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The Effect of Backward Locomotion Training on the Body Composition and Cardiorespiratory Fitness of Young Women

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Abstract

This study investigated the effect of a backward training program on the physical and fitness condition of young women. Twenty-six healthy female university students (aged 18 - 23 years) took part in three different baseline tests: body composition, a submaximal treadmill test, and a 20-m shuttle run test. Subjects were divided into a training group (n = 13) and a control group (n = 13). The training group completed a six-week backward run/walk training program. The control group was restricted to their daily activities similar to the four weeks prior to the onset of the baseline tests. The training group showed a significant (p = 0.01) decrease in O(2) consumption during both submaximal forward and backward exercise on the treadmill (32 % decrease during backward and 30 % decrease during forward exercise). A significant (p = 0.01) decrease in percentage body fat (2.4 %), a 19.7 % decrease in the sum of skinfolds (p = 0.001) and significantly (p = 0.013) improved predicted VO(2max) values from the forward 20-m shuttle run test (5.2 %) were also found in the case of the training group. The findings suggest that backward walk/run training improves cardiorespiratory fitness for both forward and backward exercise and causes significant changes in body composition in young women.
Introduction
In many sports, particularly team sports such as hockey, netball,
basketball, soccer, rugby, and most racquet sports, players must
be able to move forward, backward, and laterally with speed and
agility. A successful training program for these athletes will
therefore include drills and movements in many different direc-
tions.
Various movement patterns, specifically backward walking and
running, have not only been suggested for use in sports condi-
tioning programs, but also for the rehabilitation of overuse run-
ning injuries and knee joint pathology [12]. The rationale for the
latter is that backward locomotion increases the strength and
power of the quadriceps muscles [14,19, 23], while reducing the
compressive forces at the patellofemoral joint [13], prevent over-
stretching of the anterior cruciate ligament (ACL) during quadri-
ceps action [19] and decrease force absorption [14].
To date, research has focused mainly on the biomechanics of
backward walking and running [7,9,14], as well as the compari-
son of the energy cost of backward and forward movement
[5, 8,12, 25]. It has been established that backward walking and
running require increased metabolic cost and cardiopulmonary
demand compared with forward walking and running at the
same constant speed [12], as well as at the same speed, but dif-
Abstract
This study investigated the effect of a backward training program
on the physical and fitness condition of young women. Twenty-
six healthy female university students (aged 18 ±23 years) took
part in three different baseline tests: body composition, a sub-
maximal treadmill test, and a 20-m shuttle run test. Subjects
were divided into a training group (n = 13) and a control group
(n = 13). The training group completed a six-week backward
run/walk training program. The control group was restricted to
their daily activities similar to the four weeks prior to the onset
of the baseline tests. The training group showed a significant
(p = 0.01) decrease in O
2
consumption during both submaximal
forward and backward exercise on the treadmill (32% decrease
during backward and 30% decrease during forward exercise). A
significant (p = 0.01) decrease in percentage body fat (2.4%), a
19.7% decrease in the sum of skinfolds (p = 0.001) and signifi-
cantly (p = 0.013) improved predicted V
Ç
O
2max
values from the for-
ward 20-m shuttle run test (5.2%) were also found in the case of
the training group. The findings suggest that backward walk/run
training improves cardiorespiratory fitness for both forward and
backward exercise and causes significant changes in body com-
position in young women.
Key words
Retro exercise ´ anthropometry ´ V
Ç
O
2max
´ muscle strength
Training & Testing
214
Affiliation
1
Department of Medical Physiology and Biochemistry, Faculty of Health Sciences, University of Stellenbosch,
Tygerberg, Cape Town, South Africa
2
Department of Sport Science, University of Stellenbosch, Matieland, Stellenbosch, South Africa
Correspondence
Dr. E. Terblanche ´ Department of Medical Physiology and Biochemistry, Faculty of Health Sciences,
University of Stellenbosch ´ PO Box 19063 ´ Tygerberg 7505, Cape Town ´ South Africa ´
Phone: + 27219389531 ´ Fax: + 27219389476 ´ E-mail: et2@sun.ac.za
Accepted after revision: February 9, 2004
Bibliography
Int J Sports Med 2005; 26: 214±219 Georg Thieme Verlag KG ´ Stuttgart ´ New York ´
DOI 10.1055/s-2004-820997 ´ Published online August 26, 2004 ´
ISSN 0172-4622
E. Terblanche
1
C. Page
1
J. Kroff
1
R. E. Venter
2
The Effect of Backward Locomotion Training on the
Body Composition and Cardiorespiratory Fitness of
Young Women
ferent treadmill elevations [5]. The differences in metabolic costs
have been attributed to (a) increased stride frequency and de-
creased stride length during backward walking compared to for-
ward walking [12] and (b) the concentric actions of the quadri-
ceps muscle group during backward walking, which has been
shown to have a higher energy cost than eccentric muscular
work [1].
It has been suggested that athletes could follow a backward
walking/running training program during rehabilitation, and
still exercise at an intensity that is sufficient to maintain cardio-
vascular fitness levels [12, 21]. Myatt et al. [21] and Clarkson et al.
[8] reported that both men and women can exercise at the rec-
ommended training intensities of 50 ±85% of V
Ç
O
2peak
or 65 ±90%
of maximal heart rate to develop and maintain cardiorespiratory
fitness. However, the cardiovascular and metabolic effects of a
progressive backward locomotion training program have not yet
been described or quantified.
The aims of this study were to determine whether a backward
walk-and-run training program (a) will improve the body com-
position and (b) will result in increased aerobic fitness in young,
healthy women.
Methodology
Subjects
Healthy, habitually active women, who did not participate in any
organized or competitive sport, volunteered to participate in the
study. Following a detailed explanation of the tests involved and
the training program, all subjects (n = 26) gave their written, in-
formed consent. None of the subjects experienced any activity-
limiting lower extremity dysfunction that may have influenced
their responses to the physical tests or training program. Sub-
jects were divided into a training group (n = 13) and a control
group (n = 13) and all subjects were tested before and after the
6-week intervention (training program). The experimental pro-
tocol was approved by the Ethics Committee of the Faculty of
Health Sciences, University of Stellenbosch.
Testing procedures
All tests were conducted indoors on four separate days, but
within one week. Tests included an anthropometric assessment
and isokinetic test (first visit), a submaximal treadmill test (sec-
ond visit), and a 20-m progressive shuttle run test (third and
fourth visit).
Anthropometric assessment
Height (to the nearest cm) and weight (to the nearest 0.1 kg)
were recorded with subjects dressed in exercise clothes and
without shoes. Skinfold measurements (to the nearest mm) were
obtained from seven sites (biceps, triceps, subscapular, supra-
iliac, front thigh, mid calf, abdominal) on the right side of the
body by the same investigator using a Harpenden skinfold cali-
per. The investigator was blinded to the individual subjects
group assignment for both baseline and follow-up tests. Percent
body fat was calculated using the Durnin-Womersley equation
[11]. Standing height and weight was used to calculate BMI
(weight, kg)/(height, m
2
).
Isokinetic test
Knee flexor and extensor strength was measured on the Biodex
System 3 isokinetic dynamometer (Biodex Corporation, Shirley,
NY). Drouin et al. [10] have shown that the Biodex System 3 is
both reliable (trial-to-trial reliability: r = 0.99; day-to-day reli-
ability: r = 0.99) and valid (r = 0.99). Before the measurement ses-
sion, the subjects received instruction in the performance of
maximal isokinetic efforts and were given 3 practice efforts.
The dynamometer placement was adjusted for each leg so that
the axis of rotation of the knee joint was aligned with the axis of
rotation of the dynamometer rod. The torso, hip, and thigh of the
subject were restrained with straps for stabilization and to pre-
vent any other movement that could affect the measurement.
Torque measures were corrected for the effects of gravity on the
lower leg and the dynamometers resistance pad. The torque out-
put on the dynamometer was checked with a calibration weight
on a regular basis throughout the study. Subjects performed five
repetitions at an angular speed of 608/s with a 10-second rest
period after each effort. Subjects were verbally encouraged
throughout the test to ensure maximal performance. The highest
torque reading of the five attempts for both knee extension and
flexion was recorded.
Submaximal test
The submaximal walk and run test was performed on a treadmill.
The interval protocol consisted of a 2-min forward walk at a
treadmill speed of 4 km ´h
±1
, a 2-min rest interval, and a 2-min
forward run at a treadmill speed of 7 km´ h
±1
. This was followed
by a 10-min rest before walking and running backwards using
the same protocol. During the exercise test, expired gases were
collected and analyzed continuously using the Cortex Metalyzer
3 B cardiopulmonary system (Cortex Biophysik, Leipzig, Ger-
many). Before each testing session, the gas analyzers were cali-
brated against a precision analyzed gas mixture (CO
2
: 3.5%; O
2
:
17.8 %). The volume transducer was calibrated with a 3-L syringe.
The cardiorespiratory variables measured included oxygen up-
take (V
Ç
O
2
ml ´ kg
±1
´min
±1
), carbon dioxide production (V
Ç
CO
2
l´min
±1
), and minute ventilation (VE l ´ min
±1
). Heart rate was
measured by telemetry (Polar Heart Rate Monitor, Kempele, Fin-
land) and automatically interfaced with the other physiological
variables via the metalyzer software. Five capillary blood sam-
ples were obtained by means of a finger prick and blood lactate
concentration was measured using the Accusport Lactate Ana-
lyzer (Boehringer Mannheim, Germany) (validity = 0.96 and reli-
ability = 0.99) [4]. Samples were taken at rest and immediately
after each of the four exercise intervals.
20-m progressive shuttle run test
Subjects performed two 20-m shuttle run tests (one forward and
one backward), on a flat, hard surface on separate days. Subjects
were required to run repeatedly between two beacons, 20 meters
apart. A portable cassette player with an audiocassette set the
pace for running between the beacons. Each subject was allowed
to voluntarily cease the test at fatigue or was stopped by the ob-
server/researcher when she failed to reach the beacon before or
at the ªbleepº on two occasions. The level and shuttle that was
completed was noted as the score achieved. Predicted V
Ç
O
2max
values were calculated from the forward run scores using the fol-
lowing formula: V
Ç
O
2max
,ml´kg
±1
´min
±1
= 31.025 + 3.238 (speed,
Terblanche E et al. Effect of Backward Locomotion Training ¼ Int J Sports Med 2005; 26: 214 ± 219
Training & Testing
215
km ´ h
±1
) ± 3.248 (age, yr) + 0.1536 (age speed) [18]. The validity
and test-retest reliability of the 20-m shuttle run test for adults
were reported as 0.90 and 0.95, respectively [18].
Training program
The training group followed a backward training program for six
weeks, consisting of three sessions per week for a total of 18 ses-
sions. The duration of the sessions was progressively increased
over the period of six weeks. The first three sessions were 15
minutes long, with the primary aim to familiarize the partici-
pants with the mode of training and to ensure that everyone will
cope with backward walking. The next week started with 25
minutes per session and the duration of the sessions was in-
creased by 5 minutes per week, ending with 45 minutes in the
last week. In total, 40% of the exercise time consisted of back-
ward walking, while the majority (60%) of the training program
consisted of backward running exercises. The exercise sessions
took place at the athletics track, except for one session during
the first week that took place indoors due to adverse weather
conditions.
All training sessions took place in the afternoon at 17: 00. There
were always two supervisors present to take heart rate measure-
ments at the start and end of the session, to assist in counting the
number of laps completed around the track, to control the dura-
tion of the session with a stopwatch and to monitor the session
in general. The training group started off together, but each indi-
vidual was allowed to walk at her own pace. Participants were
asked to try and increase the number of laps they could complete
around the athletics track. The track was divided into four sec-
tions and completed laps were for example recorded as six and
a half laps or five and a quarter laps. The participants were regu-
larly informed of the time elapsed during the session. Subjects in
the control group were asked to avoid any major changes in their
diet and/or exercise regimens while participating in the study.
Statistical analysis
Descriptive statistics were calculated as the means and standard
deviations (mean SD). Data were analyzed using a 2 2 ANOVA
(group vs. pre/post measurement) for repeated measures. Differ-
ences detected by the ANOVAs were located with Scheffe post hoc
tests. Statistical significance was accepted at the p < 0.05 level.
Results
Table 1 shows the physical characteristics of the trained and un-
trained groups, both before and after the 6-week intervention.
There were no statistically significant differences in age, height,
weight, sum of skinfolds, % body fat, and BMI between the train-
ed and untrained groups before the start of the intervention. The
trained group showed statistically significant decreases in skin-
fold thickness (19.6%; p = 0.001) and % body fat (2.4 %; p = 0.01)
after participation in the 6-week backward training program.
There were no statistically significant changes in the physical
characteristics of the untrained groups.
The predicted V
Ç
O
2max
-values calculated from the results of the
20-m forward shuttle run test are presented in Table 1. The train-
ed group showed a statistically significant increase of 5.2%
(p = 0.01) in maximal oxygen uptake following the 6-week back-
ward training program. This improvement in maximal aerobic
capacity followed after the trained group completed significantly
more shuttles during both the forward (57 SD 19.5 shuttles vs.
63 SD 17.7 shuttles; p = 0.03) and backward (15 SD 6.1 shut-
tles vs. 19 SD 6.1 shuttles; p = 0.002) 20-m shuttle run tests
after the training program (Fig. 1).
On average, the untrained group completed one more shuttle in
the forward shuttle run during the follow-up measurements
(55 SD 13.5 shuttles vs. 56 SD 18.5 shuttles), but could not im-
prove on their performance in the backward shuttle run test
(12 SD 15.1 shuttles vs. 12 SD 13.7 shuttles). There was also
no significant change in predicted V
Ç
O
2max
-values following the
6-week period (Table 1).
Table 1 Mean values ( SD) for physical measures of the trained and
untrained groups before and after the 6-week training pro-
gram
Trained group (n = 13) Untrained group (n = 13)
Measures Before After Before After
Age (yrs) 21 0.8 ± 20 1.6 ±
Height (cm) 166 4.9 ± 168 6.6 ±
Weight (kg) 61 7.9 61 6.8 60 10.8 60 11.4
BMI 22 1.9 22 1.6 21 3.5 21 3.4
S Skinfolds
(mm)
112 27.4 90 18.9* 110 47.6 106 45.5
Body fat (%) 26 4.0 23 3.5* 24 6.7 23 6.3
V
Ç
O
2max
(ml ´ kg
±1
´
min
±1
)#
38 6.6 40 5.6* 38 4.6 38 6.0
# Predicted V
Ç
O
2max
derived from 20-m shuttle test. * Significant change (p = 0.01)
Forward 20m Shuttle Run
*
#
0
10
20
30
40
50
60
70
80
pre-training post-training
numb er of shu ttles
Trained group Untrained group
Backward 20m Shuttle Run
0
5
10
15
20
25
30
pre-training post-training
num ber o f sh uttles
Trained group Untrained group
Fig.1 Number of shuttles (means SD)
completed during the forward (* p = 0.03)
and backward (# p = 0.002) shuttle run tests
before and after the 6-week training pro-
gram.
Terblanche E et al. Effect of Backward Locomotion Training ¼ Int J Sports Med 2005; 26: 214 ± 219
Training & Testing
216
The cardiorespiratory and metabolic responses of the women
during the submaximal treadmill tests are summarized in Table
2. There was a statistically significant (p = 0.01) decrease in oxy-
gen consumption in the trained group for both forward and back-
ward exercise at a walking speed of 4 km ´h
±1
and a running
speed of 7 km ´h
±1
. Although there were decreases in heart rate
and blood [La] in all four exercise conditions in the trained group,
this decrease was only significant (p = 0.01) for backward walk-
ing at 4 km ´h
±1
(HR: 131 SD 19.5 vs. 121 SD 13.7) and back-
ward running at 7 km´ h
±1
([La]: 5.3 SD 1.8 vs. 4.5 SD 1.8).
There were no statistically significant changes in the exercise re-
sponses of the untrained group for either forward or backward
exercise.
Table 3 shows that the backward training program had little or
no effect on the isokinetic strength of the quadriceps and ham-
strings muscle groups. The trained group showed statistically
significant (p = 0.04) improvements in the peak torque for both
the left and right hamstring muscles, but no significant change
in the peak torque of the quadriceps muscles. Although the train-
ed group showed increases in the total work done by both the left
and right hamstrings, the change was only significant (p = 0.006)
for the left leg (409 SD 76.4 J vs. 443 SD 88.0 J). Furthermore,
the untrained group also showed significant improvements in
total work done by both the left and right hamstring muscles
(p = 0.006). There were no significant changes in any of the con-
centric strength measurements for the quadriceps muscles in ei-
ther of the groups.
Discussion
Forward locomotion (walking and running) is probably one of
the most common modes of aerobic conditioning and numerous
studies have shown the benefits of different kinds of forward
walk/run training programs [16, 20]. Backward locomotion is a
training technique often used in team sports to increase coordi-
nation and endurance [22], however, the effect of a backward
walk/run training program on the aerobic fitness of healthy indi-
viduals has not been quantified before. The results of this study
provide, for the first time, evidence that backward locomotion
can improve cardiorespiratory fitness and possibly lead to posi-
tive body composition changes in young women.
In order to develop and maintain cardiorespiratory fitness, it is
recommended that both men and women exercise at intensities
that correspond to 65 ±90% of maximal heart rate or 50 ±85% of
V
Ç
O
2peak
[22]. Although it was not possible to monitor exercise in-
tensity during the backward training sessions, the program was
designed along the same principles as for any forward training
program. Both the intensity and duration of the individual ses-
Table 2 Mean values ( SD) for the forward/backward exercise submaximal measures of the trained and untrained groups before and after the
6-week training program
Trained group (n = 13) Untrained group (n = 13)
Measures Before After Before After
Forward exercise
4km´h
±1
±V
Ç
O
2
(ml ´ kg
±1
´min
±1
) 15 5.0 10 1.3 * 13 5.2 11 0.8
±HR(b´min
±1
) 109 14.3 103 12.1 105 15.1 109 14.8
±VE(L´min
±1
) 16 4.3 17 3.2 16 7.2 17 5.5
± La (mmol ´L
±1
) 2.8 1.2 2.6 1.0 2.4 0.7 2.8 0.8
7km´h
±1
±V
Ç
O
2
(ml ´ kg
±1
´min
±1
) 33 9.2 23 2.0 * 29 9.6 26 6.6
±HR(b´min
±1
) 145 13.6 143 12.1 144 10.8 145 11.8
±VE(L´min
±1
) 34 8.5 35 6.4 33 11.9 33 10.6
± La (mmol ´L
±1
) 3.5 1.7 2.9 1.0 3.1 0.9 3.4 0.9
Backward exercise
4km´h
±1
±V
Ç
O
2
(ml ´ kg
±1
´min
±1
) 22 6.2 15 2.4 * 19 9.1 14 2.1
±HR(b´min
±1
) 131 19.5 121 13.8* 124 13.9 127 16.2
±VE(L´min
±1
) 24 6.1 23 4.5 23 8.2 22 8.3
± La (mmol ´L
±1
) 3.2 1.3 2.7 0.7 3.1 1.1 3.1 0.6
7km´h
±1
±V
Ç
O
2
(ml ´ kg
±1
´min
±1
) 40 13.4 27 2.5 * 37 14.5 30 6.6
±HR(b´min
±1
) 165 14.3 163 12.7 163 13.0 166 11.7
±VE(L´min
±1
) 48 10.3 50 13.3 48 19.6 53 19.9
± La (mmol ´L
±1
) 5.3 1.9 4.5 1.7* 4.6 1.1 4.9 1.0
* Significant change (p = 0.01)
Terblanche E et al. Effect of Backward Locomotion Training ¼ Int J Sports Med 2005; 26: 214 ± 219
Training & Testing
217
sions were increased steadily over the six weeks and in the last
week the women exercised for 45 min per session.
The most important, and novel, finding of this study was that the
women following the 6-week training program significantly im-
proved their aerobic fitness. This was evident in both the sub-
maximal treadmill tests and the endurance test (20-m shuttle
run). The results of the submaximal treadmill tests indicate that
the trained women improved their economy of motion during
backward walking at 4 km´ h
±1
and running at 7 km´ h
±1
.Itis
known that backward exercise requires a higher metabolic de-
mand than forward exercise at the same speed, primarily due to
the novelty of the task and mainly concentric muscle contrac-
tions during backward walking and running. However, Childs et
al. [6] demonstrated that the metabolic cost of backward exer-
cise decreases within 12 exercise sessions, due to the fact that in-
dividuals become more accustomed to this novel task.
The subjects in this study trained for a total of 18 sessions and
one could therefore argue that the improvement in the submax-
imal backward exercise is attributed to familiarization of the
task. However, the trained group also showed a significant de-
creased economic cost during forward exercise at 4 and
7km´h
±1
. Furthermore, although not statistically significant,
there was a tendency for a reduced accummulation of blood lac-
tate during both backward and forward exercise, while it was un-
changed in the control group. From these results it can be con-
cluded that the trained subjects became more economical, not
only because they were more familiar with backward exercise,
but also because they were fitter.
It may be speculated that the improvement in forward locomo-
tion in response to a backward training program is due to the
high metabolic cost and cardiopulmonary demand of backward
locomotion. Our data suggest that the changes can possibly be
attributed to changes in muscle metabolism, as suggested by
the blood lactate values during the submaximal walk/run test,
rather than changes in central factors, i.e. cardiac output. Pre-
vious studies [5,12] have shown that backward walking, compar-
ed with forward walking, resulted in greater respiratory and
metabolic responses than cardiovascular responses. These find-
ings therefore also support a possible peripheral, rather than a
central adaptation to backward running training.
The trained group was also able to improve their maximal endur-
ance capacity (Table 1 and Fig. 1). Again, these improvements
were not limited to backward exercise. The trained group also
improved their aerobic capacity for forward running. They
showed a statistically significant increase in the number of
shuttles completed during the forward shuttle run test, which
resulted in a significantly higher predicted V
Ç
O
2max
-value
(38.4 SD 6.6 ml´ kg
±1
´min
±1
vs. 40.4 SD 5.6 ml ´kg
±1
´min
±1
).
Given that backward walking requires 38± 119 % more energy
consumption than forward walking at the same speed [21], and
that the subjects improved their walking and running economy
for both forward and backward exercise, this improvement in
aerobic capacity may be expected.
The improvement in aerobic fitness in the trained group was fur-
ther accompanied by a decrease in skinfold thickness and per-
centage body fat, while there were no significant changes in
these measurements in the control group. As already indicated,
backward exercise is metabolically a far more demanding activ-
ity than forward exercise and it is therefore not inconceivable
that our backward training program led to substantial energy ex-
penditure. Hawley [15] stated that low intensity exercise
strongly stimulates lipolysis from peripheral adipocytes, while
the rate of fat oxidation is highest during moderate activities. It
has also been reported that exercise training decreases body fat
and maintains or increases body fat-free mass, while dieting is
more effecting in reducing body weight [3, 24]. We therefore
speculate that our backward training program was probably of
sufficient intensity to promote fat loss, while maintaining fat-
free body mass.
Although the subjects diets were not monitored, they were re-
quested not to change their eating patterns during the study.
The majority of the subjects reside and have their meals in stu-
dent residences on campus, which suggests that it is unlikely
that their diets changed over the 6-week study period and that
Table 3 Mean values ( SD) for isokinetic measures for the quadriceps and hamstrings muscles of the trained and untrained groups before and
after the 6-week training program
Trained group (n = 13) Untrained group (n = 13)
Left Right Left Right
Before After Before After Before After Before After
Quadriceps
Peak torque (N-m) 166 22.2 167 24.7 168 26.1 171 18.7 146 47.0 143 51.4 149 45.8 149 54.7
Total work (J) 736 115.0 737 102.0 735 130.0 770 88.2 687 100.4 746 144.0 703 121.0 766 143.5
Work fatigue (%) 35 58.8 22 8.3 15 14.2 20 7.5 21 13.5 27 12.4 17 23.8 25 13.5
Hamstrings
Peak torque (N-m) 82 13.7 89 13.5* 88 15.8 95 12.1# 71 19.8 78 23.3 75 23.9 81 27.1
Total work (J) 409 76.5 443 87.8* 448 88.2 482 67.0 375 84.2 459 117.2# 413 95.5 477 92.6#
Work fatigue (%) 25 7.7 26 4.2 24 6.0 24 6.0 24 10.2 31 11.9 16 13.4 25 7.9
* Significant change (p = 0.04); # Significant change (p = 0.006)
Terblanche E et al. Effect of Backward Locomotion Training ¼ Int J Sports Med 2005; 26: 214 ± 219
Training & Testing
218
it was the same for the trained and control groups. However,
since the participants diets were not monitored during the
study, it remains speculative that their eating patterns did not
change. This is therefore an important limitation of the study.
If the subjects eating patterns have in fact not changed during
the course of the study, it is encouraging that the trained group
showed significant changes in body composition within a rela-
tively short time period. This would suggest that the backward
training program was of sufficient duration and intensity to in-
duce these changes. It remains to be seen whether backward
training causes more, or less, fat loss in women compared to for-
ward training.
Although it has been suggested that backward running training
increases quadriceps power and strength [19, 23], similar effects
were not found in this study. Mackie and Dean [19] trained their
subjects for three months on a treadmill and showed that the
power of the subjects legs increased significantly, while the
strength of the knee flexors and extensors decreased in most
subjects. Threlkeld et al. [23] found that backward running (as
part of a forward running program over 8 weeks) increased the
peak concentric isokinetic torque of the quadriceps at angular
velocities of 758 and 1208/s, but not at 1808 or 2108/s. The mecha-
nism for the improvement in quadriceps strength is probably
related to the isometric and concentric nature of the muscle ac-
tions during backward running [11], as well as the fact that the
leg muscles are active for a longer sustained period during back-
ward locomotion compared to forward locomotion [11,17].
In a similar study to ours, using a 6-week backward running
training program, Anderson et al. [2] also found no significant
improvements in either quadriceps or hamstrings muscle
strength (concentric and eccentric). It is therefore possible that
a 6-week training program is marginally too short, or that the
running program must be conducted over variable terrain and
not only on a flat surface (as in the case of Andersons study and
this study). Other reasons why we could not show conclusively
whether backward running training improves muscle strength,
or not, are the small sample size and large standard deviations
of our results.
The importance of maintaining a healthy lifestyle is continuously
emphasized by health authorities and those involved in the fit-
ness industry. However, it is also a reality that many competitive
and recreational runners will suffer debilitating injuries, particu-
larly affecting the knee joints, as a direct consequence of their
running. The results of this study confirm previous suggestions
that backward exercise may be used to maintain or improve an
individuals aerobic fitness level who are unable to engage in for-
ward exercise [13,14, 23]. However, backward locomotion is not
limited only to rehabilitation programs, but may also be a useful
supplement to traditional forward running training programs.
Acknowledgements
The authors extend their gratitude to Brendan Thomas and Willie
Louw for their excellent assistance and to all the ladies partici-
pating in this project.
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Training & Testing
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... Concerning BR prescription, most studies relied on short-duration sprints, with the speed being self-selected by participants (UTHOFF et al., 2019;UTHOFF et al., 2018), without training intensity individualization. This means that no meticulous control of the training intensities was adopted (UTHOFF et al., 2018;ORDWAY et al., 2016;TERBLANCHE et al., 2005), which can lead to under or overestimation of the adequate intensities. ...
... In that study the participants improved their 3-km performance by 5.0%. This improvement may be associated with the increase in cardiorespiratory fitness after the BRT program, as shown by other studies which found that aerobic fitness can be improved with BRT as the cardiopulmonary demands are relatively higher than during FR (UTHOFF et al., 2018;ORDWAY et al., 2016;TERBLANCHE et al., 2005). It is likely that the lower increase in T5km can be explained by the lower CUADERNOS DE EDUCACIÓN Y DESARROLLO,Portugal,v.16,n.2,specificity of BR in terms of muscle recruitment patterns and coordination (UTHOFF et al., 2018;FLYNN, SOUTAS-LITTLE, 1995). ...
... This means that not only the type of locomotion drives adaptations to training, but intensity also matters.On the other hand, the present study corroborates the results ofTerblanche and Venter (2009), who found a higher performance in the CMJ test for the FRT group (moderate effect) compared to the BRT group (trivial effect) in young female netball athletes. However, it is important to mention that most previous studies(UTHOFF et al., 2020;SWATI et al., 2012;TERBLANCHE et al., 2005) disagree with our findings, as improvements were reported in vertical jump height in BRT groups.The responses related to the 20-m sprint test did not reveal pre-and posttraining changes in any of the groups. This finding is different from the results reported byUthoff et al. (2020). ...
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... Given the unique demands of BR on musculotendinous functioning, it has been implemented as a training protocol to enhance athletic qualities such as sprinting performance (Uthoff et al., 2020), CoD speed (Terblanche & Venter, 2009), and jumping height (Uthoff et al., 2020). Besides improving these relatively highvelocity movements related to maximal neuromuscular capabilities, BR training has also been found to promote positive adaptations in cardiovascular fitness (Ordway et al., 2016;Terblanche et al., 2005). Since BR results in approximately 28-35% greater energy expenditure compared to FR at similar running velocities (Conti, 2009;Rasica et al., 2020), it may be a particularly effective method for stimulating positive adaptations in athletic qualities that are dependent on cardiorespiratory capabilities (Uthoff et al., 2019), such as RSA (Bishop et al., 2011). ...
... Since BR results in approximately 28-35% greater energy expenditure compared to FR at similar running velocities (Conti, 2009;Rasica et al., 2020), it may be a particularly effective method for stimulating positive adaptations in athletic qualities that are dependent on cardiorespiratory capabilities (Uthoff et al., 2019), such as RSA (Bishop et al., 2011). However, while previous findings indicated that BR training can improve running economy (Ordway et al., 2016) and oxygen consumption (Terblanche et al., 2005), there are no empirical investigations as of yet on the effectiveness of BR training on RSA. ...
... In addition, readers should be cognisant that all previous training studies which utilised BR, implemented either steady-state low-velocity running (Ordway et al., 2016;Terblanche et al., 2005) or maximal effort BR sprinting with work-to-rest ratios>1:3 (Terblanche & Venter, 2009;Uthoff et al., 2020). Furthermore, only the study by Uthoff and colleagues (Uthoff et al., 2020) explored the effects of BR training on speed and power measures in adolescent male athletes (age = 14.59 ± 0.29), and no studies have explicitly investigated the effects of repeated BR training (RBRT) on physical fitness capabilities in youth male soccer players. ...
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... Despite the positive effects of using the V peak_BR for BR training prescription 8 , and although previous studies have demonstrated the positive effects of BR training on FR aerobic performance, strength, power of the lower limbs, sprint, and agility 4,8,12,13,14 , a study veri ed the correlation between V peak_BR and other performance variables. Considering the importance of V peak_BR for optimizing the prescription of BR training, it is important to demonstrate which performance variables best de ne the speci c demands that characterize BR. ...
... The results demonstrated that BR training was effective in improving agility performance in a test with change of direction; the BR training group showed a greater reduction (Δ%: 0.475 ± 0.362%) compared to the control group (Δ%: 0.086 ± 0.196%). The effect of BR training on agility can be explained by the fact that BR provides more proprioceptive elements for body control and awareness (balance)4,14 .For the 20-m sprint test, the present study found a very low correlation (r = -0.06) with the V peak_BR .Although no previous studies have correlated these variables, Uthoff et al.22 demonstrated that eight weeks of sprint BR training with intensities classi ed as slow, moderate, and fast (20-45, 50-75, and ≥ 95% of maximal effort, respectively), and velocities self-selected by the participants, resulted in improvements in 10-m and 20-m sprint performances in forty-three male adolescents (aged 13-15 years). ...
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... walking endurance, mobility, and balance factors. Clinical rehabilitation programs using forward, backward, sideways, and cross walking training on various surfaces are known to improve balance and kinematic gait parameters [6][7][8][9][10]. In neuro-rehabilitation, backward walking training (BWT) is an alternative method which has been recently applied for improving motor capacity. ...
... Backward walking, although using the same rhythm cycle, is not thought of as a simple reversal of forward walking since it requires much higher physiological, sensory and perceptual effort [11][12][13]. BWT has been reported to ameliorate balance, postural control, walking parameters, and motor function in studies on the healthy population [9,14], stroke patients [10] and the elderly [5] in the literature. Moreover, it may have biomechanical and physiological advantages over forward walking, further enhancing lower extremity muscle strength [15] and cardiopulmonary response [7]. ...
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... Backward walking is not merely a reversal movement of forward walking but has its own unique advantages as gait training (Wang et al. 2018). Since backward walking is more difficult and physically demanding than forward walking (Flynn et al. 1994;Terblanche et al. 2005), several studies have suggested that backward walking training may provide additional benefits for gait performance than forward walking training (Ordway et al. 2016;Uthoff et al. 2018;Wang et al. 2018). During backward walking, visual information does not provide the ground conditions of the walking direction, and the motor patterns are unfamiliar. ...
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... Though the effectiveness of BR training on measures of athletic performance has been explored since the mid-to-late 2000's (10,26), empirical evidence in this area is still limited, with only a handful of studies looking at the performance adaptations associated with this direction of running (9-11, 26, 27). Therefore, more research on this topic should be conducted to gain a better understanding of direction-specific adaptations associated with BR and FR on phase-specific CoD performance, jump types utilizing varying degrees of elastic contribution, and the physiological and neuromuscular responses underpinning aerobic adaptations. ...
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... can increase levels of cardiovascular fitness and produce changes in body composition. 34 Similarly, a meta-analysis demonstrated that physical training can be correlated to reduced CRP levels regardless of age or gender, and that greater improvements in CRP levels could be seen additionally when the BMI is reduced. 35 In contrast, Mouridsen et al. noted that there was a spike in highsensitivity CRP as an immediate response to exercise, however, the increase was moderate and not independently associated with coronary artery disease. ...
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This study was conducted at the University of Kentucky Biodynamics Laboratory in Lexington, KY and was partially supported by a grant from the Kentucky Chapter of the American Physical Therapy Association. Backward running (BR) is employed for conditioning and for rehabilitation in sports, orthopaedics, and neurology. Our purposes were to compare kinematics and training effects of BR to forward running (FR). Ten runners (6 males, 4 females, ages 20-34 years) were assigned to a backward running (BRG) or control (FRG) group. Subject isokinetic muscular torque production (IMTP) and biomechanics during FR and BR at 3.58 m/sec were studied at the beginning and after 8 weeks of training. Stance time was significantly shorter during BR. The peak vertical component of the ground reaction force (Fz) and Fz impulse were significantly less during BR. After training, knee extensor IMTP of the BRG increased significantly at 75 and 120 degrees /sec. We concluded that BR produced lower Fz stress than FR and improved knee extensor torque at low speeds. Backward running may be clinically useful for reducing stress to injured joints and for increasing knee extensor strength. J Orthop Sports Phys Ther 1989;11(2):56-63.
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A meta-analysis was performed to assess the effects of type, duration and frequency of exercise training on changes in body mass (BM), fat mass (FM), fat-free mass (FFM) and percent body fat (percent fat) both for adult males and females. Weight loss following aerobic type exercise training, though modest, was greater for males. Stepwise regression suggests that, both for males and females, energy expended during exercise and initial body fat levels (or body mass) account for most of the variance associated with changes in BM, FM and percent fat associated with aerobic-type exercise training. In females, weeks of training and duration of exercise per session were also significant predictors. These findings confirm earlier research in males concerning exercise training effects on body mass and body composition and extend them both to females and to a broader range of exercise types. Of particular interest in this regard is the finding that weight training exercise which is similar to aerobic exercise in facilitating body fat loss, can also preserve or increase fat-free mass.
Article
The purpose of this study was to measure lower extremity joint moments of force and joint muscle powers used to perform backward running. Ten trials of high speed (100 Hz) sagittal plane film records and ground reaction force data (1000 Hz) describing backward running were obtained from each of five male runners. Fifteen trials of forward running data were obtained from one of these subjects. Inverse dynamics were performed on these data to obtain the joint moments and powers, which were normalized to body mass to make between-subject comparisons. Backward running hip moment and power patterns were similar in magnitude and opposite in direction to forward running curves and produced more positive work in stance. Functional roles of knee and ankle muscles were interchanged between backward and forward running. Knee extensors were the primary source of propulsion in backward running owing to greater moment and power output (peak moment = 3.60 N.m.kg-1; peak power = 12.40 W.kg-1) compared with the ankle (peak moment = 1.92 N.m.kg-1; peak power = 7.05 W.kg-1). The ankle plantarflexors were the primary shock absorbers, producing the greatest negative power (peak = -6.77 W.kg-1) during early stance. Forward running had greater ankle moment and power output for propulsion and greater knee negative power for impact attenuation. The large knee moment in backward running supported previous findings indicating that backward running training leads to increased knee extensor torque capabilities.
Article
1. Skinfold thicknesses at four sites – biceps, triceps, subscapular and supra-iliac – and total body density (by underwater weighing) were measured on 209 males and 272 females aged from 16 to 72 years. The fat content varied from 5 to 50% of body-weight in the men and from 10 to 61% in the women. 2. When the results were plotted it was found necessary to use the logarithm of skinfold measurements in order to achieve a linear relationship with body density. 3. Linear regression equations were calculated for the estimation of body density, and hence body fat, using single skinfolds and all possible sums of two or more skinfolds. Separate equations for the different age-groupings are given. A table is derived where percentage body fat can be read off corresponding to differing values for the total of the four standard skinfolds. This table is subdivided for sex and for age. 4. The possible reasons for the altered position of the regression lines with sex and age, and the validation of the use of body density measurements, are discussed.
Article
Backward walking has been advocated as a method of maintaining cardiovascular conditioning in patients undergoing knee rehabilitation because it may decrease patellofemoral joint compressive forces. The primary purpose of this study was to determine the relationship between the rate of oxygen consumption (VO2) and backward walking speed. Twenty-five healthy males, aged 18-35 years, participated in this study. The rate of oxygen consumption and heart rate were measured at the backward walking speeds of 0.89, 1.12, 1.34, 1.56, and 1.79 m/sec (2.0, 2.5, 3.0, 3.5, and 4.0 miles/hour, respectively). Analysis revealed a direct, curvilinear relationship between VO2 and backward walking speed. This research provides information that can be used to prescribe a backward walking rehabilitation program which may be appropriate to maintain aerobic fitness levels during rehabilitation of patients with patellofemoral pain syndrome.