-
tan Hospital, Kearney, Nebraska.
She was a DPT student in the
Krannert School of Physical Ther-
apy, University of Indianapolis, at
the time the study was conducted.
[Combs SA, Diehl MD, Staples
WH, et al. Boxing training for pa-
tients with Parkinson disease: a
case series. Phys Ther. 2011;91:
132–142.]
© 2011 American Physical Therapy
Association
Case Report
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Parkinson disease (PD) is a pro-
gressive neurodegenerative dis-
order that is characterized by
tremors, postural rigidity, bradykine-
sia, and postural instability.
1
These
motor signs can have detrimental ef-
fects on balance, mobility, and qual-
ity of life in patients with PD.
1
In-
creasing evidence has indicated that
traditional forms of exercise, such as
stretching and aerobic and resis-
tance training, provide positive
health benefits and improved quality
of life for patients with PD.
2–7
Alter-
native, nontraditional group exercise
programs implemented within com-
munity settings have also shown
promise.
8–11
Nontraditional exercise
programs integrate traditional exer-
cise concepts but apply them in an
alternative manner. Examples in-
clude tango dance,
8
tai chi,
11
taiji,
9
and qigong.
10
These programs have
been found to increase balance,
8,11
mobility,
8,11,12
and gait endurance,
11
as well as to improve perceived
physical, psychological, and social
abilities.
9
A nontraditional form of exercise re-
cently applied for patients with PD is
boxing training. Customary boxing
training is designed so that boxers
have sufficient endurance to last the
duration of each round with enough
explosive strength to throw punches
and move quickly within the boxing
ring.
13
In combination with fitness
activities, boxing training incorpo-
rates whole-body movements, with
upper-extremity punching motions
and lower-extremity footwork in
multiple directions. The punching
actions combine high-speed arm mo-
tions with trunk rotation and antici-
patory postural adjustments.
14
The
actions used in boxing training incor-
porate motions similar to those de-
scribed in previous reports, such as
spinal flexibility,
15
stepping in multi-
ple directions,
16
and movements
performed faster than preferred
speeds.
3,16,17
Therefore, boxing
training may be an effective alterna-
tive for improving function in pa-
tients with PD.
We found only 2 studies that inves-
tigated the effects of boxing training
in young adults who were
healthy.
18,19
Kravitz et al
18
reported
that upper-extremity boxing mo-
tions at any speed provided adequate
exercise intensity to improve cardio-
respiratory fitness. Bellinger et al
19
found that a 60-minute boxing train-
ing session resulted in an energy ex-
penditure similar to that resulting
from running about 9 km (5.6 miles)
in 60 minutes on a treadmill. Cur-
rently, there is no evidence on the
effects of boxing training in patients
with PD; however, the use of boxing
training as a component of an exer-
cise program to improve agility and
reduce bradykinesia in patients with
PD has been suggested.
14
In Indianapolis, Indiana, a community-
based group boxing training pro-
gram developed by the Rock Steady
Boxing Foundation has gained re-
markable popularity since its incep-
tion in 2006 by enrolling more than
80 members with mild to severe PD.
Members anecdotally have reported
increased ease in completing activi-
ties of daily living (ADL), decreased
parkinsonian symptoms, and im-
proved perception of quality of life
after participation in the boxing
training program. Therefore, the pri-
mary purpose of this case series is to
describe the effects of disease sever-
ity and duration of boxing training
(short term and long term) on
changes in balance, gait, mobility,
disability, and quality of life for pa-
tients with mild or moderate to se-
vere PD. Because of the novelty of
the intervention for patients with
PD, the feasibility and safety of the
group boxing training program also
were assessed.
Case Descriptions
The case series included patients
who inquired about the boxing train-
ing program developed by the Rock
Steady Boxing Foundation. Patients
had to have a diagnosis of PD; be at
least 21 years of age; currently not be
receiving physical therapy; be able
to ambulate independently in the
home, with or without an assistive
device; be able to follow at least
3-step verbal commands; and be
available for the entire course of the
case series with self-transportation.
Patients could not have preexisting
neurological conditions other than
PD, current musculoskeletal or car-
diovascular conditions that would
limit participation in an exercise pro-
gram, past brain surgery or implan-
tation of a deep brain stimulator, or
current pregnancy.
Seven patients who were new to
boxing training and the Rock Steady
Boxing Foundation program pro-
vided informed consent before be-
ginning the program. During an ini-
tial interview, physical therapists
(S.A.C., M.D.D., and W.H.S.) col-
lected general demographic informa-
tion and administered the Hoehn-
Yahr scale to categorize PD-related
motor dysfunction (moderate to se-
vere impairment⫽score of 3 or 4;
mild impairment⫽scores of 0 –2).
20
Procedures
Testing took place 1 week before the
beginning of the boxing training pro-
gram (baseline) and 1 week after the
completion of 12 weeks (12-week
test) of the boxing training program.
Available With
This Article at
ptjournal.apta.org
•Video: Overview of the Rock
Steady Boxing Training Program
•Audio Abstracts Podcast
This article was published ahead of
print on November 18, 2010, at
ptjournal.apta.org.
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Patients underwent further testing at
24 weeks (24-week test) and 36
weeks (36-week test) regardless of
whether they continued attending
the boxing training program. Physi-
cal therapists and physical therapist
students (L.C., K.D., N.L., and K.S.)
were extensively trained to conduct
all outcome measures. Intrarater re-
liability and interrater reliability
were established with the Berg Bal-
ance Scale (BBS) (intraclass correla-
tion coefficient [ICC]⫽.998). Tests
were randomized in each testing ses-
sion to reduce the effects of test or-
der bias. For patients taking medica-
tions for PD, testing was conducted
approximately 1 hour after the med-
ications were taken.
Outcome Measures
Balance
Because boxing training incorpo-
rates weight shifting from the base of
support, dynamic changes in bal-
ance, and postural adjustments, we
chose the following outcome mea-
sures: Functional Reach Test (FRT),
BBS, and Activities-specific Balance
Confidence Scale (ABC).
Margins of stability were assessed
with the FRT.
21
The test-retest reli-
ability of the FRT has been estab-
lished (ICC⫽.73), as has a minimal
detectable change (MDC) of 9 cm for
patients with PD.
22
For the FRT, pa-
tients were instructed to stand with
their arms raised to shoulder height
and reach as far forward as possible
along a meter stick without losing
their balance. The average distance
from 3 trials was used, with greater
reaching distances indicating better
performance.
The BBS was designed to measure
changes in functional standing bal-
ance over time.
23
The summed total
of the 14-item scale ranges from 0 to
56, with higher scores indicating im-
proved balance. The test-retest reli-
ability of the BBS is high (ICC⫽.94),
and an MDC of 5 points has been
established for patients with PD.
22
The ABC was designed to measure
balance confidence in various every-
day activities. The mean score on the
16-item questionnaire ranges from
0% to 100%.
24
The test-retest reliabil-
ity of the ABC is high (ICC⫽.94.),
and an MDC of 13% has been deter-
mined for patients with PD.
22
Gait and Mobility
Because boxing training includes el-
ements of stepping in multiple direc-
tions, changes in speed, fast mo-
tions, and cardiovascular demands,
we chose the following outcome
measures: Timed “Up & Go” Test
(TUG), Six-Minute Walk Test
(6MWT), and spatiotemporal param-
eters of gait.
Mobility was assessed with the
TUG.
25
The test-retest reliability of
the TUG for patients with PD
has been reported to be high
(ICC⫽.85),
22
and the interrater reli-
ability is high (ICC⫽.99) when the
TUG is used during the “on phase” of
the medication cycle.
25
Because the
MDC of 11 seconds established pre-
viously for the TUG was not realistic
or achievable for the patients in the
present case series,
22
the MDC (0.67
second) for the group was calculated
from 3 baseline values. Patients were
instructed to stand up, walk 3 m,
turn around a cone, and return to a
sitting position, beginning with the
instruction “Go.” The average time
from 3 trials was used.
Walking endurance was assessed
with the 6MWT.
22
The test-retest re-
liability of the 6MWT is high
(ICC⫽.96), and the MDC for patients
with PD is 82 m.
22
The 6MWT was
conducted along a 60-m course in a
hallway, with feedback given once
per minute.
Spatiotemporal parameters (speed,
cadence, stride length, and step
width) were assessed with a GaitRite
Walkway System.* Patients were in-
structed to walk at a comfortable
pace on the 4.88-m walkway. The
average value from 5 measurement
trials was used. Patients started and
ended the trials 1.5 m (5 ft) beyond
the GaitRite walkway to ensure a
steady ambulation state. Patients did
not wear orthoses or use assistive
devices during the walking trials. A
physical therapist or a physical ther-
apist student walked beside patients
for safety, if necessary, but no phys-
ical assistance was provided. The
test-retest reliability has been estab-
lished to be high for gait speed
(ICC⫽.93), cadence (ICC⫽.92), and
stride length (ICC⫽.97) measured at
preferred walking paces in adults
who are healthy.
26
An MDC of 0.18
m/s has been established for gait ve-
locity in patients with PD.
22
An MDC
has not been reported for other spa-
tiotemporal parameters in patients
with PD.
PD-Specific Disability and
Quality of Life
Because the boxing training program
was applied specifically for patients
with PD, we chose the following
disease-specific outcome measures:
Unified Parkinson Disease Rating
Scale (UPDRS) and Parkinson Dis-
ease Quality of Life Scale (PDQL).
The UPDRS was designed to monitor
PD-related impairments and disabili-
ties.
27
Activities of daily living sub-
scale II and motor examination sub-
scale III were included in this case
series. The ADL subscale measures
patients’ reported ability to perform
everyday tasks, and the motor exam-
ination subscale measures muscular
involvement of PD, indicating the
severity of motor disease. Lower
scores on the UPDRS signify higher
levels of function. High test-retest re-
liability of the UPDRS (ICC⫽.89 for
the ADL subscale; ICC⫽.93 for the
* CIR Systems Inc, 60 Garlor Dr, Havertown,
PA 19083.
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motor examination subscale) in adults
with PD has been established.
22
Min-
imal detectable changes of 4 points
on the ADL subscale and 11 points
on the motor examination subscale
have been established.
22
The PDQL is a self-administered
quality-of-life questionnaire that con-
tains 37 items.
28
The PDQL total
score has been found to be reliable
(ICC⫽.94) for measuring the quality
of life of patients with PD.
29
A higher
total score on the PDQL indicates a
higher perceived quality of life. An
MDC has not been established for
the PDQL.
Feasibility and Safety
Because boxing training is a rela-
tively new exercise concept for pa-
tients with PD, feasibility and safety
were assessed. Feasibility was deter-
mined on the basis of adherence to
the initial 12-week training protocol
(attending at least 24 sessions). In
addition, adherence to the training
protocol over time was measured as
the number of sessions attended af-
ter the initial 12 weeks. Patient re-
ports regarding enjoyment of the
program were requested. Safety was
evaluated on the basis of the inci-
dence of adverse events.
Intervention
Immediately after baseline testing,
patients completed 24 to 36 boxing
training sessions at the Rock Steady
Boxing Foundation during a 12-week
period. Continuation of boxing train-
ing after the initial 12 weeks was
optional. Patients were instructed to
continue their regular exercise rou-
tines and not to alter routines during
the course of the case series.
The boxing training program began
with a 20-minute warm-up of breath-
ing and stretching exercises for ma-
jor muscle groups in the trunk and
extremities. The warm-up was fol-
lowed by a 45- to 60-minute circuit
training regimen of function, endur-
ance, and punching activities that al-
ternated between 3-minute training
bouts and 1-minute rest breaks. The
functional training incorporated ac-
tivities for whole-body fitness and
calisthenics, such as push-ups, skip-
ping, and jumping rope, along with
boxing ring work, which focused on
footwork and agility drills. The en-
durance training activities included
walking on treadmills, cycling on sta-
tionary bikes, and running outdoors.
The punching activities included
punching heavy bags (heavily pad-
ded, cylindrical bags suspended
from the ceiling for the practice of
large punches), speed bags (small,
air-filled bags suspended from an
overhead platform for the practice of
rhythmic, rapid punches), and focus
mitts (padded mitts worn by a trainer
to prompt the practice of various
combinations of punches toward
moving targets). The activities were
advanced by encouraging patients to
train as intensely as they could toler-
ate by striving to complete more rep-
etitions during each training bout.
The session ended with a 15- to 20-
minute cool-down that emphasized
core stretching and strengthening
and breathing exercises (see video at
ptjournal.apta.org).
The format of the training program
remained constant throughout the
case series, but exercises were var-
ied across sessions. Each training ses-
sion lasted approximately 90 min-
utes and was led by 1 or 2
professional boxers who were certi-
fied as personal trainers by the Na-
tional Academy of Sports Medicine.
Patients wore boxing gloves and per-
formed many activities within a box-
ing ring during the workouts. Pa-
tients did not make contact with
other patients while boxing. Patients
could pace themselves during the
training sessions, taking longer rest
breaks as needed. The case series
physical therapists and physical ther-
apist students were not involved in
the design or implementation of the
boxing training program.
Outcomes
Six patients attended 24 to 36 box-
ing sessions during the initial 12
weeks and completed all 4 measure-
ment sessions. One patient stopped
attending the exercise program after
4 weeks because of a change in
health status that was unrelated to
the case series; therefore, data for
this patient were not included in the
outcomes. Of the 6 patients who
completed all phases of the case se-
ries, 3 patients scored 1 on the
Hoehn-Yahr scale at the baseline, in-
dicating mild motor dysfunction, and
3 patients scored 3 or 4 on the
Hoehn-Yahr scale, indicating moder-
ate to severe motor dysfunction.
20
The demographic characteristics of
the patients are shown in Table 1.
Balance
All patients increased the distance
reached on the FRT by the 24-week
test (Tabs. 2 and 3). As shown in
Figure 1A, patients with moderate to
severe PD consistently increased
their reaching distances during the
course of the case series, with pa-
tients 3 and 4 exceeding the MDC of
9cm
22
at the 36-week test. Patients
with mild PD showed small increases
in their reaching distances over time,
with only patient 1 exceeding the
MDC at the 12-week test.
All patients maintained or increased
their scores on the BBS at the 12- and
24-week tests, and 5 of 6 patients
maintained or further increased their
scores at the 36-week test (Tabs. 2
and 3). Patients 1 and 6 attained the
highest scores possible at the base-
line and maintained these scores at
all subsequent tests. As shown in Fig-
ure 1B, patients with moderate to
severe PD showed consistent im-
provements in their BBS scores dur-
ing the course of the case series,
whereas patients with mild PD
showed little change over time. Two
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patients with moderate to severe PD
(Hoehn-Yahr stage 3 or 4) reached
the MDC of 5 points on the BBS by
the 36-week test.
22
Five of 6 patients maintained or in-
creased their scores on the ABC at
the 24- and 36-week tests (Tabs. 2
and 3). Patients with moderate to
severe PD showed consistent im-
provements in their ABC scores dur-
ing the course of the case series
(Fig. 1C). Patient 5 in that group ex-
ceeded the MDC of 13% at the 24-
week test.
22
Both patients 3 and 5
exceeded the MDC by the 36-week
test. Patients with mild PD showed
little change in balance confidence
over time (Fig. 1C).
Gait and Mobility
Five of 6 patients decreased the time
to complete the TUG at the 12- and
24-week tests, and all patients de-
creased the time by the 36-week test
(Tabs. 2 and 3). All patients ex-
ceeded the MDC during at least 1
measurement session, with 5 of 6
patients exceeding it during the 36-
week test. All patients with mild PD
showed decreases in the time to
complete the TUG of greater than
10% over the baseline immediately
after the initial 12 weeks of boxing
training (Fig. 2A). This change was
not consistently shown by all pa-
tients with moderate to severe PD
until the 24-week test.
Five of 6 patients increased the dis-
tance walked on the 6MWT at the
12- and 24-week tests (Tabs. 2 and
3). All 6 patients increased the dis-
tance walked on the 6MWT at the
36-week test, with 5 of 6 exceeding
the MDC of 82 m.
22
Both patients
with mild PD and patients with mod-
erate to severe PD showed improve-
ments over time, but those with mild
PD showed increases in the distance
walked on the 6MWT of greater than
17% over the baseline by the 24-
week test. This change was not
shown by patients with moderate to
severe PD until the 36-week test
(Fig. 2B).
All 6 patients increased gait speed by
the 24-week test and maintained the
increase over the baseline at the 36-
week test (Tabs. 2 and 3). Patients
with mild PD achieved a 23% in-
crease in gait speed over the baseline
at the 12-, 24-, and 36-week tests,
even with only 1 patient (patient 6)
exceeding the MDC at the 12- and
24-week tests (Fig. 2C).
22
Although
patients with moderate to severe PD
achieved increases in gait speed at
the 24- and 36-week tests, these
changes constituted only 9% and
10% increases over the baseline, re-
spectively. Accordingly, increased
cadence and stride length and de-
creased step width were achieved by
patients with mild PD at the 12-, 24-,
and 36-week tests. However, these
changes in gait parameters were not
achieved by patients with moderate
to severe PD until the 24- and 36-
week tests. Similar to the results for
gait speed, the percent changes
shown by patients with moderate to
severe PD were smaller than those
shown by patients with mild PD.
PD-Specific Disability and
Quality of Life
Both patients with mild PD and pa-
tients with moderate to severe PD
showed consistent decreases in
scores on the ADL subscale of the
UPDRS over time (Fig. 3A). Patients
1, 3, and 4 achieved an MDC of
greater than 4 points on the ADL
subscale of the UPDRS at the 12-
week test, with patients 1 and 4
maintaining the MDC at the 36-week
test (Tabs. 2 and 3).
22
On the motor
examination subscale of the UPDRS,
scores fluctuated (Fig. 3B); only 2
patients with moderate to severe PD
(Hoehn-Yahr stage 3 or 4) achieved
the MDC of 11 points by the 36-week
test.
22
Five of 6 patients had increased total
scores on the PDQL at the 12-, 24-,
and 36-week tests, indicating a
higher self-perceived quality of life
(Tabs. 2 and 3). Both patients with
mild PD and patients with moderate
to severe PD showed consistent im-
provements during the course of the
case series; however, patients with
Table 1.
Demographic Characteristics of Patients With Parkinson Disease (PD)
a
Patient Age (y)
Time Since
Diagnosis
(mo)
Hoehn-Yahr
Stage
Dopamine
Replacement
Medication
PD
Subtype
36
No. of Training Sessions Attended
During Weeks:
1–12 12–24 24–36
1 51 23 1 Yes PIGD 28 19 19
2 55 11 1 No Tremor 24 19 22
3 58 40 3 Yes Tremor 24 11 10
4 77 73 3 Yes ND 30 16 16
5 68 12 4 Yes ND 36 22 30
6 52 13 1 No Tremor 35 3 0
X(SD) 60.17 (10.26) 28.67 (24.34) 2.17 (1.33) 29.5 (5.21) 15 (6.96) 16.17 (10.32)
a
All patients were men. PIGD⫽postural instability gait dominant, ND⫽not differentiated.
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Table 2.
Individual Outcomes for Patients With Mild Parkinson Disease (Hoehn-Yahr Stage 1)
Measurea
Patient 1 Patient 2 Patient 6
Baseline
12-Week
Test
24-Week
Test
36-Week
Test Baseline
12-Week
Test
24-Week
Test
36-Week
Test Baseline
12-Week
Test
24-Week
Test
36-Week
Test
FRT (cm)b30.5 (1.8) 41.1c(1.6) 42.3c(0.3) 30.5 (1.3) 36.4 (1.5) 38.1 (3.5) 39.0 (0.7) 39.0 (1.2) 42.8 (1.0) 34.7 (0.3) 40.6 (0.5) 44.9 (0.7)
BBSd56 56 56 56 55 56 56 56 56 56 56 56
ABCb100.0 (0.0) 100.0 (0.0) 100.0 (0.0) 100.0 (0.0) 91.9 (10.5) 82.5 (22.9) 95.6 (8.1) 93.8 (7.2) 95.6 (7.3) 97.5 (12.4) 85.6 (15.0) 85.6 (7.3)
TUG (s)b9.89 (0.17) 7.87c(0.04) 7.38c(0.13) 8.06c(0.56) 6.58 (0.34) 5.93 (0.78) 4.99c(0.54) 4.91c(0.22) 6.53 (0.38) 5.50c(0.67) 6.03 (0.32) 5.10c(0.17)
6MWTd395.5 510.0c475.8 480.0c584.0 646.8 695.2c628.0 532.9 391.5 602.0 720.0c
Gait speed
(m/s)b0.98 (0.02) 1.10 (0.05) 1.08 (0.04) 1.03 (0.05) 1.14 (0.06) 1.61c(0.07) 1.56c(0.08) 1.69c(0.09) 1.20 (0.02) 1.41c(0.03) 1.42c(0.04) 1.36 (0.05)
Cadence
(steps/
min)b
88.1 (0.7) 93.3 (2.9) 97.0 (2.3) 92.6 (3.3) 105.6 (2.0) 118.1 (3.4) 114.9 (3.7) 118.7 (2.3) 96.2 (1.0) 102.5 (1.2) 105.4 (2.1) 101.1 (2.1)
Stride length
(cm)b113.8 (1.9) 141.2 (3.1) 133.6 (2.9) 133.9 (2.5) 130.3 (4.1) 163.5 (3.0) 163.1 (2.9) 171.4 (6.0) 150.0 (1.7) 165.3 (1.9) 166.8 (1.8) 161.7 (2.7)
Step width
(cm)b12.7 (1.0) 11.5 (0.3) 12.9 (1.3) 12.3 (1.1) 8.5 (0.6) 6.6 (1.7) 6.9 (1.7) 6.8 (2.0) 10.2 (0.2) 9.1 (1.0) 9.3 (1.6) 10.6 (1.1)
UPDRS ADL
subscaled13 4c5c3c7 6 4 4 16 19 18 13
UPDRS
motor
subscaled
0 2 10 8 13 16 15 10 16 26 6 9
PDQLd142 174 170 177 139 143 140 145 115 100 104 114
a
FRT⫽Functional Reach Test, BBS⫽Berg Balance Scale, ABC⫽Activities-specific Balance Confidence Scale, TUG⫽Timed “Up & Go” Test, 6MWT⫽Six-Minute Walk Test, UPDRS⫽Unified Parkinson Disease
Rating Scale, ADL⫽Activities of Daily Living, PDQL⫽Parkinson Disease Quality of Life Scale.
b
Expressed as mean (standard deviation).
c
The value exceeded the minimal detectable change for that measure.
d
Expressed as total score.
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moderate to severe PD showed
greater changes than patients with
mild PD (Fig. 3C).
Feasibility and Safety
No adverse events were reported
during the course of the case series.
The patients adhered to the training
protocol, completing at least 24 ses-
sions during the initial 12 weeks. All
6 patients chose to continue attend-
ing the boxing training program after
the initial 12 weeks for a variety of
reasons, including enjoyment of the
program, emotional support from
other group members and trainers,
comfort in participation without fear
of judgment, and perception of im-
proved physical abilities (Tab. 1).
Only 1 patient completed more than
24 sessions within 1 of the 12-week
follow-up periods; other patients re-
ported time conflicts as the primary
reason for not attending more ses-
sions. Patient 6 attended only 3 ses-
sions between weeks 12 and 24 be-
fore discontinuing attendance in the
program (Tab. 1). He cited travel dis-
tance, conflict with work schedule,
and lack of interest in boxing as the
reasons.
Discussion
All 6 patients in this case series
showed improvements on at least 5
of the 12 outcome measures over the
baseline at the 12-week test. Except
for patient 6, all patients showed im-
provements in every outcome cate-
gory, including balance, gait, disabil-
ity, and quality of life. These positive
changes may be indicative of the
whole-body approach of the boxing
training program, which incorpo-
rated dynamic balance activities (eg,
reaching overhead when punching
speed bags) and multidirectional
reaching and stepping (while follow-
ing a trainer’s movements when
punching focus mitts). In addition,
agility drills within the circuit train-
ing regimen, such as jumping rope
and footwork activities, focused on
the initiation of movement and fast-
Table 3.
Individual Outcomes for Patients With Moderate to Severe Parkinson Disease (Hoehn-Yahr Stage 3 or 4)
Measurea
Patient 3 Patient 4 Patient 5
Baseline
12-Week
Test
24-Week
Test
36-Week
Test Baseline
12-Week
Test
24-Week
Test
36-Week
Test Baseline
12-Week
Test
24-Week
Test
36-Week
Test
FRT (cm)b11.4 (0.0) 19.9 (1.0) 16.9 (0.7) 25.4c(0.5) 18.2 (0.6) 30.9c(1.8) 31.8c(0.0) 34.3c(0.5) 26.3 (0.3) 16.9 (1.4) 27.1 (0.3) 23.3 (0.7)
BBSd46 47 51c53c48 50 51 53c50 52 53 47
ABCb63.8 (25.0) 63.8 (13.1) 65.0 (17.5) 74.4c(13.6) 63.1 (17.0) 39.4 (16.9) 65.6 (22.8) 65.0 (20.3) 52.8 (26.5) 53.8 (31.0) 65.6c(30.8) 65.0c(26.8)
TUG (s)b11.10 (0.42) 10.03c(0.24) 8.73c(0.75) 10.47 (0.05) 14.83 (0.37) 13.37c(0.70) 12.37c(0.25) 11.55c(0.33) 10.37 (0.57) 12.39 (0.50) 10.68 (0.63) 9.48c(0.66)
6MWTd307.9 323.5 324.4 389.0c247.6 273.1 313.1 330.0c372.8 373.7 335.3 472.0c
Gait speed
(m/s)b0.89 (0.06) 0.83 (0.06) 0.99 (0.09) 0.92 (0.04) 0.88 (0.04) 0.89 (0.04) 0.98 (0.04) 1.06c(0.04) 0.99 (0.03) 0.99 (0.06) 1.02 (0.05) 1.08 (0.04)
Cadence
(steps/
min)b
102.3 (3.1) 97.8 (3.0) 105.7 (3.8) 96.9 (0.7) 103.4 (1.3) 103.1 (3.4) 105.9 (2.6) 107.4 (2.0) 116.9 (2.2) 119.1 (2.1) 118.0 (4.8) 121.4 (2.8)
Stride length
(cm)b104.0 (3.6) 101.5 (5.4) 112.5 (6.4) 113.7 (5.0) 103.0 (3.7) 104.2 (2.6) 111.5 (3.9) 118.4 (2.9) 102.4 (1.2) 100.5 (5.2) 104.4 (2.9) 106.9 (2.7)
Step width
(cm)b13.7 (1.3) 13.5 (0.5) 12.9 (1.7) 12.3 (1.0) 17.3 (0.6) 18.1 (1.6) 16.2 (0.9) 17.4 (0.5) 8.9 (1.4) 7.7 (0.7) 8.2 (0.9) 9.0 (2.4)
UPDRS ADL
subscaled20 15c20 18 24 13c12c8c15 19 16 18
UPDRS
motor
subscaled
30 25 26 31 29 27 28 10c29 35 31 18c
PDQLd96 118 106 128 100 129 109 146 96 110 117 129
a
FRT⫽Functional Reach Test, BBS⫽Berg Balance Scale, ABC⫽Activities-specific Balance Confidence Scale, TUG⫽Timed “Up & Go” Test, 6MWT⫽Six-Minute Walk Test, UPDRS⫽Unified Parkinson Disease
Rating Scale, ADL⫽Activities of Daily Living, PDQL⫽Parkinson Disease Quality of Life Scale.
b
Expressed as mean (standard deviation).
c
The value exceeded the minimal detectable change for that measure.
d
Expressed as total score.
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paced changes in direction. The in-
corporation of a variety of activities
that encompassed the whole body,
as in other whole-body intervention
programs that have shown prom-
ise,
8,11,30
may have translated to the
multiple areas of functional improve-
ments shown by the patients in this
case series.
Interestingly, patients with mild PD
showed improvements earlier than
patients with moderate to severe PD,
particularly in the gait-related out-
come measures. Patients with mild
PD more often showed improve-
ments that exceeded the MDC after
the initial 12 weeks of the boxing
training program than did patients
with moderate to severe PD. These
early differences may have been due
to the ability of patients with mild
PD to tolerate and complete more rep-
etitions during the circuit training reg-
imen. This observation supports re-
search suggesting that disease severity
affects training capacity.
30
However,
patients with moderate to severe PD
did eventually show improvements in
most outcome measures, suggesting
that they required a longer training
duration to acquire the necessary
training capacity.
Another key observation of this case
series was that all patients continued
to make improvements in balance,
gait, and quality of life up to the 24-
and 36-week tests despite the reduc-
tion in attendance after the initial 12
weeks. The majority of changes that
achieved and surpassed the estab-
lished MDC values were seen at the
36-week test, indicating that long-
term training may be necessary to
attain maximal gains.
31
Patient 6 at-
tended only 3 boxing sessions after
the initial 12 weeks of the case series
but maintained or improved scores
on most outcome measures at the
24-week test, indicating a sustained
benefit of the boxing training pro-
gram. However, at the 36-week test,
patient 6 showed a decline in scores
on 5 outcome measures, perhaps be-
cause he was no longer attending
boxing sessions. The 5 patients who
continued to attend boxing sessions
during the course of the case series
showed persistent long-term bene-
Figure 1.
Changes over time in outcomes for balance. Data for patients with mild Parkinson disease (PD) are shown in black (patients 1 [P1],
P2, and P6), and data for patients with moderate to severe PD are shown in blue (P3, P4, and P5). (A) Functional Reach Test (FRT).
(B) Berg Balance Scale (BBS). (C) Activities-specific Balance Confidence Scale (ABC).
Boxing Training for Patients With Parkinson Disease
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fits, lending support for their con-
tinued use of the boxing training
program.
We were able to demonstrate that
group boxing training was feasible
for patients in this case series regard-
less of the level of PD severity. All 6
patients tolerated the 90-minute box-
ing training program. The patients
also were able to engage in other
aspects of the training program, in-
cluding donning and doffing boxing
gloves and climbing through the
ropes surrounding the boxing ring.
The decline in the number of ses-
sions completed after the initial 12
weeks for all patients may have re-
flected the typical time constraints
of daily life, as well as reduced
accountability.
The nature of a case series limits our
ability to generalize our observations
to other patients with PD and re-
stricts our ability to compare boxing
training with other rehabilitation in-
terventions. All patients in this case
series were men; therefore, the out-
comes of boxing training for women
are unknown. Additional limitations
were that the physical therapists and
physical therapist students were not
masked to the design and purpose of
the case series and that the balance-
related tools used in the case series
may have had a ceiling effect for pa-
tients with mild impairments.
21
The
MDC represents a value greater than
measurement error
22,32
; therefore, it
may not represent clinical relevance
and may limit the interpretation of
outcomes. In addition, variability in
the numbers of sessions attended by
patients during the course of the
case series may have led to differ-
ences in outcomes among patients.
This case series is the first report of
the effects of boxing training in pa-
tients with PD. Provided that further
reports demonstrate effectiveness,
the incorporation of concepts from
the whole-body boxing training reg-
imen, such as repeated punching
motions and fast-paced footwork,
into traditional physical therapy
Figure 2.
Changes over time in outcomes for gait and mobility. Data for patients with mild Parkinson disease (PD) are shown in black (patients
1 [P1], P2, and P6), and data for patients with moderate to severe PD are shown in blue (P3, P4, and P5). (A) Timed “Up & Go” Test
(TUG). (B) Six-Minute Walk Test (6MWT). (C) Gait speed.
Boxing Training for Patients With Parkinson Disease
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treatment plans for patients with PD
may be beneficial. Finding an exer-
cise program that meets the fitness
needs of a patient and that appeals to
personal interests is important for
long-term exercise adherence.
33,34
Community-based boxing training
programs for patients with PD may
be a long-term alternative to physical
therapy. Physical therapists can play
an integral role in transitioning pa-
tients from traditional rehabilitation
to such community-based programs
by serving as consultants, facilitators,
or both to maximize outcomes and
promote long-term retention.
35
Com-
parisons of boxing training with tra-
ditional exercise techniques com-
monly applied by physical therapists
and monitoring of levels of training
intensity and repetitions are needed.
Conclusion
The promising outcomes of this case
series demonstrated the feasibility of a
community-based boxing training pro-
gram for patients with PD. Despite the
progressive nature of PD, the patients
in this case series showed short-term
and long-term improvements in bal-
ance, gait, activities of daily living, and
quality of life after attending the box-
ing training program. A longer dura-
tion of training was necessary for pa-
tients with moderate to severe PD to
show maximal training outcomes. The
observations of this case series indi-
cate that an examination of the effects
of boxing training in patients with PD
is warranted.
All authors provided concept/idea/project
design, writing, and data collection and
analysis. The authors thank the patients for
their time and dedication. They express their
gratitude to Kristina Follmar and the Rock
Steady Boxing Foundation for their cooper-
ation in carrying out this project.
This case series was approved by the Institu-
tional Review Board at the University of
Indianapolis.
Some of the observations of this case series
were presented at the Combined Sections
Meeting of the American Physical Therapy
Association; February 17–20, 2010; San Di-
ego, California; and at the XVIII WFN World
Congress on Parkinson’s Disease and Related
Figure 3.
Changes over time in outcomes for Parkinson disease (PD)–specific disability and quality of life. Data for patients with mild PD are
shown in black (patients 1 [P1], P2, and P6), and data for patients with moderate to severe PD are shown in blue (P3, P4, and P5).
(A) Unified Parkinson Disease Rating Scale (UPDRS) activities of daily living (ADL) subscale. (B) UPDRS motor examination subscale.
(C) Parkinson Disease Quality of Life Scale (PDQL).
Boxing Training for Patients With Parkinson Disease
January 2011 Volume 91 Number 1 Physical Therapy f141
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Disorders; December 13–16, 2009; Miami
Beach, Florida.
This article was submitted April 22, 2010, and
was accepted August 27, 2010.
DOI: 10.2522/ptj.20100142
References
1Jankovic J. Parkinson’s disease: clinical fea-
tures and diagnosis. J Neurol Neurosurg
Psychiatry. 2008;79:368–376.
2Dibble LE, Hale TF, Marcus RL, et al. High-
intensity resistance training amplifies mus-
cle hypertrophy and functional gains in
persons with Parkinson’s disease. Mov
Disord. 2006;21:1444–1452.
3Herman T, Giladi N, Gruendlinger L, Haus-
dorff JM. Six weeks of intensive treadmill
training improves gait and quality of life in
patients with Parkinson’s disease: a pilot
study. Arch Phys Med Rehabil. 2007;88:
1154–1158.
4Hirsch MA, Toole T, Maitland CG, Rider
RA. The effects of balance training and
high-intensity resistance training on per-
sons with idiopathic Parkinson’s disease.
Arch Phys Med Rehabil. 2003;84:1109–
1117.
5Rodrigues de Paula F, Teixeira-Salmela LF,
Coelho de Morais Faria CD, et al. Impact of
an exercise program on physical, emo-
tional, and social aspects of quality of life
of individuals with Parkinson’s disease.
Mov Disord. 2006;21:1073–1077.
6Schenkman M, Hall D, Kumar R, Kohrt
WM. Endurance exercise training to im-
prove economy of movement of people
with Parkinson disease: three case reports.
Phys Ther. 2008;88:63–76.
7Yousefi B, Tadibi V, Khoei AF, Montazeri
A. Exercise therapy, quality of life, and
activities of daily living in patients with
Parkinson disease: a small scale quasi-
randomised trial. Trials. 2009;10:67.
8Hackney ME, Kantorovich S, Levin R, Ear-
hart GM. Effects of tango on functional
mobility in Parkinson’s disease: a prelimi-
nary study. J Neurol Phys Ther. 2007;31:
173–179.
9Klein PJ, Rivers L. Taiji for individuals with
Parkinson disease and their support part-
ners: a program evaluation. J Neurol Phys
Ther. 2006;30:22–27.
10 Schmitz-Hubsch T, Pyfer D, Kielwein K,
et al. Qigong exercise for the symptoms of
Parkinson’s disease: a randomized, con-
trolled pilot study. Mov Disord. 2006;21:
543–548.
11 Hackney ME, Earhart GM. Tai Chi im-
proves balance and mobility in people
with Parkinson disease. Gait Posture.
2008;28:456–460.
12 Li F, Harmer P, Fisher KJ, et al. Tai Chi-
based exercise for older adults with Par-
kinson’s disease: a pilot-program evalua-
tion. J Aging Phys Act. 2007;15:139–151.
13 Guidetti L, Musulin A, Baldari C. Physio-
logical factors in middleweight boxing
performance. J Sports Med Phys Fitness.
2002;42:309–314.
14 King LA, Horak FB. Delaying mobility dis-
ability in people with Parkinson disease
using a sensorimotor agility exercise pro-
gram. Phys Ther. 2009;89:384–393.
15 Schenkman M, Cutson TM, Kuchibhatla M,
et al. Exercise to improve spinal flexibility
and function for people with Parkinson’s
disease: a randomized, controlled trial.
J Am Geriatr Soc. 1998;46:1207–1216.
16 Protas EJ, Mitchell K, Williams A, et al. Gait
and step training to reduce falls in Parkin-
son’s disease. Neurorehabilitation. 2005;
20:183–190.
17 Ridgel AL, Vitek JL, Alberts JL. Forced, not
voluntary, exercise improves motor
function in Parkinson’s disease patients.
Neurorehabil Neural Repair. 2009;23:
600–608.
18 Kravitz L, Greene L, Burkett Z, Wong-
sathikun J. Cardiovascular response to
punching tempo. J Strength Cond Res.
2003;17:104–108.
19 Bellinger B, St Clair Gibson A, Oelofse A,
et al. Energy expenditure of a noncontact
boxing training session compared with
submaximal treadmill running. Med Sci
Sports Exerc. 1997;29:1653–1656.
20 Goetz CG, Poewe W, Rascol O, et al.
Movement Disorder Society Task Force re-
port on the Hoehn and Yahr staging scale:
status and recommendations. Mov Disord.
2004;19:1020–1028.
21 Duncan PW, Weiner DK, Chandler J, Stu-
denski S. Functional reach: a new clinical
measure of balance. J Gerontol. 1990;45:
M192–M197.
22 Steffen T, Seney M. Test-retest reliability
and minimal detectable change on balance
and ambulation tests, the 36-Item Short-
Form Health Survey, and the Unified Par-
kinson Disease Rating Scale in people
with parkinsonism. Phys Ther. 2008;88:
733–746.
23 Qutubuddin AA, Pegg PO, Cifu DX, et al.
Validating the Berg Balance Scale for pa-
tients with Parkinson’s disease: a key to
rehabilitation evaluation. Arch Phys Med
Rehabil. 2005;86:789–792.
24 Powell LE, Myers AM. The Activities-
specific Balance Confidence (ABC) Scale. J
Gerontol A Biol Sci Med Sci. 1995;50:
M28–M34.
25 Morris S, Morris ME, Iansek R. Reliability of
measurements obtained with the Timed
“Up & Go” Test in people with Parkinson
disease. Phys Ther. 2001;81:810–818.
26 Bilney B, Morris M, Webster K. Concur-
rent related validity of the GAITRite walk-
way system for quantification of the spatial
and temporal parameters of gait. Gait Pos-
ture. 2003;17:68–74.
27 Movement Disorder Society Task Force on
Rating Scales for Parkinson’s Disease. The
Unified Parkinson’s Disease Rating Scale
(UPDRS): status and recommendations.
Mov Disord. 2003;18:738–750.
28 Hobson P, Holden A, Meara J. Measuring
the impact of Parkinson’s disease with the
Parkinson’s Disease Quality of Life Ques-
tionnaire. Age Ageing. 1999;28:341–346.
29 De Boer AGEM, Wijker W, Speelman JD,
De Haes JCJM. Quality of life in patients
with Parkinson’s disease: development of
a questionnaire. J Neurol Neurosurg Psy-
chiatry. 1996;61:70–74.
30 Farley BG, Koshland GF. Training BIG to
move faster: the application of the speed-
amplitude relation as a rehabilitation strat-
egy for people with Parkinson’s disease.
Exp Brain Res. 2005;167:462–467.
31 Nieuwboer A, Kwakkel G, Rochester L,
et al. Cueing training in the home im-
proves gait-related mobility in Parkinson’s
disease: the RESCUE trial. J Neurol Neuro-
surg Psychiatry. 2007;78:134–140.
32 Haley SM, Fragala-Pinkham MA. Interpret-
ing change scores of tests and measures
used in physical therapy. Phys Ther. 2006;
86:735–743.
33 Morris ME, Martin CL, Schenkman ML.
Striding out with Parkinson disease:
evidence-based physical therapy for gait
disorders. Phys Ther. 2010;90:280–288.
34 Rhodes RE, Martin AD, Taunton JE, et al.
Factors associated with exercise adher-
ence among older adults: an individual
perspective. Sports Med. 1999;28:
397–411.
35 Rimmer JH. Health promotion for people
with disabilities: the emerging paradigm
shift from disability prevention to preven-
tion of secondary conditions. Phys Ther.
1999;79:495–502.
36 Jankovic J, McDermott M, Carter J, et al.
Variable expression of Parkinson’s dis-
ease: a base-line analysis of the DATATOP
cohort. The Parkinson Study Group. Neu-
rology. 1990;40:1529–1534.
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doi: 10.2522/ptj.20100142
Originally published online November 18, 2010
2011; 91:132-142.PHYS THER.
Schaneman
Lindsay Conn, Kendra Davis, Nicole Lewis and Katie
Stephanie A. Combs, M. Dyer Diehl, William H. Staples,
A Case Series
Boxing Training for Patients With Parkinson Disease:
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