Healy and harrison et al. 2014 drop jump emg gluteo
Final VJ Report
1. The Effects of Dynamic and Ballistic Stretching with Differing Rest Intervals Prior to
Vertical Jump inDIII Male Football Players
Ashley Fox
Hope College, Holland MI
Spring 2015
2. Abstract
Stretching programs are often utilized in sports for injury prevention and to warm-up muscles
prior to competition. Varied stretching techniques exist (eg. static, dynamic, and ballistic);
however, controversy exists regarding which stretching technique will provide the greatest
benefit on subsequent vertical jump height. In addition, little is known regarding how the time
interval between stretching and jumping will affect performance. The purpose of this study was
to compare the effects of dynamic and ballistic stretching on vertical jump height with differing
rest intervals between stretch and vertical jump in DIII male football players. It was
hypothesized that dynamic stretching would increase vertical jump height to a greater degree
than ballistic stretching, and that vertical jump height would decrease as the length of the rest
interval between stretching and jumping increased. Ten DIII male football players aged between
19 and 22 were chosen to participate. After being familiarized with testing and stretching
procedures, each participant had his vertical jump height measured 0, 5, 15, and 30 min after
both ballistic and dynamic stretching. A minimum of 48 hours separated each testing session.
The stretching program and rest interval between stretch and jump were counterbalanced for
each participant to rule out any order effects. The data showed that dynamic stretching produced
significantly greater vertical jump scores when compared to ballistic stretching (-0.725±0.304;
p=0.041). There was no effect of time on vertical jump heights (-0.400 to 0.400± 0.258 to 0.587;
p=1.00) however, vertical jump heights were highest immediately after and 15 minutes after
participating in the stretching. It is therefore suggested that football players, prior to competing,
should warm-up using a dynamic stretching protocol in order to enhance their performance in
vertical jump height.
INTRODUCTION
Most athletes have a warm-up routine that they perform before competing. These warm- up
routines are important to reduce the athlete’s risk of injury (6). More often than not, there is
downtime for players between warm-up and when they go into competition. The proposed study
will examine the benefits of different stretching techniques, via vertical jump height, over
various time intervals between the warm-up and the actual performance to stimulate a game like
situation.
Ballistic stretching has not received a lot of attention when it comes examining its effect
on vertical jump height. A study that did look at effects of ballistic stretching by Kirmizigil, et al
3. (3) showed that vertical jump height increased immediately following ballistic stretching. In this
study the lumbar extensors, gluteus maximus, and hamstrings were stretched ballistically for 5
seconds each. To examine the effects of ballistic stretching on vertical jump height, a study
involving twenty males and females was executed (4). These results showed no significant
difference when no stretching was compared with ballistic stretching (4). To further the research,
Bradley et al. (6) did a study on ballistic stretching and its effects on vertical jump performance
over different time intervals. Eighteen male university students were the subjects in this study
and found that the vertical jump height decreased immediately after the 10 minutes of stretching
(hamstrings, quadriceps, and plantarflexor muscles), increased five minutes after stretching, but
then returned to control value after fifteen minutes had passed (6). These results show to be
inconsistent with the previously stated study. Due to the inconsistency in the findings for ballistic
stretching, further research is needed.
Dynamic stretching is another form of stretching that has also been studied recently, but
does not have much information regarding vertical jump height. In a study using female dancers,
dynamic stretching and a combination of both dynamic and static stretching showed an increase
in vertical jump height immediately after stretching gluts, quadriceps, hamstrings and calve
muscles for 60 seconds, when compared to static stretching (1). Another study looked at the
effects of secondary warm up following dynamic and static stretching on vertical jump height
immediately after the stretch and over different time intervals (5). Immediately after the dynamic
stretch and secondary warm up, the vertical jump height increased by 7.2% and then it decreased
gradually after 10, 20, 30, 45, and 60 minutes (5). A separate study done by Jaggers et al. (4)
found that dynamic stretching (focused on hip flexors, extensors, calves, glutes, and quadriceps,
4. performed five times slowly followed by ten times as quickly and powerfully as posible) did not
show a significant increase in vertical jump height when compared to a non-stretching. Again
these studies showed inconsistent results.
Due to the inconsistency of the results in dynamic stretching along with no studies being
done on the effect of the different time intervals in between dynamic stretching and performance
only incorporating a stretching program, further research is needed. No other previous studies
have looked at ballistic versus dynamic stretching effects on vertical jump height over differing
time intervals in DIII male football players either, therefore resulting this present study to be
necessary. DIII football players, specifically wide receivers, defensive backs, and linebackers
were chosen to be the subjects of this study because the results will be directly applicable to their
sport and specific position, and the results can be used and applied to improve their performance.
It is predicted that dynamic stretching when compared to ballistic, is expected to increase vertical
jump height to a greater degree when compared to ballistic based upon results of a study
focusing on the same muscle groups with a similar stretching tie (1,5). It is also thought that
vertical jump height will decrease over time when looking at both methods of stretching (6,5).
Purpose
The purpose of this study was to examine dynamic and ballistic stretching programs’ effect on
vertical jump height with differing time intervals of rest between stretch and vertical jump on
DIII wide receivers, defensive backs, and linebackers.
5. METHODS
Participants
A mix of ten Junior Varsity and Varsity wide receivers, defensive backs, and linebackers of a
football team from a private Division III college (ages 18-22) participated in this study. All
participants from the football team (Varsity and Junior Varsity) were contacted and recruited
through the head coach, which resulted with 10 players volunteering to participate. If the athlete
had a lower extremity injury, or consuming any illegal performance enhancing drugs they were
exempt from the study. Written informed consent forms approved by the Hope College ethics
board were obtained from all participants.
Study Design
This study was designed to examine the effects of two stretching techniques, dynamic and
ballistic on vertical jump height with differing times of rest intervals between stretching and
performance. All participants were familiarized with both stretching programs and techniques,
along with VJ, and aerobic warm-up procedures. Each day the players performed an aerobic
warm-up, followed by their randomly assigned stretching program. The stretching program and
rest interval between stretch and jump were counterbalanced for each participant to rule out any
order effects. The vertical jump (VJ) height was measured three times after their randomly
assigned rest interval. All testing was done prior to morning or afternoon workouts and
performed in Devos Fieldhouse. (Refer to Figure 1.)
6. Subjects: 10 Hope
College Football Players
Days 2-9:
Stretching
programs and rest
intervals were
counterbalanced
for all
participants.
Day 1: Familiarization,
Aerobic Warm-Up,VJ,
Stretching Programs
Dynamic
VJ after 30 min
Ballistic
VJ after 30 min
VJ after 0 min VJ after 0 min
VJ after 5 min
VJ after 15 min
VJ after 5 min
VJ after 15 min
Figure 1. Study design
Procedure
The first day of the study was used to familiarize the participants with the aerobic warm-
up, the dynamic and ballistic stretching techniques and programs, as well as the vertical jump
procedure. Visits two through nine consisted of each participant performing a vertical jump after
a randomly assigned stretching program and time interval. All of the time intervals (0, 5, 15, and
30 minutes) were counterbalanced among the participants along with their assigned stretching
7. program (Dynamic or Ballistic). During the assigned time interval of rest participants stood and
watch film of one of their high energy games from last season to stimulate a “sideline” like
feeling.
All stretching and vertical jumps took place in the DeVos Fieldhouse aerobic room. Both
Dynamic and Ballistic stretching programs targeted the four main muscle groups of the lower
extremities involved in performing maximum vertical jump. These muscle groups included the
quadriceps, hamstrings, calves, and gluteal muscles. Participants were asked to refrain from any
vigorous activity outside of normal team workouts 24 hours prior to testing.
Aerobic Warm-up Procedure
Each subject participated in an aerobic warm-up of a set distance. All participants ran together at
a moderate pace. This consisted of three laps around the main basketball court of DeVos
Fieldhouse and three down and backs (baseline to baseline of the basketball court). A 60 second
recovery period was allotted prior to stretching.
Dynamic Stretching Procedure
For the dynamic stretching program the participants performed four stretching exercises. Each
exercise was performed for 40 seconds (allowing 20 seconds for each side). The quadricep
muscles were stretched by having each participant begin in a wide stance, then kick their heels
back to the buttocks in an alternating fashion. The hamstrings were stretched by having each
participant walk forward kicking their legs to maximum height without sensation of tension
while the foot was dorsiflexed. To stretch the calves, the participants began in a downward dog
position and begin to perform a stationary jog making sure to drive their heels to the ground. For
8. the stretch targeting the gluteal muscles, the participants stood and pulled their knee to their chest
alternating legs, each knee was held to the chest for one second prior to switching sides.
Ballistic Stretching Procedure
For the ballistic stretching program the participants performed four stretching exercises. Each
exercise was performed for 20 seconds on the right side and then repeated for another 20 seconds
on the left side. To stretch the quadriceps muscles, the participant layed in a prone position with
their knee flexed. A theraband was wrapped around their foot and they held it with both hands
above their head. The participant then pulled on the theraband driving the heel of the foot closer
to the buttocks and then released. This was done in a “bounce” fashion where one bounce should
happen every second. The hamstring muscles were stretched by the participant standing feet
shoulder width apart followed by bending over to touch their toes. Again, this was done in a
bouncing fashion. Next, the participant assumed a one leg push-up position to stretch their
calves. They then drove the heel of their foot that is on the ground towards the floor and then
brought it back to neutral. The final stretch that the participants performed targeted the gluteal
muscles. To perform this stretch, the participant laid flat on their back with one knee flexed with
the opposite ankle resting on that knee. The head, shoulders, and back of the participants were
kept flat on the floor. Wrapping their hands behind and just above the knee they brought that
flexed knee towards their chest and bounced the stretch.
Vertical Jump Height Protocol
The Vertec was used to measure the participant’s vertical jump height. The participants started
with their feet together and their dominant side (the hand that they use to write with) closest to
the Vertec. The participants then reached their dominant arm as high as possible (this is where
9. the bottom vane of the Vertec was placed). The Vertec was then raised 12in if participant could
jump higher than top vane, this was added on to final measurement of the Vertec. The jump was
performed taking off from two feet without any extra steps taken before jumping. The participant
bent their knees to a comfortable angle and swung their arms back before jumping. While in the
air, the participant hit the highest vane possible. This was repeated three times, with a 30 second
rest interval between jumps, and the maximum height was recorded. The procedure for the VJ
followed the procedure outlined by Beam et. al (8), and is the same used in the NFL combine.
RESULTS
The average VJ height after each rest interval for both ballistic and dynamic stretching is
shown in Table 1. With the exception of after the 5 min rest interval, it can be seen that VJ
height averages after dynamic stretching with varying rest intervals were higher when compared
to the averages of VJ height after ballistic stretching. Dynamic stretching prior to jumping
resulted in a significant increase in vertical jump height compared to ballistic stretching when
data was pooled across all rest intervals (MD=.725*±.304; p=0.041). This can be seen in Table 2.
Stretching using either the ballistic or dynamic method showed no significant difference when
compared to no stretching prior to jumping (p>.05). As part of the familiarization phase of the
study each participant performed a baseline VJ after an aerobic warm up with no stretching
allowed prior to jumping. VJ height averages for both ballistic and dynamic stretching after
allotted rest intervals are compared to the average baseline VJ height in Table 3. Figure 2 shows
that dynamic stretching significantly increased VJ height when compared to ballistic stretching.
VJ height after ballistic stretching stayed close to the baseline VJ height. VJ heights were the
10. heights immediately (mean 30.4±0.792) and 15 minutes (30.1±0.706) after performing dynamic
stretching although these results were not significant. Each day participants were randomly
assigned a stretching program along with a random rest interval. The daily averages of each
vertical jump height are displayed in figure 3. This figure shows there was no order effect in
testing
Table 1. Means of VJ Height after Ballistic and Dynamic Stretching Along with Assigned
Rest Intervals
Type Timing Mean VJ (in) Std. Error
Ballistic
0 min 30.0 0.745
Ballistic
5 min 30.2 0.696
Ballistic
15 min 29.2 0.867
Ballistic
30 min 29.8 0.696
Dynamic
0 min 30.9 0.567
Dynamic
5 min 29.9 0.936
Dynamic
15 min 31.0 0.869
Dynamic
30 min 30.3 0.716
Table 2. Significance of Between Stretching Groups
(I) type (II) type
Mean
Difference (I-
II)
Std. Error Sig.
Ballistic Dynamic -.725* 0.304 0.041
Dynamic Ballistic .725* 0.304 0.041
Note*; *:significant, Std, Error: standard error, Sig.: p-value
11. Table 3. Average Vertical Jump Height Following Stretch and Rest interval
Time
Mean VJ
(in)
Std. Error
Baseline 30.0 0.803
B 0min 30.0 0.745
B 5 min 29.7 0.857
B 15 min 30.8 0.800
B 30 min 30.8 0.593
D 0 min 30.4 0.792
D 5 min 29.4 0.846
D 15 min 30.1 0.706
D 30min 30.1 0.836
Note* Baseline: vertical jump with no stretch, B: Ballistic, D:Dynamic
Figure 2. Mean vertical jump height at different rest intervals following dynamic or ballistic
stretching. Dynamic stretching produced a significantly higher vertical jump compared to
ballistic stretching (p=0.041). There was no effect of rest interval. Stretching programs did not
increase vertical jump compared to baseline.
12. Figure 3. Daily average for vertical jump height regardless of stretching program or rest interval.
No order effect present.
DISCUSSION
This study was designed to examine the effects of two stretching techniques, dynamic and
ballistic on vertical jump height with differing times of rest intervals between stretching and
performance. Each day the players performed an aerobic warm-up, followed by their randomly
assigned stretching program. The stretching program and rest interval between stretch and jump
were counterbalanced for each participant to rule out any order effects. Dynamic stretching prior
to jumping resulted in a significant increase in vertical jump height compared to ballistic
stretching when data was pooled across all rest intervals (p=0.041) consistent with some past
studies (1,5,6). However these finding contradict findings by Kirmizigil, et al (3), this may be
because in this study ballistic stretching was performed for only 5 seconds and in this study
13. stretching was performed for 20 seconds on each side, because the stretch was performed for a
longer amount of time in this study more micro tears in the muscles may have occurred resulting
in a less powerful contraction. There was no effect of the rest interval on vertical jump height,
even though results showed VJ height to increase immediately (Mean= 30.4±0.792) consistent
with past studies 1,5) and 15 minutes (Mean=30.1±0.706) after dynamic stretching when
compared to baseline VJ height (Mean=30.0± .803) the results were not significant. Neither
stretching program increased vertical jump significantly compared to no stretching (baseline),
which was consistent with past research (4).
Results suggest that a dynamic stretching protocol is more effective ballistic
at maximizing vertical jump height, athletes are encouraged to use a dynamic protocol prior to
competitions where they will be jumping (eg. football, volleyball, basketball, etc.). There are
some limitations to the study. The participant’s actions cannot be controlled outside of the study
(amount of sleep, attitude, effort, diet, social life etc.). There are some limitations that can be
associated with the vertical jump height test such as how much the participant bends their knees
and how much they swing their arms. Make up testing days sometimes had to be held less then
24 hours prior to the following scheduled testing day, which could have skewed individual
results due to muscle fatigue. As a group delayed muscle fatigue may have occurred from
conditioning days 48hours prior to testing skewing results preventing maximal power to be used
during VJ. Future studies may want to use force plates while measuring VJ to directly measure
the force and power produced to get more accurate results. Looking at different stretches effect
on power of the upper body would be beneficial for pitcher, batters, quarterbacks, and lacrosse
players.
14. References
1. Morrin N, Redding E. Acute effects of warm-up stretch protocols on balance, vertical jump
height, and range of motion in dancers. J Dance Med Sci. 2013;17(1):34-40.
2. Donti O, Tsolakis C, Bogdanis GC. Effects of baseline levels of flexibility and vertical jump
height ability of performance follwoing different volumes of state stretching and potentiating
exercises in elite gymnasts. J Sports Sci Med. 2014;13:105-113.
3. Kirmizigil B, Ozcaldiran B, Colakoglu M. Effects of three different stretching techniques on
vertical jumping performance. J Strength Cond Res. 2014; 28(5): 1263-1271.
4. Jaggers JR, Swank AM, Frost KL, Lee CD. The acute effects of dynamic and ballistic
stretching on vertical jump height, force, and power. J Strength Cond Res. 2008; 22(6):
1844-1849.
5. Pearce AJ, Kidgell DJ, Zois J, Carlson JS. Effects of secondary warm up following
stretching. Eur J Appl Physiol. 2009;105:175-183.
6. Bradley PS, Olsen PD, Portas MD. The effects of static, ballistic, and proprioceptive
neuromuscular facilitation stretching on vertical jump performance. J Strength Cond.
2007;21(1):223-226.
7. Brandenburg J, Pitney WA, Luebbers PE, Veera A, Czajka A. Time course of changes in
vertical-jumping ability after static stretching. J Sports Physiol Perform. 2007;2:170-181.
8. Adams GM, Beam WC. Exercise Physiology Laboratory Manual. 7th Edition. New York:
McGraw-Hill; c2014. 85-86.