© National Strength and Conditioning Association
Volume 27, Number 4, pages 50–55
Weightlifting
Exercises Enhance Athletic Performance
That Requires
High-Load Speed Strength
Edith Cowan University,
Michael H. Stone, PhD Edith Cowan University,
United States Olympic Committee,
Summary
Weightlifting exercises can be effective for enhancing
athletic performance. This article provides a biomechanical and physiological discussion
as to why weightlifting exercises are useful to improve athletic performance
and how they may be integrated into a training program. Weightlifting is a sport in which athletes compete for the total weight
of 2 lifts: the snatch and the clean and jerk. The training methods used in
this sport are also used as a method of strength training for a wide range of
other sports. Weightlifting exercises can be effective for enhancing athletic
performance that requires high-load speed strength such as football,
basketball, volleyball, and track and field events because of their
biomechanical characteristics of high force and power output (11, 21).
Weightlifting exercises include the snatch, clean and jerk,
and variations of these such as the hang snatch, hang clean, snatch pull, and
clean pull. The purpose of this article is to provide a biomechanical and
physiological discussion as to why weightlifting exercises are useful to
improve athletic performance and how they should be performed in a training
program.
Why Are Weightlifting Exercises
Recommended?
Expression and Development of
Power
Power is the ability of the neuromuscular system to perform
work over a given time period or, alternatively, the product of force that can
be exerted at a given velocity of movement. For the majority of sports
performances, power output is the critical mechanical quantity required rather
than force production, that is, strength (17). As proposed by
In the process of diagnosing each athlete’s power qualities
and planning the training program, speed strength is classified into 2
qualities based on the load: high-load and low-load speed strength (16).
High-load speed strength is evaluated by power output with a relatively heavy
load (i.e., >30% of max), and low-load speed strength is referred to as power
output without external load or with a light external load (i.e., <30% of
max). To assess speed strength of the lower extremities, jump squat is often
used. Jump squat without load represents low-load speed strength, and jump
squat with a load of 55% of 1 repetition maximum (1RM), for example, indicates
high-load speed strength. Power output in jump squat with several different loads
(i.e., 30, 55, and 80% of 1RM) gives us a profile of speed strength (16).
However, relatively expensive equipment (e.g., position transducer or force
plate) is needed to measure power output in jump squat, and most athletes and
coaches do not have access to such equipment. When the equipment is not available,
the combination of the following measures may be useful to diagnose power
capacity for the lower extremities: 1RM squat for maximum strength, 1RM power
clean for high-load speed strength, and vertical jump for low-load speed
strength. If an athlete’s vertical jump height is good but 1RM power clean is
low, the athlete needs to improve high-load speed strength. If this is the
case, training for high-load speed strength such as using weightlifting exercises
should be considered.
Weightlifting Exercises Improve
High-Load Speed Strength
To enhance maximal power, athletes
need to perform training movements that involve rapid acceleration against
resistance, and this acceleration should extend throughout the movement with no
intention to decelerate at the end (19). Almost all rapid movements in sports
exhibit such an acceleration profile; therefore, the training method that
mimics this profile would likely induce desirable sport-specific adaptation.
During the pull phase of the clean and snatch and the drive phase of the jerk,
athletes extend their hips, knees, and ankle joints to push against the ground
as hard and as rapidly as possible at a given weight, producing just such an acceleration
profile for the barbell and body. The kinematics and kinetics are remarkably
similar to jumping (2, 8). Importantly, there is no need to control the upward
movement of the weight to
actively decelerate the barbell,
for this is achieved by the influence of gravity. In fact, athletes never
decelerate the upward movement in weightlifting exercises until extension is
complete. Thus, weightlifting exercises from a biomechanical evaluation are an
excellent method to train high-load speed strength.
In contrast, other types of strength-training exercises
intrinsically contain deceleration movements. Even if athletes try to keep
accelerating their movements, they are required to decelerate the weight at the
end of range of motion. Otherwise, the weight is released from their hands or
injury may occur to their musculoskeletal structures because of the kinetic
energy they must absorb (5, 19). In this manner, speed strength cannot be
improved efficiently.
Plyometric exercises such as
jumping, hopping, and bounding use the stretch shortening cycle and enhance
athletes’ power output in the concentric phase (1, 5). These types of exercises
have the same characteristic as weightlifting exercises in that they do not
require decelerating movements. Plyometric exercises
can be used to improve low-load speed strength but not high-load speed
strength. Because these exercises are performed with only the athletes’ own
body weight, or a relatively small weight such as a medicine ball, the load is
not high
enough to improve high-load speed
strength.
When an athlete performs a jump exercise with high load,
such as jump squats countermovement vertical jump with barbell or dumbbells),
the result is a very specific and effective exercise for developing high-load
speed strength (25). However, this exercise may cause injuries to the lower
leg, knee, back, and neck because of the high impact at landing (13). To
overcome this problem, several different electronic and mechanical systems have
been developed. Studies have reported that such systems enhance high-load speed
strength effectively while reducing the risk of injury (12, 13, 18). For example, Newton et al. (18) used a Smith machine
equipped with an electromagnetic braking system, which removed 75% of the
barbell weight during the eccentric phase of jump squats. They reported
significant improvement in vertical jump performance and the high-intensity
power training to be well tolerated. However, limited numbers of athletes have
access to such systems at this time because the systems are not in widespread
practical use.
Evidence to Support That
Weightlifting Exercises Improve Athletic Performance
Several studies have investigated the relationship between
weightlifting exercises and jump performance (2, 3, 8, 11, 21).
Canavan et al. (2) compared the movements of the hang
power snatch from above the knee to those of noncountermovement
(concentric only) vertical jump using collegiate athletes who were familiar
with these exercises. The authors reported similarities in maximal power, time
to maximal power, relative power, maximal force, and time to maximal force
between the hang power snatch and the vertical jump movements. Garhammer and
Gregor (8) showed that ground
reaction force in the snatch was similar to that of countermovement vertical
jump. The biomechanical similarities between the snatch and the vertical jump
help explain the findings from Stone et al. (21) and Carlock
et al. (3). Stone et al. (21) reported that the weightlifting exercises
improved vertical jump height and 1RM of snatch and clean significantly. Carlock et al. (3) also showed a strong correlation between
weightlifting performance and jump performance in weightlifters. Although these
studies are not definitive, they suggest that weightlifting exercises are
effective for improving jump performance. However, further research involving
long-term training interventions is required.
In our laboratory, one subject performed the hang power
clean and countermovement squat jump on a force plate. The kinematic
similarities in hip and knee extension can be observed during the hang power
clean (transition and second pull phase) and squat jump (ascending phase) from
Figures 1 and 2. In addition, upon examination of the vertical ground reaction
force, marked similarities were in both the magnitude and the shape of the
force time curve (Figure 3).
Few studies have addressed the effects of weightlifting
exercises on sprinting, stopping, changing direction, and throwing. Stone et al. (23) reported a strong correlation between
isometric clean pull and throwing performance (shot put and weight throw).
But, in general, few studies have investigated effects of weightlifting
training in comparison with other types of resistance training on athletic
performance. Hoffman et al. (11) compared weightlifting and powerlifting
in 20 college football players. One group participated in a program consisting
mainly of weightlifting exercises, and the other group participated in a
program consisting predominantly of powerlifting
exercises (squat, bench press, and deadlift). The authors found that the weightlifting group improved jump
performance significantly more than the powerlifting
group.However,
no significant difference was found between groups for improvement of sprint
and agility performance. This may be because all subjects participated in
sprint form drills, agility drills, and conditioning sessions in addition to
weightlifting or powerlifting exercises during the
last 5 weeks of their training periods.
As a research priority, biomechanical and physiological
studies are required to investigate the training effects of weightlifting
exercises on athletic performance other than jumping to address this gap in
scientific knowledge.
How Weightlifting Exercises
Are Introduced into a Training
Program
Equipment
As long as athletes perform with good technique and use
proper equipment, weightlifting exercises are as safe as or safer than other
sports and activities (22). The correct equipment, which includes bumper plates
and platforms, is desired in order to safely introduce weightlifting training.
This equipment allows athletes to drop barbells after they receive the weight
or whenever necessary. In addition, barbells themselves should have certain
levels of quality because the shafts need to rotate smoothly during the
receiving phase of the clean
and snatch. Otherwise, athletes may
injure their wrists, elbows, or shoulder when they receive the barbell. With a
set of barbells, plates, and platforms, athletes can perform a variety of
different exercises and train almost all muscle groups. Although a set of
weightlifting equipment can cost more than $1,000, purchasing weightlifting
equipment is much less expensive than purchasing several single-movement
machines, which is a further advantage of this training method. Also, as can be
seen in numerous examples around the world, weightlifting training can be
performed by large numbers of athletes simultaneously.
Techniques
Teaching proper exercise technique is one of the most
important tasks of strength coaches. It is readily apparent that beginners have
difficulty learning the techniques of the clean and snatch from floor. Because
the second pull phase exhibits higher force and power output than the first
pull (6, 7), it may be better for strength coaches to introduce the clean and
snatch from the hang position (or from boxes) so that the technique is
simplified and lifters still take advantage of the second pull phase. Newton
(15) recommended that athletes should learn the receiving position first and then
learn the second pull. Hedrick (10) has proposed 12 steps for teaching the
clean: education, modelling, foot
position, hand position, grip, start position, jump shrug, low pull, high pull,
clean, adjusting foot position, and squat clean. This teaching method can be
also applied for teaching the snatch. By following the 12 steps, athletes will
learn the second pull phase of the snatch and clean more easily.
To learn techniques of weightlifting exercises, athletes
should always use the weights that they can lift safely. At the beginning of
training, athletes may prefer to use a wooden pole or polyvinyl chloride pipe
and then a bar without weights. Eventually, athletes should add 10 to 20
lb to each set depending on their
skill progression. If the strength coach notices that an athlete does not
perform correct technique at any stage, he or she should have the athlete use
lighter weight until proper technique is achieved.
Strength coaches must monitor the exercise techniques of
their athletes during the training. Schilling et al. (20) have stated that if
athletes perform the clean and snatch with proper technique, their feet should
not be displaced forward but rather slightly backward. Chiu and Schilling (4)
have also described that the feet remain in the same vertical plane in
which they started the movement.
Therefore, strength coaches need to observe athletes’ feet displacement during
weightlifting exercises and give feedback immediately after every repetition
(rep).
Designing a Program
There are 5 variables to design a weight training workout:
exercises, loads, reps, sets, and rest periods. Strength coaches should
consider these variables carefully to meet the purpose of training. If the
purpose of training is to improve
high-load speed strength, weightlifting exercises are an excellent selection.
To train high-load speed strength
by using weightlifting exercises, athletes need to use the weight that
maximizes mechanical power output. Power is a product of force and velocity,
and there is an inverse relationship between the two (1, 5, 17). Therefore,
when athletes
use heavy weights, force output is high but velocity will be
low, and vice versa. Haff et al. (9) reported
that the clean pull at 80% of 1RM power clean produced higher power output than
that of 90% and 100%. Moore et al. (14) showed that the hang power clean at 70%
or lighter loads produced lower power output than that of 75% or higher loads.
These results may suggest that loading 75 to 80% of the athletes’ 1RM maximizes
power output during weightlifting exercises.
However, if athletes’ skill levels are inadequate, they
should focus on learning proper technique by using the weight that they can
lift safely. Further research is required about the effects of training experience
on the optimal load for power output in each of the lifts.
Theoretically, rep and load have an inverse relationship. If
an athlete needs to use a heavy weight, he or she cannot perform many reps. If an athlete needs to perform many reps, the load must be
relatively low. If an athlete needs to improve high-load
speed strength, he or she should perform all reps with high power output.If an
athlete’s power output becomes significantly low (=90% of initial value) during
the set because of fatigue, either the reps are too many or the loads are too heavy.
Typically, when competitive weightlifters or strength and power athletes
perform weightlifting exercises (snatch and clean), their number of reps per
set is 5 or fewer (1).
Athletes are generally recommended to perform 3 to 5 or 6
sets for each exercise (1, 5). Strength coaches should consider the influence
of fatigue if the aim of training is high-load speed strength. If athletes’
power outputs are significantly impaired at the fifth or sixth set because of
fatigue, it would not be effective to improve their high-load speed strength.
At present, no study has monitored the influence of fatigue on performance of
weightlifting exercises during consecutive sets. However, Wendell et al. (24)
monitored the change of performance
(mean velocity) of weighted jump squat training through 10
sets of 5 reps at 70% load of their 1RM squat and found that the performance
was significantly impaired by the sixth set. If the key point is to improve
high-load speed strength, athletes should perform every rep and set at as high
of a power output as possible. Therefore, athletes are suggested to take 2-,
3-, or even 5-minute rests between sets to maximize power output (1).
However, if the main focus of training is power output under
a fatigued condition (e.g., to improve blocking performance in football after
several consecutive drives), the rest period between sets is shortened. In this
condition, it may be necessary to reduce the load regarding
the fatigue level to minimize
decreases in power output. It is also important for strength coaches to
consider the selection of exercise such that exercises with relatively less
difficulty (e.g., clean pull from mid thigh) and not exercises that require
high skill (e.g., snatch from
floor) are preferable.
Conclusion
In this article we have presented a biomechanical rationale
as to why
weightlifting exercises are
effective for improving athletic performance that requires high-load speed
strength. When strength coaches include weightlifting exercises in training
programs, it may be better for them to introduce variations such as the hang
clean first so that they can simplify their teaching process and that athletes
can still take advantage of high velocity and high power output. If athletes have adequate levels of exercise technique, it
is suggested that they use
75 to 80% of 1RM load, with 5 or
fewer reps per set to improve high-load speed strength.
However, it is also evident that more research is necessary
to investigate the efficacy of weightlifting exercises in comparison with other
types of resistance training. More training studies are necessary to
investigate the effect of weightlifting exercise on athletic performance. .
Naruhiro Hori is a doctoral
student in Exercise, Biomedical and Health Sciences at
Robert U. Newton is the foundation professor in Exercise,
Biomedical and Health
Sciences at Edith Cowan University,
Kazunori Nosaka is an associate
professor in Exercise, Biomedical and Health Sciences at the
Michael H. Stone is the head of sports physiology for the
United States Olympic Committee. His service and research interests are
primarily concerned with physiological and performance
adaptations to strength and power
training. He is also an adjunct professor at Edith Cowan University, Perth,
Western Australia; Edinburgh University, Scotland; and at Louisiana State
University in Shreveport.
August 2005 • Strength and Conditioning Journal