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Journal of Exercise Physiologyonline

April 2015
Volume 18 Number 2

Official Research Journal of

Editor-in-Chief JEPonline
Tommy
the American
Boone, PhD,
Society
MBA of
Exercise
Review Physiologists
Board
Todd Astorino, PhD
The Effects of Combined Weight and Pneumatic
ISSN 1097-9751
Julien Baker, PhD Training to Enhance Power Endurance in Tennis
Steve Brock, PhD Players
Lance Dalleck, PhD
Eric Goulet, PhD
Robert Gotshall, PhD Suttikorn Apanukul, Sinlapachai Suwannathada, Chaninchai
Alexander Hutchison, PhD Intiraporn
M. Knight-Maloney, PhD
Len Kravitz, PhD Faculty of Sports Science, Chulalongkorn University, Bangkok,
James Laskin, PhD
Yit Aun Lim, PhD
Thailand
Lonnie Lowery, PhD
Derek Marks, PhD ABSTRACT
Cristine Mermier, PhD
Robert Robergs, PhD Apanukul S, Suwannathada S, Intiraporn C. The Effects of
Chantal Vella, PhD
Dale Wagner, PhD
Combined Weight and Pneumatic Training to Enhance Power
Frank Wyatt, PhD Endurance in Tennis Players. JEPonline 2015;18(2):8-16. The
Ben Zhou, PhD purpose of this study is to investigate whether a combined weight
and pneumatic training program provides better power endurance,
peak power, and agility adaptations than a free weight training
program alone. Thirty competitive male tennis players (mean age =
Official Research Journal 21.1 ± 0.1 yrs) were subjects in this study. All subjects randomly
of the American Society of assigned to 1 of 3 groups: (a) Combined weight and pneumatic
Exercise Physiologists training group (CB; n = 10); (b) weight training group (WT; n = 10);
and (c) control group (CO; n = 10). The subjects were tested for
ISSN 1097-9751 power endurance, peak power, and agility prior to the training, at
the 4th and after the 8th wk of training. Both the CB and the WT
groups performed identical training except that CB group used a
pneumatic resistance (via cable) attached to an Olympic barbell
loaded with plates; whereas, the WT group used just the Olympic
barbell loaded with plates. Statistical analyses revealed significant
(P<0.05) between-group differences after training. The results
showed that the CB group significantly increased power endurance
and peak power compared to the WT and the CO groups (P<0.05).
Hence, combined weight and pneumatic training is better than free
weight training alone for developing power endurance and peak
power.

Key Words: Combined Training, Weight Training, Pneumatic

Training, Power Endurance
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INTRODUCTION

Tennis is a power sport that is constantly and repeatedly requiring short explosive power bursts of
energy during the match. There are also quick changes of direction on the court that are produced
by the players’ strength (19,24). Hence, given the importance of power endurance, resistance
training has become an integral component of the elite athlete’s physical preparation to enhance
sports performance (28). The most common forms of resistance training are free weight training
(FWT), which uses gravitational force to oppose the force generated by muscles. However, FWT
has a drawback in the achievement of maximal effort due to the body’s lever systems. As an
example, when a subject begins to perform an arm curl exercise during FWT, the distance
between the barbell and the fulcrum (elbow) is the farthest. As a result, the resisting moment is at
maximum at this point and, therefore, the biceps brachii must generate enough force to be able to
lift the barbell. As the subject continues lifting the weight, the distance between the barbell and the
fulcrum continues to decrease (as does the resisting moment). This means that the force required
to perform the curl is reduced. This is termed the sticking region, which is the point in the
concentric phase of a near-maximal lift where the speed of the barbell slows to a minimal velocity
before accelerating again (9,10). Theoretically, if the sticking region is minimized, the force
generated by muscles to lift the barbell must be more uniformly distributed. This means that a
greater average muscle tension could be achieved throughout the range of movement and greater
strength gains should be achieved.

To compensate for the perceived drawback with FWT, pneumatic training (PT) was created where
by the resistance force is generated by air pressure. Hence, the inherent limitations of FWT may
be avoided by providing a load/resistance that is not subject to inertia (14). Consequently, the
forces generated should be more consistent during the entire concentric phase. Also, since the
resistant load in PT comes from air pressure, PT allows athletes to generate greater acceleration
and velocity due to its weightless resistant load. Forces generated during PT are more evenly
distributed over the athlete’s full range of motion than during FWT (12,14,18). Perhaps, this is why
several studies (4,6,21,23) indicate that PT is often used with older subjects and patients with
decreased lean muscle mass and with athletes who need muscular rehabilitation. However,
regardless of the consistent resistance at any training speed, PT is not without drawbacks.
Because of its weightless resistant load, PT cannot create the sticking region that is required to
train for power.

Recent reports (1,13,26) have demonstrated an increase in strength, velocity, and power
combination with FWT and other training techniques. But, they have not addressed the effects of a
combination specifically between FWT and PT. Such a combination would appear to allow for the
benefits of FWT and PT. After all, PT demands a greater amount of force generated over a longer
range of motion while FWT requires a greater amount of force during the beginning of a lift.
Combining FWT and PT allows the athlete to experience the sticking region during the beginning
of the lift due to the effects of FWT and greater resisting force due to PT at the end of the lift. To
the best of our knowledge, no studies have looked at combining FWT with PT. This paper attempts
to answer whether an FWT or a combination of FWT and PT is more effective in increasing power
endurance, peak power, and agility in tennis players during the sumo squats. We hypothesized
that a combined training between FWT and PT would significantly improve power endurance, peak
power, and agility when compared with FWT alone.
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METHODS
Subjects
Thirty male competitive tennis players (20.1 ± 0.1 yrs; weight, 72.6 ± 4.3 kg; height, 173.3 ± 3.2
cm) volunteered to participate in this study. The inclusion criteria were: (a) subjects must be
between 18 to 25 yrs of age; (b) subjects must be able to perform at least 1.5×bodyweight half
squat; and (c) subjects’ tennis proficiency must be better than 5.5 according to the USTA 1979
guideline. Exclusion criteria included no current musculoskeletal injuries or any other types of
injury. Prior to the commencement of the research, the subjects read and signed an informed
consent approved by the Ethics Review Committee for Research Involving Human Research
participants, Health Science Group, Chulalongkorn University, Thailand.

Procedures
Before training, the subjects attended a laboratory familiarization visit to introduce the testing and
training procedure used for the baseline measures. The subjects completed baseline tests for
power endurance, peak power, and agility. Then, they were randomly placed into 1 of 3 training
groups: CB (n = 10); WT (n = 10); and CO (n = 10). CB and WT completed training sessions 2
d·wk-1 for 8 wks. After 4 and 8 wks of training, mid- and post-training tests were conducted using
the protocol as the pre-training test.

Experimental Protocol
Power Endurance and Peak Power
Power endurance (PE) and Peak power (PP) were
performed using an FT 700 Power system (Fittech,
Australia), which was used as a force plate (400 Series,
Fittech, Adelaide, Australia) (Figure 1 A) and data collection
tool. The system was connected to a laptop (Figure 1 B)
installed with the Ballistic Measurement System software
(BMS, Innervations, Adelaide, Australia). The sampling
frequency was set at 200 Hz with sample period 40 sec in
length for PE and 10 sec in length for PP. The subjects
performed the standard warm-up and supervised warm-up
that included dynamic stretching. After the warm-up, the
subjects were asked to take a PP test that consisted of
performing 6 continuous and dynamic jump squats on a
force plate for 3 sets. There was a 3-min rest between sets
to ensure that the subjects had enough recovery to perform
the next set. The highest value of power of 18 squat jumps
(6x3) reported from BMS was recorded as the subjects’ peak Figure 1. The Experimental Setup
power. After finishing the PP test, the subjects had a 10-min for the Power Endurance and Peak
Power Test.
rest before performing 1 set of 30 continuous and dynamic
jump squats on a force plate for PE test (2). The average power of the 30 jumps was recorded as
the subjects’ power endurance. The subjects were instructed to jump with their maximum effort,
and verbal encouragement was given for both tests.

Agility
After finishing PE test, the subjects had a 30-min rest. The spider test (Figure 2) was used to
assess the specific agility (AG) performance for tennis players, in which 5 balls were placed on a
racket on the baseline at the center mark. The subjects were required to place the balls to the
indicated sideline or baseline as fast as possible. The subjects started at the center mark and ran
with the first ball to the sideline/baseline intersection and returned for the second ball. The subjects
 11

placed the second ball on the intersection of the service line and singles sideline, the third ball on
the intersection of the service line and center service line, the fourth ball on the intersection of the
opposite service line and single sideline, and the fifth ball on the intersection of the single sideline
and baseline (20). The subjects were required to perform 3 sets of the agility test with a 4-min rest
between sets. The minimum time (sec) of these values was kept.

Figure 2. The Spider Test (20).

Instrumentation
A Keiser-equipment power rack, equipped with pneumatic technology (Power Rack, Keiser,
Fresno, CA, USA) was used for the PT. Resistance, which was generated by an air compressor,
could be adjusted by the pedal at the bottom of the rack (Figure 3 A, C). An Olympic barbell was
attached to the rack by cables (Figure 3 A, D). The reported weight on the screen (Figure 3 A, E)
was the combined resistance from the barbell and pneumatic system.

Figure 3. A: Combined Weight and Pneumatic Training, B: Weight Training.

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Training Interventions
CB and WT were set to be equivalent in the intensity, which was 30% of 1RM in each subject
during training

Combined Weight and Pneumatic Training (CB): A proportion between weight and pneumatic
resistance was set at a weight resistance of 90%: pneumatic resistance 10% of 30% of 1RM. The
subjects were required to perform 3 sets of 20 repetitions of sumo squat.

Weight Training (WT): Similar to CB group, the participants in WT group were also required to
perform 3 sets of 20 repetitions of 30% of 1 RM of sumo squat. However in this group, the subjects
were instructed to lift a free weight resistance which was 100% of weight resistance.

A 4-min rest between sets was imposed on both the WT and the CB groups to ensure adequate
recovery of the phosphagen adenosine triphosphate (ATP) energy system (3,17). Moreover, the
subjects in both groups were instructed to lift the barbell with their maximum effort. Verbal
encouragement was given throughout their training. After training, both groups had a 1-hr rest
before performing skill tennis training.

Control Group (CO): The subjects were required to perform skill tennis training

Statistical Analyses

All statistical analyses were performed using SPSS statistical software for Windows (Version 17.0,
SPSS Inc., Chicago, IL, USA). Values are reported as mean ± SD. A 1-way ANOVA was used to
compare PE, PP and AG. For all testing conditions, the level of significance was set at P<0.05.

RESULTS

Table 1 and Figures 4 graphically displayed the results for each dependent variable obtained from
three conditions. The statistical analysis of power endurance showed that CB and WT were
significantly different than CO groups (P<0.05) after 4 and 8 wks of training. After 8 wks of training,
CB was significantly different than WT (P<0.05). With regard to peak power, CB and WT were
significantly different than CO groups (P<0.05) after 4 and 8 wks of training. After 8 wks of training,
CB was significantly different than WT (P<0.05). With regard to Agility, after 4 wks of training there
were no significant differences (P>0.05) and after 8 wks of training CB and WT were significantly
different than CO (P<0.05).

Table 1. Mean ± SD Values for Each Dependent Variable and Condition.

-1 -1
Power Endurance (W·kg ) Peak Power (W·kg ) Agility (sec)

Conditions
Pre-test Mid-test Post-test Pre-test Mid-test Post-test Pre-test Mid-test Post-test

Combined Weight
† †
and Pneumatic 51.29±2.47 56.47±1.90* 65.30±1.82* 64.83±3.89 71.85±6.14* 81.32±5.39* 17.39±0.60 16.81±0.56 16.11±0.68*
Training Group

Weight Training
53.02±5.41 57.21±5.13* 60.90±4.33* 64.59±4.98 71.51±5.31* 75.02±4.12* 17.81±0.75 17.32±0.70 16.45±0.37*
Group

Control Group 49.73±3.37 50.47±4.09 51.17±4.35 61.65±4.53 64.04±6.13 65.81±7.01 17.64±0.68 17.21±0.83 17.11±0.06

†
*Statistical difference from control group at P<0.05 Statistical difference from weight training group at P<0.05
 13

Figure 4. Average Change in Power Endurance, Peak Power and Agility after Training in Tennis
Players. Data are mean ± SD. CB = Combined weight and pneumatic training group, WT = weight training group and
#
CO = control group. *Statistical difference from control group at p<0.05 Statistical difference from weight training
group at P<0.05

DISCUSSION

The present study indicates that a combined weight and pneumatic training is an effective training
program to improve power endurance and peak power in tennis players. Combined training is
increasingly being used to enhance athletic ability and performance comparable to FWT
(1,10,13,16). The combination of free weight and pneumatic resistance merges the benefits of both
by allowing a greater amount of force to be generated over a longer range of motion.

A combined training of free weight and pneumatic improved peak power and power endurance
more so than FWT alone due to the imposition of pneumatic resistance at the eccentric phase at
sumo squat. In effect, then, the subjects developed stronger leg muscles (i.e., gluteus maximus,
quadriceps, hamstrings, and gastrocnemius), which are essential for power (7,25,27). Stronger
eccentric-related leg muscles allows the subjects to have a better transition from muscle extension
to a rapid contraction and/or explosive power (5,7,8,11,22).

As our testing procedure was similar to plyometric training, strong eccentric-related muscle was
required in order to achieve greater test results. A combined training between free weight and
pneumatic resistance training made muscles to work in both concentric and eccentric phase, while
FWT provided resistant force only in concentric phase. As a result, the subjects in CB had a better
peak power and power endurance than the participants in WT.

The results of the study illustrate that combined weight and pneumatic training significantly
increases hip and thigh power production (i.e., as measured by the dynamic jump squats) than
FWT alone. We believe that the combined weight and pneumatic training is highly effective in
enhancing muscular efficiency. This, in turn, allows for excellent transfer of power to other
biomechanically similar movement that requires a powerful thrust from the hip and thighs, such as
running.

CONCLUSIONS

The current research has demonstrated the effects of combined weight and pneumatic training on
power endurance of tennis players. The findings indicate that tennis players will benefit the most
when trained with combined weight and pneumatic training for power endurance training because
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it will increase power endurance, peak power, and capacity to avoid a decrease in velocity at the
end of longer sprint of the tennis players.

ACKNOWLEDGMENTS
The authors would like to thank participants of the study, The Chulalongkorn University Graduate
School Thesis Grant Fund and Faculty of Sports Science.

Address for correspondence: Chaninchai Intiraporn, PhD, Faculty of Sports Science,

Chulalongkorn University, Rama 1 Rd, Patumwan, Bangkok 10330, Thailand. Tel: +66 81 365
7351, Fax +66 2 218 1091. Email: c.intiraporn@yahoo.com

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