ArticlePDF Available

Abstract

International Journal of Exercise Science 17(1): 720-729, 2024. This study aimed to analyze the effect of box height on box jump performance among recreationally active college students. Fourteen males (age = 20.8 ± 4.1 years, height = 178.3 ± 6.3 cm, weight = 82.3 ± 13.0 kg) and seventeen females (age = 20.8 ± 2.1 years, height = 167.1 ± 5.5 cm, weight = 64.5 ± 7.4 kg) completed box jumps at five different box heights that corresponded to 0, 20, 40, 60, and 80% of their maximal box jump height. Variables of interest included peak force, rate of force development, peak rate of force development, peak power, velocity at peak power, jump height, time to takeoff , and reactive strength index modified. Peak force at 80% maximal box jump was significantly higher than 0% in the female cohort (p = 0.001). No significant differences for any of the other variables were observed in males, or at any other height lower than the 80% maximal box jump height for females (p > 0.05). Overall, variations in box height did not influence box jump performance in recreationally trained individuals when the intent to perform a maximal-effort jump was emphasized. This is important for strength and conditioning coaches and trainers, as they can utilize boxes of varied heights when teaching proper landing techniques to novice athletes with no decrements in propulsive performance.
Original Research
Does Box Height Matter? A Comparative Analysis of Box Height on Box Jump
Performance in Men and Women
MARCEL LOPES DOS SANTOS‡1, JOCAROL SHIELDS‡2, RICARDO BERTON‡3, TAYLOR
DINYER-MCNEELY‡4, MICHAEL TREVINO‡4, OLIVIA ANDERSON†4, and J. JAY DAWES‡4
1Biomechanics Laboratory, School of Kinesiology and Recreation, Illinois State University,
Normal, IL, USA; 2Department of Health Sciences, Stetson University, DeLand, FL, USA; 3School
of Physical Education and Sport, University of São Paulo, São Paulo, BRAZIL; 4School of
Kinesiology, Applied Health, and Recreation, Oklahoma State University, Stillwater, OK, USA
Denotes graduate student author, Denotes professional author
ABSTRACT
International Journal of Exercise Science 17(1): 720-729, 2024. This study aimed to analyze the effect of
box height on box jump performance among recreationally active college students. Fourteen males (age = 20.8 ± 4.1
years, height = 178.3 ± 6.3 cm, weight = 82.3 ± 13.0 kg) and seventeen females (age = 20.8 ± 2.1 years, height = 167.1
± 5.5 cm, weight = 64.5 ± 7.4 kg) completed box jumps at five different box heights that corresponded to 0, 20, 40,
60, and 80% of their maximal box jump height. Variables of interest included peak force, rate of force development,
peak rate of force development, peak power, velocity at peak power, jump height, time to take-off, and reactive
strength index modified. Peak force at 80% maximal box jump was significantly higher than 0% in the female cohort
(p = 0.001). No significant differences for any of the other variables were observed in males, or at any other height
lower than the 80% maximal box jump height for females (p > 0.05). Overall, variations in box height did not
influence box jump performance in recreationally trained individuals when the intent to perform a maximal-effort
jump was emphasized. This is important for strength and conditioning coaches and trainers, as they can utilize
boxes of varied heights when teaching proper landing techniques to novice athletes with no decrements in
propulsive performance.
KEY WORDS: Plyometric training, power, countermovement jump, jump training
INTRODUCTION
Plyometric training is commonly used as a method of improving lower-body power (16, 28).
Plyometric drills typically include bounding, hopping, and jumping movements. These
movements focus on a rapid stretch-shortening cycle (i.e., a rapid eccentric muscle action,
followed by a brief isometric phase and an immediate concentric muscle action) (7, 16).
Specifically, the ability to utilize the stretch-shortening cycle is pivotal to storing elastic energy
during eccentric muscle actions and then releasing it to produce forceful concentric contractions
(7, 16).
Int J Exerc Sci 17(1): 720-729, 2024
International Journal of Exercise Science http://www.intjexersci.co
721
Considerable debate exists amongst strength and conditioning coaches on the best ways to
prescribe certain plyometric drills (12, 16). The box jump is a plyometric drill widely used in
training programs but with limited scientific information about its prescription (11). When
performing a box jump, an individual is typically required to execute a countermovement jump
(CMJ) and propel the body up and forward and land with both feet onto a box (11, 26). Since
this drill can be performed using boxes of varying heights, it is important to determine the most
appropriate box height to elicit the greatest performance benefits. Koefoed et al. (14) investigated
the effect of two different box heights: low (70% of CMJ) and high (90% of highest achievable
box) on kinetic and kinematic variables. The authors reported no significant differences between
low and high box heights in peak force, peak power, rate of force development, concentric time
to take-off, and center of mass (COM) displacement. From these results, it can be assumed that
the ability to train at a higher box height may not produce greater performance benefits (14);
however, it is common practice for individuals to employ the highest available boxes that allow
for successful landing execution. Having a greater understanding of which box height allows
for maximal power development would be useful for both coaches and athletes seeking to
enhance performance.
From a fundamental biomechanical standpoint, there is no difference in take-off mechanics
when jumping to boxes of varying heights. However, when jumping to higher boxes,
individuals may be required to increase their hip range of motion in order to pull the knees high
enough to land both feet on top of the box. The adjustments in ankle, knee, and hip range of
motion required to successfully execute a horizontal displacement and land on higher boxes
may result in an increased risk of injuries (9). Furthermore, the inclusion of the horizontal
displacement in vertical jumps may affect the jump technique. Specifically, it may negatively
impact the jump concentric forces (19) as well as its eccentric kinematics during the propulsive
phase of the jump (20). Consequently, prolonged training with higher boxes may be detrimental
to sports performance as not achieving full hip extension during jumps may decrease torque
and power production, and thereby limiting training adaptations (19, 29). Considering these
factors, it might be advantageous to use boxes of low to moderate height during box jumps that
allow for full hip extension. Using low to moderate heights may be just as effective as using
higher boxes and could be safer than attempting higher jumps. This scenario holds relevance for
strength and conditioning coaches managing substantial cohorts, instructing novice athletes, or
operating with limited personnel and equipment. Another potential advantage of employing
boxes of low to moderate height resides in the propensity of individuals to land in the universal
athletic position, mirroring the biomechanical demands encountered in various sport-related
motions (6). Based on this similarity, the utilization of low to moderate box heights may hold
relevance in facilitating the learning of proper landing technique for novice athletes.
Despite these advantages, it is important to acknowledge a potential limitation pertaining to the
submaximal intention to achieve the box height. Specifically, low to moderate box heights may
inadvertently impose low motivation on individuals, resulting in the execution of box jumps
with submaximal effort. In turn, kinetic and kinematic variables, crucial to performance
enhancements, may be lower when employing low to moderate box heights compared to higher
Int J Exerc Sci 17(1): 720-729, 2024
International Journal of Exercise Science http://www.intjexersci.co
722
box heights. Regardless of this potential limitation, the performance of box jumps at varying
heights has not been investigated. Therefore, the goal of this study was to analyze the effect of
box height on box jump performance. The authors hypothesized that no significant differences
in kinetic or kinematic variables would be observed in when performing jumps at various box
heights in either sex, as long as maximal effort was provided.
METHODS
Participants
A convenience sample consisting of 14 males (age = 20.8 ± 4.1 years, height = 178.3 ± 6.3 cm,
weight = 82.3 ± 13.0 kg, BF% = 16.3 ± 7.4 %, CMJ = 42.1 ± 12.7 cm) and 17 females (age = 20.8 ±
2.1 years, height = 167.1 ± 5.5 cm, weight = 64.5 ± 7.4 kg, BF% = 28.0 ± 4.7 %, CMJ = 25.1 ± 6.3
cm) were used in this study. A minimum of 13 subjects for each group was deemed appropriate
based on an a priori power analysis using G*Power 3.1.9.7 (University of Düsseldorf, Düsseldorf,
Germany) with a large effect size (F = 0.4), statistical power of 0.95, and a type 1 alpha level of
0.05 (25). All individuals in this study were considered recreationally active based on their
current exercise habits (i.e., participated in ≥ 2.5 h of physical activities per week). The subjects
were also required to have had no lower-body injuries for the 6 months prior to participation in
the study. All subjects were informed of the risks and benefits of the investigation prior to
signing an informed consent and were allowed to withdraw from the study at any time without
penalty. This study was approved by the University Institutional Review Board for use of
human subjects (IRB 21-343-STW) with conformity to the Declaration of Helsinki (29) and the
ethical standards of the International Journal of Exercise Science (23).
Protocol
The study was completed in two testing sessions. In the first session, upon arrival to the lab, the
subjects had their height, body mass, and body composition collected. The subjects then
performed a standard dynamic warm-up and had their maximal box jump height assessed. The
warm-up consisted of performing 5 minutes of cycling on a Monark 828E cycle ergometer
(Monark, Vansbro, Sweden) followed by two sets of five submaximal CMJs onto 6” (15.24 cm)
and 12” (30.48 cm) boxes (8). The maximal box jump height was then assessed and following a
short rest, the subjects were familiarized with the box jump heights that would be used in the
second part of the study. Within a rest period of 48-72 hours from the first session, the subjects
returned to the lab for the second testing session. During the second testing session, the subjects
executed box jumps in relative heights of 0, 20, 40, 60, and 80% of their maximal box jump height,
in a random order. To ensure the prevention of neuromuscular fatigue, the subjects were asked
to refrain from strenuous activities within 24 hours prior to each testing session.
Age, Height, Body Mass, and Body Composition: Age was self-reported by the subjects. The
subjects’ height (cm) was assessed using a portable stadiometer (Seca, Hamburg, Germany).
Body mass and body composition assessments were performed via InBody270 (InBodyUSA,
Cerritos, CA) using standard procedures (5).
Int J Exerc Sci 17(1): 720-729, 2024
International Journal of Exercise Science http://www.intjexersci.co
723
Maximal Box Jump Height: The maximal box jump height protocol took place after the
completion of the standardized dynamic and specific warm-up previously discussed. The
subjects initiated the test by performing a CMJ on a Just Jump (ProBotics Inc., Huntsville, AL)
electrical contact operated system. All the subjects were instructed to step on the mat and, when
ready, perform a maximal effort CMJ with an arm-swing. The arm-swing motion was used
because this is standard practice when performing the box jump (8). The subjects were also
instructed to drop downward to a self-selected depth when performing the countermovement
portion of the jump. The CMJ height indicated in the jump mat was used as a reference for the
maximal box jump height. Plyometric boxes that corresponded to their jump mat CMJ height
were placed in front of the subjects. Then, subjects were asked to perform a CMJ and land onto
the boxes. In case of a successful attempt, the box height was either considered the subjects’
maximal box jump height or small increments in box height were performed. Alternatively, in
case of unsuccessful attempts, small decrements in box height were performed and subjects
were asked to repeat the jump. The subjects were allowed 30 seconds of rest between trials and
all subjects had their maximal box jump height determined within three trials. The highest box
the subjects were able to execute a CMJ with proper form (26) and land on was used as the
reference for the relative box height intensities in the second session.
Box Jump Test: The box jump test took place in the second testing session. Upon arrival to the
lab, subjects performed the same standard and dynamic warm-ups from the maximal box jump
test (8). The subjects performed jumps at the five different relative box heights while standing
on two force platforms (PASCO scientific, Roseville, CA). All subjects were instructed to step on
the force platforms (one foot on each platform) and, when ready, to perform a box jump as high
as possible. A combination of plyometric boxes (Rogue Fitness, Columbus, OH) were used and
corresponded to approximately 0, 20, 40, 60, and 80% of the subjects’ individual maximal box
jump height. The boxes were placed 5 cm from the force plates on a heavy-duty non-slip flooring
mat that was placed strategically in front of the force plates to match their height (jumps at 0%
were performed directly on the mat). The relative box height order was randomized to prevent
bias. Each box jump began with the subject standing still in front of the boxes with arms resting
on the sides of the body. All jumps were executed upon the investigator’s command and the
subjects were reminded before every trial to jump as high as possible regardless of box height.
This was reinforced because of the principle of specificity of plyometric training (7, 16). Training
at maximal intensity closely replicates the neuromuscular demands of high intensity sport-
related actions, making the training more specific and transferable to performance (16). Only
trials with correct CMJ technique (i.e., the subjects had to use arm-swing motion and they were
not allowed to tuck their knees during the upward portion of jumps) were considered for further
analysis. For each relative height, the subjects executed three box jumps. Rest intervals of 30
seconds between jumps and one minute after each height were provided.
Data Collection and Processing: The subjects’ force-time data was collected via 2 portable
PASCO force platforms PS 2142 sampling at 1000 Hz connected to an interface UI-5000 (PASCO
scientific, Roseville, CA). Vertical ground reaction force (vGRF) from each force platform were
combined into a net value and initially analyzed through the PASCO Capstone v2.4.1.8 software
Int J Exerc Sci 17(1): 720-729, 2024
International Journal of Exercise Science http://www.intjexersci.co
724
(PASCO scientific, Roseville, CA). From the vGRF data, the subjects’ impulse, acceleration,
velocity, displacement, and power were calculated through a forward dynamics approach (4,
18). After the initial calculations, the variables of interest were calculated. These included peak
force (PF), peak power (PP), rate of force development (RFD), peak RFD (pRFD), time to take off
(TToff), jump height (JH), reactive strength index modified (RSImod), and velocity at peak
power (vPP). The PF and PP were calculated from the force and power data, respectively. The
RFD was calculated by dividing the change in force by the change in time during the CMJ
braking phase (13, 21, 27) and pRFD was calculated as the largest force increase in a set of two
consecutive data points of the force-time slope during the CMJ braking phase (14). The TToff
was calculated from the point at which vGRF fell below a value equal to 5 times the standard
deviation of body weight (i.e., onset of movement) (18, 24) to the point at which vGRF reached
a threshold of 5 times the standard deviation of the vGRF of the unloaded force plates taken
over 300 ms (i.e., take-off) (17, 18, 24). Jump height was calculated as COM velocity at take-off
squared divided by two times gravity (i.e., 9.81 m/sec2) (3, 4) and RSImod was calculated by
dividing JH by TToff (4, 27). Lastly, vPP was defined as the COM velocity value at the point of
PP. All calculations were analyzed by a customized Microsoft Excel spreadsheet (Microsoft
Corporation, Redmond, VA).
Statistical Analysis
An initial visual inspection of the data (boxplot) was conducted and z-scores distribution were
analyzed to detect the presence of outliers. Data normality was assessed via Shapiro-Wilk’s test
and Levene’s test was conducted to assess the homogeneity of variances. Reliability between
repetitions was determined using a 2-way mixed effects model intraclass correlation coefficients
(ICCs) for relative reliability and coefficients of variation (CV) for absolute reliability (10). The
ICC reliability values were considered poor (≤ 0.50), moderate (0.51-0.74), good (0.75-0.89), and
excellent (≥ 0.90) (15). The CV values were considered good (≤ 5%), moderate (5.1-10%) and poor
(> 10%) (1,8). A series of one-way repeated measures ANOVA tests were performed to examine
significant differences in the dependent variables across the range of relative heights for each
group (i.e., men and women). Follow-up analysis included Bonferroni post-hoc comparisons.
Greenhouse-Geisser values were reported if the assumption of sphericity was violated.
Confidence intervals (CIs) for mean differences were calculated for all pairwise comparisons at
a 95% confidence level. Data were reported as mean ± standard deviation and alpha was set at
p ≤ 0.05. All analyses were performed using IBM SPSS v.23 (IBM, New York, NY, USA).
RESULTS
No outliers were detected and data were normally distributed and presented similar variance.
Relative reliability of all variables for both sexes was good to excellent, except for pRFD and
RFD at 20% maximal box height in the female cohort, which presented a moderate ICC. Absolute
reliability was poor for pRFD and RFD and good to moderate for all the other variables. All
reliability data are depicted in Table 1. Descriptive data of box jump performance variables are
presented in Table 2. Peak force at 80% maximal box height was significantly higher from 0%
only in the female cohort (p = 0.001). No significant differences for any of the other performance
Int J Exerc Sci 17(1): 720-729, 2024
International Journal of Exercise Science http://www.intjexersci.co
725
variables were observed in males, or at any other height beyond the 80% maximal box height
for females (p > 0.05).
Table 1. Reliability (ICC (95% CI and % CV) of performance variables during box jumps.
Variable
Box Height (% of maximal)
0%
20%
40%
80%
ICC
(95%CI)
%CV
ICC
(95%CI)
%CV
ICC
(95%CI)
%CV
ICC
(95%CI)
%CV
ICC
(95%CI)
%CV
Males
PF
.99 (.98-
.99)
1.79
.99 (.97-
.99)
2.21
.99 (.97-
.99)
2.45
.99 (.97-
.99)
2.14
.99 (.97-
.99)
1.97
RFD
.97 (.92-
.99)
12.17
.96 (.91-
.99)
11.01
.90 (.77-
.97)
12.40
.96 (.84-
.98)
13.75
.93 (.84-
.98)
13.35
pRFD
.86 (.65-
.95)
19.70
.83 (.60-
.94)
19.43
.84 (.61-
.95)
23.15
.77 (.45-
.92)
16.05
.88 (.66-
.96)
15.77
PP
.99 (.98-
.99)
3.10
.99 (.98-
.99)
2.49
.99 (.98-
.99)
2.58
.99 (.99-
.99)
1.74
.99 (.98-
.99)
2.17
VelPP
.98 (.95-
.99)
2.15
.99 (.98-
.99)
1.38
.99 (.98-
.99)
1.36
.99 (.97-
.99)
1.56
.99 (.97-
.99)
1.59
JH
.99 (.96-
.99)
4.22
.99 (.99-
.99)
2.80
.99 (.98-
.99)
2.97
.99 (.98-
.99)
3.02
.99 (.97-
.99)
3.45
TToff
.91 (.77-
.97)
4.83
.94 (.85-
.98)
3.82
.93 (.82-
.98)
4.43
.96 (.91-
.99)
3.95
.93 (.83-
.98)
4.22
RSImod
.98 (.96-
.99)
6.40
.98 (.96-
.99)
5.22
.99 (.97-
.99)
5.07
.99 (.97-
.99)
5.19
.97 (.93-
.99)
6.37
Females
PF
.98 (.96-
.99)
2.65
.98 (.96-
.99)
2.07
.98 (.95-
.99)
2.56
.99 (.97-
.99)
2.03
.98 (.96-
.99)
2.25
RFD
.81 (.57-
.93)
21.15
.69 (.27-
.88)
2.23
.91 (.80-
.97)
15.65
.90 (.77-
.96)
17.00
.84 (.65-
.94)
2.13
pRFD
.86 (.68-
.95)
14.70
.71 (.37-
.88)
15.55
.76 (.46-
.91)
21.08
.83 (.62-
.93)
15.96
.83 (.63-
.93)
16.86
PP
.97 (.93-
.99)
3.63
.98 (.94-
.99)
2.85
.98 (.94-
.99)
3.01
.98 (.95-
.99)
2.61
.97 (.94-
.99)
2.93
VelPP
.97 (.94-
.99)
2.36
.95 (.89-
.98)
2.80
.99 (.97-
.99)
1.71
.98 (.95-
.99)
1.79
.98 (.95-
.99)
1.89
JH
.97 (.93-
.99)
5.16
.96 (.91-
.98)
5.42
.98 (.95-
.99)
4.25
.98 (.95-
.99)
3.95
.97 (.94-
.99)
4.15
TToff
.92 (.82-
.97)
5.60
.94 (.87-
.98)
4.41
.89 (.75-
.96)
4.16
.93 (.85-
.97)
5.22
.95 (.89-
.98)
5.09
RSImod
.96 (.90-
.98)
8.37
.92 (.83-
.97)
8.06
.96 (.90-
.98)
6.26
.96 (.91-
.98)
6.49
.97 (.94-
.99)
6.74
ICC: intraclass correlation coefficient; %CV: coefficient of variation; PF: peak force; RFD: rate of force
development; pRFD: peak rate of force development; PP: peak power; VelPP: velocity at peak power; JH: jump
height; TToff: time to take-off; RSImod: reactive strength index modified.
Table 2. Performance variables during box jumps.
Variable
Box Height (% of maximal)
0%
20%
40%
60%
80%
Males
Box Height
(cm)
13.3 ± 2.9
26.7 ± 5.9
40.0 ± 8.8
53.3 ± 11.8
PF (N)
2110.4 ± 383.9
2070.7 ±
358.2
2135.4 ±
355.8
2125.5 ±
327.8
2112.9 ± 34.2
RFD (N·s-1)
4413.4 ± 2695.0
4188.2 ±
1998.1
4267.0 ±
1795.6
4586.8 ±
218.5
4585.0 ±
195.1
pRFD (N·s-
1)
13082.3 ±
6721.6
12096.7 ±
6094.5
12725.2 ±
6963.3
1255.5 ±
6404.1
10869.0 ±
3943.7
PP (W)
5189.2 ± 133.4
5187.9 ±
125.2
5263.6 ±
1218.1
5177.4 ±
121.1
5209.9 ±
1221.5
VelPP (m·s-
1)
2.65 ± .34
2.67 ± .33
2.62 ± .31
2.60 ± .32
2.62 ± .30
JH (m)
.42 ± .12
.42 ± .11
.41 ± .11
.41 ± .11
.41 ± .10
TToff (s)
.94 ± .13
.90 ± .12
.88 ± .13
.90 ± .12
.87 ± .12
RSImod
.47 ± .18
.49 ± .18
.49 ± .19
.48 ± .18
.50 ± .18
Females
Box Height
(cm)
9.2 ± 1.1
18.4 ± 2.2
27.6 ± 3.4
36.9 ± 4.5
PF (N)
1462.9 ± 228.3
1452.0 ±
221.0
1454.3 ±
209.6
1487.1 ±
223.8
1514.3 ±
226.6*
RFD (N·s-1)
3054.6 ± 1339.4
3036.9 ±
1411.4
2820.9 ±
121.9
3115.1 ±
1516.6
3381.5 ±
1674.9
pRFD (N·s-
1)
9092.4 ± 3167.4
8094.1 ±
1917.4
9449.0 ±
3275.1
9196.1 ±
2986.3
8911.6 ±
3363.5
PP (W)
2861.1 ± 49.6
2846.1 ±
443.6
2838.3 ±
438.6
2933.9 ±
423.9
2978.2 ±
456.0
Int J Exerc Sci 17(1): 720-729, 2024
International Journal of Exercise Science http://www.intjexersci.co
726
VelPP (m·s-
1)
2.10 ± .26
2.09 ± .24
2.09 ± .24
2.13 ± .22
2.12 ± .21
JH (m)
.25 ± .06
.25 ± .06
.25 ± .06
.26 ± .06
.26 ± .05
TToff (s)
.89 ± .16
.91 ± .16
.90 ± .10
.89 ± .14
.88 ± .18
RSImod
.29 ± .10
.28 ± .08
.28 ± .07
.30 ± .08
.31 ± .12
PF: peak force; RFD: rate of force development; pRFD: peak rate of force development; PP: peak power; VelPP:
velocity at peak power; JH: jump height; TToff: time to take-off; RSImod: reactive strength index modified.
* Significantly different from 0%
DISCUSSION
This study aimed to identify the effect of box height on box jump performance in recreationally
trained males and females. As expected, no significant differences in kinetic or kinematic
variables were observed in box jumps performed on boxes of varying heights in the male cohort.
However, PF at 80% maximal box height was significantly greater than PF at 0% with no other
significant differences in kinetic or kinematic variables for the female cohort. Consequently, the
authors’ original hypothesis was partially accepted. These findings suggest that the height of
the box does not affect the box jump performance in jumps that are executed at maximal effort.
Also, the observed significant difference in force output within the female cohort implies that
incorporating boxes in jump training could serve as a motivational tool for non-athletes to
perform jumps at maximal intended effort.
As mentioned, kinetic and kinematic variables were not affected by different box heights in the
male cohort (Table 2). To date, only Koefoed et al. (14) has investigated the effect of box height
on jump performance. However, these investigators only assessed two box heights and their
sample was comprised of elite female handball players. Nevertheless, the findings of the present
investigation align with this work. Koefoed et al. (14) did not observe significant differences
between high boxes for PF, PP, pRFD, concentric TToff, and COM displacement. In the present
study, no significant differences between the highest boxes (60 and 80% of maximal box height)
were observed in any of the measured variables (Table 2). Furthermore, it is the authors’ belief
that this study mxakes a novel contribution to the literature by examining and comparing low
and moderate box heights, and once again, no statistically significant differences were observed
across any of the variables (Table 2). The lack of significant differences between box heights in
the performance variables measured may be attributed to the maximal intention exerted during
the execution of each jump. As discussed, the subjects were consistently reminded to perform
the box jumps as high as possible regardless of box height. In this context, the primary and
hence, the most relevant factor appears to be the maximal intention to execute the box jump,
rather than the height of the box utilized, at least when utilizing boxes that are lower than the
subject’s peak CMJ.
Within the female cohort, no significant differences in 7 out of 8 assessed variables were
observed (Table 2). Only PF portrayed a significant difference between 0 and 80% maximal box
height (Table 2). At least for the highest boxes, the results of the current investigation are also in
Int J Exerc Sci 17(1): 720-729, 2024
International Journal of Exercise Science http://www.intjexersci.com
727
line with the findings of Koefoed et al. (14). These investigators did not observe any significant
differences in any kinetics and kinematics variables when comparing box jumps executed at 70%
of CMJ (low box) and 90% of maximal box jump height (high box). In the present study, no
significant differences were observed between the highest boxes (60-80% maximal box height)
for all variables (Table 2) in the female cohort. However, when comparing the highest (80%
maximal box height) with the lowest height (no box), a significant difference was observed for
PF, with no changes in PP or TToff. While the exact reason for this outcome remains unknown,
it could potentially be attributed to the implicit demand of overcoming a higher obstacle (11). In
other words, even though they were asked to jump with maximal intent (i.e., as high as possible)
in all box heights, the female subjects might have tried harder on the tallest box (80% CMJ).
However, it is worth noting that 80% maximal box height was not statistically different from
any of the other jumps in which the subjects had to land onto a box (20-60% maximal box height).
In this sense, it can be assumed that a minimal box height (i.e., 20% maximal box height) is
enough for individuals to perform box jumps with maximal intent. The lack of statistical
significance in performance measures across box heights can be seen as positive since the
mechanics needed to jump and land on higher boxes could potentially undermine the principle
of specificity and increase the risk of injuries, particularly among novice female athletes (9,22).
Nonetheless, it has been reported that female athletes can benefit from augmented feedback
when learning proper landing techniques and reduce the likelihood of injuries (22).
Furthermore, it has been reported that an athlete may be required to absorb a net force of up to
7 times their total body mass upon landing from a height of 40 cm (2). On the other hand, the
peak impact force is reduced by approximately 51% when using boxes that match the athletes’
maximal CMJ height (11). Therefore, jumping up to a box may reduce the overall level of stress
placed on the athlete, as the total load absorbed upon landing would be minimized due to the
height of the box. This is of particular significance for strength and conditioning coaches and
trainers, as the utilization of low to moderate boxes can facilitate the teaching of proper landing
techniques while allowing them to give augmented feedback to novice athletes and reduce the
likelihood of injury.
While this study makes a novel and significant contribution to the current literature, some
limitations should be acknowledged. First, the subjects in the present study were non-athletes.
Further research is needed to confirm whether similar results can be seen in athletic populations.
Second, the countermovement depth utilized by the subjects in this research was self-selected
during the box jumps. The non-standardization of countermovement depth may affect the push-
off phase and consequently, the kinetic and kinematic variables. Conversely, it is important to
note that the standardization of countermovement depth is uncommon and impractical within
the context of training, especially in large groups. Therefore, the investigators believe the
absence of this control increases the ecological validity of the present study. The subjects were
asked to perform an arm-swing prior to each jump, which may have affected the mechanics of
the jumps. However, as previously mentioned, the arm-swing is a fundamental part of box
jumps as it allows the subjects to coordinate the landing portion of the jump. Additionally,
although kinetic and kinematic changes due to box height may occur during the landing portion
of the box jumps, these were not explored in the current study. Further research is needed to
Int J Exerc Sci 17(1): 720-729, 2024
International Journal of Exercise Science http://www.intjexersci.com
728
investigate the effect of box height in kinematic and kinetic variables during the landing portion
of box jumps. Lastly, since this study employed a within-session design, it is unclear whether
the results would remain stable between training sessions. The inclusion of a between-session
analysis may confirm the results observed in the first testing session. Finally, only boxes up to
80% of the subjects’ maximal jump height were utilized in this research. It is unclear how
utilizing box heights at supramaximal levels (i.e., > than maximal CMJ height) affect
performance. It is the opinion of the investigators that this topic warrants further exploration.
This study showed that the box height, in general, does not affect propulsive performance in
recreationally trained males and females when performing the box jump with maximal effort.
When incorporating box jumps in a training program for less experienced individuals, it is
recommended to use box heights that are relative to their maximal box height. This is because
power and strength performance variables are not affected by box heights up to 80% of their
maximal height. Based on these findings, it is recommended the utilization of low to moderate
box heights (approximately 60% of maximal) when working with a population similar to that of
the present study. The rationale behind this recommendation is associated with facilitating a
secure landing onto a box, while also providing a stimulus to learning an appropriate landing
technique. Finally, strength and conditioning coaches and trainers should consistently
emphasize the importance of striving to achieve maximal jump height, regardless of the specific
box height being used.
REFERENCES
1. Banyard HG, Nosaka K, Haff GG. Reliability and validity of the loadvelocity relationship to predict the 1RM
back squat. J Strength Cond Res 31(7): 1897904, 2017.
2. Bobbert MF, Mackay M, Schinkelshoek D, Huijing PA, Van Ingen Schenau GJ. Biomechanical analysis of drop
and countermovement jumps. Eur J Appl Physiol 54(6): 56673, 1986.
3. Bosco C, Luhtanen P, Komi PV. A simple method for measurement of mechanical power in jumping. Eur J Appl
Physiol 50(2): 27382, 1983.
4. Chavda S, Bromley T, Jarvis P, Williams S, Bishop C, Turner AN, et al. Force-time characteristics of the
countermovement jump: Analyzing the curve in excel. Strength Cond J 40(2): 6777, 2018.
5. Collins KS, Christensen BK, Orr RM, Dulla JM, Dawes JJ, Lockie RG. Analysis of total and segmental body
composition relative to fitness performance measures in law enforcement recruits. Int J Exerc Sci 15(4): 24560, 2022.
6. Dawes J, National Strength & Conditioning Association (U.S.) (eds.). Developing agility and quickness. 2nd ed.
Champaign, IL: Human Kinetics; 2019.
7. De Villarreal ES-S, Kellis E, Kraemer WJ, Izquierdo M. Determining variables of plyometric training for
improving vertical jump height performance: A meta-analysis. J Strength Cond Res 23(2): 495506, 2009.
8. Dos Santos ML, Berton R, Shields J, Bishop C, Dinyer-McNeely T, Anderson O, et al. Influence of box height on
inter-limb asymmetry and box jump performance. Symmetry 15(7): 1359, 2023.
9. Hewett TE, Myer GD, Ford KR, Heidt RS, Colosimo AJ, McLean SG, et al. Biomechanical measures of
neuromuscular control and valgus loading of the knee predict anterior cruciate ligament injury risk in female
athletes: A prospective study. Am J Sports Med 33(4): 492501, 2005.
10. Hopkins WG. Measures of reliability in sports medicine and science. Sports Med 30(1): 115, 2000.
Int J Exerc Sci 17(1): 720-729, 2024
International Journal of Exercise Science http://www.intjexersci.com
729
11. Janikov MT, Pádecký J, Doguet V, Tufano JJ. Countermovement, hurdle, and box jumps: Data-driven exercise
selection. J Func Morphol Kines 8(2): 61, 2023.
12. Jarvis MM, Graham-Smith P, Comfort P. A methodological approach to quantifying plyometric intensity. J
Strength Cond Res 30(9): 252232, 2016.
13. Kibele A. Possibilities and limitations in the biomechanical analysis of countermovement jumps: A
methodological study. J Appl Biomech 14(1): 10517, 1998.
14. Koefoed N, Dam S, Kersting UG. Effect of box height on box jump performance in elite female handball
players. J Strength Cond Res 36(2): 50812, 2022.
15. Koo TK, Li MY. A guideline of selecting and reporting intraclass correlation coefficients for reliability
research. J Chiropr Med 15(2): 15563, 2016.
16. Markovic G, Mikulic P. Neuro-musculoskeletal and performance adaptations to lower-extremity plyometric
training. Sports Med 40(10): 85995, 2010.
17. McMahon J, Rej S, Comfort P. Sex differences in countermovement jump phase characteristics. Sports 5(1):
8, 2017.
18. McMahon JJ, Suchomel TJ, Lake JP, Comfort P. Understanding the key phases of the countermovement jump
force-time curve. Strength Cond J 40(4): 96106, 2018.
19. Meylan CMP, Nosaka K, Green J, Cronin JB. Temporal and kinetic analysis of unilateral jumping in the
vertical, horizontal, and lateral directions. J Sport Sci 28(5): 54554, 2010.
20. Meylan CMP, Nosaka K, Green JP, Cronin JB. Variability and influence of eccentric kinematics on unilateral
vertical, horizontal, and lateral countermovement jump performance. J Strength Cond Res 24(3): 8405, 2010.
21. Mizuguchi S, Sands WA, Wassinger CA, Lamont HS, Stone MH. A new approach to determining net impulse
and identification of its characteristics in countermovement jumping: Reliability and validity. Sport Biomech 14(2):
25872, 2015.
22. Myer GD, Stroube BW, DiCesare CA, Brent JL, Ford KR, Heidt RS, et al. Augmented feedback supports skill
transfer and reduces high-risk injury landing mechanics: a double-blind, randomized controlled laboratory study.
Am J Sports Med 41(3): 66977, 2013.
23. Navalta JW, Stone WJ, Lyons TS. Ethical issues relating to scientific discovery in exercise science. Int J Exerc
Sci 12(1): 18, 2019.
24. Owen NJ, Watkins J, Kilduff LP, Bevan HR, Bennett MA. Development of a criterion method to determine
peak mechanical power output in a countermovement jump. J Strength Cond Res 28(6): 15528, 2014.
25. Rhea MR. Determining the magnitude of treatment effects in strength training research through the use of
the effect size. J Strength Cond Res 18(4): 918-20, 2004.
26. Sands WA, Wurth JJ, Hewit JK. Basics of strength and conditioning manual. Colorado Springs, CO: National
Strength and Conditioning Association; 2012.
27. Suchomel TJ, Bailey CA, Sole CJ, Grazer JL, Beckham GK. Using reactive strength index-modified as an
explosive performance measurement tool in division I athletes. J Strength Cond Res 29(4): 899904, 2015.
28. Suchomel TJ, Nimphius S, Bellon CR, Stone MH. The importance of muscular strength: Training
considerations. Sports Med 48(4): 76585, 2018.
29. Van Lieshout KG, Anderson JG, Shelburne KB, Davidson BS. Intensity rankings of plyometric exercises using
joint power absorption. Clin Biomech 29(8): 91822, 2014.
... In terms of drop-height, it was suggested that youth athletes may be able to use SSC capabilities to increase vertical jump performance [12]. Specifically, the ability to utilize the SSC is pivotal to storing elastic energy during eccentric muscle actions and then releasing it to produce forceful concentric contractions [34]. In addition, greater leg muscle activities during preactivation appear to increase muscle stiffness by preparing agonist muscles to better resist high impact loads due to increased drop heights [8,11]. ...
Article
Full-text available
Background: Drop height has previously been used as an effective programming parameter in plyometric jump training. Less is known about the usage of maximal rebound jump height from a distinct drop height as a parameter for individualized plyometric jump training. Hence, the aim of this study was to contrast the effects of two different drop jump (DJ) training modalities using either the individualized maximal rebound height (MRHT) or a standard (SDHT) drop height on selected measures of physical fitness in young volleyball players. Methods: Thirty male young volleyball players aged 14 to 16 years were randomly assigned to an MRHT (n = 15) or an SDHT (n = 15) group. The MRHT group performed DJ exercises using a drop height according to the individual’s maximal rebound jump height from 30 cm, 40 cm, and 50 cm drop heights. The SDHT group performed DJs following a standardized drop height (30 cm) across the 8-week intervention period. The overall training volume was similar between MRHT and SDHT with one to three sets of 8 to 10 repetitions of DJ exercises per session. Before and after training, jump height and the reactive strength index (RSI) were taken as dependent variables from 30, 40, and 50 cm drop heights. In addition, dynamic balance (Y-balance test) as well as linear sprint and change-of-direction (CoD) speed were assessed. Results: Significant group × time interactions were found for jump height, balance, RSI, and linear sprint (p < 0.001; d = 0.12–3.42) but not CoD speed. Post hoc tests showed significant jump height improvements in favor of the MRHT group for drop heights from 30 cm (Δ20.4%, p < 0.001, d = 3.69), 40 cm (Δ20.3%, p < 0.001, d = 2.90), and 50 cm (Δ18.3%, p < 0.001, d = 3.37) and RSI50 (Δ30.14%, p < 0.001, d = 2.29). MRHT but not SDHT resulted in significant 5 m (Δ9.2%, p < 0.001, d = 1.32) and 20 m (Δ7.4%, p < 0.01, d = 2.30) linear sprint speed improvements. Conclusions: The findings demonstrate that MRHT but not SDHT improved DJ height, RSI, and linear sprint speed. Due to the importance of vertical jumps and short accelerations for overall competitive performance in volleyball, our results suggest that young male players should perform MRHT as part of plyometric jump training if the goal is to improve acceleration, reactive strength, and vertical jump performance.
Article
Full-text available
Box jumps are often included in training programs as an introductory exercise to novice athletes and untrained individuals and are an efficient option of lower-body explosiveness training. However, it is unclear whether the use of boxes of differing heights affect the inter-limb asymmetry during this exercise. The purpose of this study is to investigate the effect of box height in inter-limb asymmetry during box jumps. Recreationally active young males (n = 14) and females (n = 16) performed three jumps at boxes that corresponded to approximately 0, 20, 40, 60, and 80% of their individual countermovement jumps. The selected performance variables were peak force (PF), peak power (PP), rate of force development (RFD), and time to take-off (TToff). The intraclass correlation coefficients ranged from 0.76 to 0.99, and the coefficient of variation ranged from 4.03 to 16.52%. A series of one-way repeated measures ANOVA tests were used to test for significant differences of the performance variables and inter-limb asymmetries. The females’ PF at 80% was significantly higher from 0% (p < 0.05). No significant differences were observed for inter-limb asymmetry across box heights (p ≥ 0.25). This study shows that the box height does not affect the overall intra-session inter-limb asymmetries in recreationally active individuals.
Article
Full-text available
Apart from squat jumps, countermovement jumps (CMJ), and drop jumps, differences among other jump variations are not as well researched, making data-driven exercise selection difficult. To address this gap, this study compared selected concentric and eccentric jump parameters of maximal effort CMJ, hurdle jumps over 50 cm hurdle (HJ), and box jumps onto a 50 cm box (BJ). Twenty recreationally trained men (25.2 ± 3.5 years) performed 3 repetitions of CMJs, HJs, and BJs, each on separate days. The data were collected using force platforms and a linear position transducer. The mean of 3 trials of each jump variation was analyzed using repeated measures ANOVA and Cohen’s d. Countermovement depth was significantly greater (p ≤ 0.05) and peak horizontal force significantly lower during CMJ compared to HJ and BJ. However, there were no differences in peak velocity, peak vertical and resultant force, and total impulsion time. Finally, BJ significantly decreased peak impact force by ~51% compared to CMJ and HJ. Therefore, the propulsive parameters of HJ and BJ seem to be similar to CMJ, despite CMJ having a greater countermovement depth. Furthermore, overall training load can be decreased dramatically by using BJ, which reduced peak impact force by approximately half.
Article
Full-text available
This work aims to present concepts related to ethical issues in conducting and reporting scientific research in a clear and straightforward manner. Considerations around research design including authorship, sound research practices, non-discrimination in subject recruitment, objectivity, respect for intellectual property, and financial interests are detailed. Further, concepts relating to the conducting of research including the competency of the researcher, conflicts of interest, accurately representing data, and ethical practices in human and animal research are presented. Attention pertaining to the dissemination of research including plagiarism, duplicate submission, redundant publication, and figure manipulation is offered. Other considerations including responsible mentoring, respect for colleagues, and social responsibility are set forth. The International Journal of Exercise Science will now require a statement in all subsequent published manuscripts that the authors have complied with each of the ethics statements contained in this work.
Article
Full-text available
The countermovement jump (CMJ) test is commonly conducted to assess neuromuscular function and is being increasingly performed using force platforms. Comprehensive insight into athletes’ neuromuscular function can be gained through detailed analyses of force-time curves throughout specific phases of the CMJ, beyond jump height alone. Confusingly, however, many different terms and methods have been used to describe the different phases of the CMJ. This article describes how six key phases of the CMJ (weighing, unweighting, braking, propulsion, flight, and landing) can be derived from force-time records to facilitate researchers’ and practitioners’ understanding and application to their own practice.
Article
Full-text available
Increased popularity in the utilization of force plates to measure countermovement jumps (CMJS) for performance monitoring warrants the need for strength and conditioning coaches and sport scientists to better understand its force-time characteristics and the calculation of its associated variables. This article aims to provide information on how to understand and analyze the force-time curve of CMJS in microsoft excel, thus providing practitioners an inexpensive and accessible alternative to readily available software on the market.
Article
Full-text available
Banyard, HG, Nosaka, K, and Haff, GG. Reliability and validity of the load-velocity relationship to predict the 1RM back squat. J Strength Cond Res 31(7): 1897-1904, 2017-This study investigated the reliability and validity of the load-velocity relationship to predict the free-weight back squat one repetition maximum (1RM). Seventeen strength-trained males performed three 1RM assessments on 3 separate days. All repetitions were performed to full depth with maximal concentric effort. Predicted 1RMs were calculated by entering the mean concentric velocity of the 1RM (V1RM) into an individualized linear regression equation, which was derived from the load-velocity relationship of 3 (20, 40, 60% of 1RM), 4 (20, 40, 60, 80% of 1RM), or 5 (20, 40, 60, 80, 90% of 1RM) incremental warm-up sets. The actual 1RM (140.3 ± 27.2 kg) was very stable between 3 trials (ICC = 0.99; SEM = 2.9 kg; CV = 2.1%; ES = 0.11). Predicted 1RM from 5 warm-up sets up to and including 90% of 1RM was the most reliable (ICC = 0.92; SEM = 8.6 kg; CV = 5.7%; ES =-0.02) and valid (r = 0.93; SEE = 10.6 kg; CV = 7.4%; ES = 0.71) of the predicted 1RM methods. However, all predicted 1RMs were significantly different (p ≤ 0.05; ES = 0.71-1.04) from the actual 1RM. Individual variation for the actual 1RM was small between trials ranging from-5.6 to 4.8% compared with the most accurate predictive method up to 90% of 1RM, which was more variable (-5.5 to 27.8%). Importantly, the V1RM (0.24 ± 0.06 m·s⁻¹) was unreliable between trials (ICC = 0.42; SEM = 0.05 m·s⁻¹; CV = 22.5%; ES = 0.14). The load-velocity relationship for the full depth free-weight back squat showed moderate reliability and validity but could not accurately predict 1RM, which was stable between trials. Thus, the load-velocity relationship 1RM prediction method used in this study cannot accurately modify sessional training loads because of large V1RM variability.
Article
Full-text available
There is general agreement that the most valid method of measuring peak lower body power output (LBPP) in a countermovement jump (CMJ) is by analysis of the corresponding vertical component of the ground reaction force (VGRF)-time history of the jump. However, there is no published standard protocol. The purpose of this study was to establish a standard protocol. The variables necessary to define a valid and reliable CMJ method were: 1. vertical force range, 2. force sampling and integration frequency, 3. method of integration, 4. determination of body weight (BW) and 5. determination of the initiation of the CMJ. CMJs off a force platform (FP) were performed by fifteen male professional rugby players. The five variables were then optimised to maximise the reliability and validity of the measure of LBPP. Errors of less than 1% (p<0.05) in the measurement of LBPP were obtained using the following specification, 1. six times BW (using a 16-bit analogue to digital converter (ADC)), 2. 1000 Hz, 3. Simpson's rule or the trapezoidal rule, 4. mean VGRF for 1 second of quiet standing immediately prior to jump signal and 5. 30 ms before the instant BW ± 5 SD is exceeded after the jump signal. LBPP was most sensitive to variables 4 and 5. It was concluded that this study has established a standard protocol for the criterion method of measuring peak power in a CMJ using an FP. As all other estimates and less reliable methods of determining LBPP in a CMJ rely on the FP method for calibration, it is proposed that this protocol be used as the basis of future criterion measures using a FP.
Article
Law enforcement agencies often test the fitness performance and body composition of incoming recruits. This study investigated the relationships between whole and segmental body composition, and fitness tests in law enforcement recruits. A retrospective analysis of 72 male and 11 female recruits was performed. Bioelectrical impedance analysis (BIA) variables were: lean mass (LM), upper-extremity lean mass (UELM), trunk LM, lower-extremity lean mass (LELM), fat mass (FM), upper-extremity fat mass (UEFM), trunk FM, and lower-extremity fat mass (LEFM). Fitness tests included: vertical jump (VJ), peak anaerobic power (PAPw), 75-yard pursuit run (75PR), push-ups, sit-ups, 2-kg medicine ball throw (MBT), and the multi-stage fitness test (MSFT). Partial correlations and ANCOVAs between quartiles assessed relationships between body composition and performance. Significant moderate-to-large relationships were found; LM, UELM, trunk LM, LELM all related to PAPw (r = 0.500-0.558) and MBT (r = 0.494-0.526). FM, UEFM, trunk FM, LEFM all related to VJ (r = -0.481 to -0.493), 75PR (r = 0.533-0.557), push-ups (r = -0.484 to -0.503), sit-ups (r = -0.435 to -0.449), and MSFT (r = -0.371 to -0.423). The highest LM quartile (4) had superior PAPw and MBT than LM quartiles 1-3. Higher FM quartiles performed poorer in VJ, push-ups, and sit-ups. The 75PR quartiles 2, 3, and 4 were slower than quartile 1, and MSFT quartile 4 completed less shuttles. Total and segmental measures of LM and FM shared the same relationships; lower FM and higher LM related to better performance. Monitoring body composition could help guide training to optimize performance.
Article
Koefoed, N, Dam, S, and Kersting, UG. Effect of box height on box jump performance in elite female team handball players. J Strength Cond Res XX(X): 000-000, 2020-This study aimed at investigating whether a link exists between performance in a countermovement jump and the height of the box an athlete could successfully jump onto. Furthermore, it was investigated whether the height of the box influences the takeoff. Ten, elite, female team, handball players were recruited for the study (age: 20.9 ± 3.2 years; height: 174.7 ± 7.6 cm; mass: 73.8 ± 6.7 kg). Subjects performed 3 maximal countermovement jumps. Subsequently, subjects jumped onto boxes of increasing height until they could no longer successfully jump onto the box. Subjects then performed 3 box jumps with maximal intention to boxes corresponding to 70% of their maximal center of mass displacement (LOW) and 90% of their maximal achieved box height (HIGH). Finally, subjects completed another 3 maximal countermovement jumps. There was no relationship between the maximal center of mass displacement in countermovement jumps and the maximal achievable box jump height (r = 0.35; p = 0.071). Between jumps to LOW and HIGH boxes, there were no differences in the chosen variables, peak force (-156 ± 390 N; p = 0.239), peak power (25 ± 236 W; p = 0.747), peak center of mass displacement (0.003 ± 0.039 m; p = 0.840), peak rate of force development (-3.055 ± 6264 N·s; p = 0.157), and concentric time to takeoff (0.005 ± 0.044 seconds; p = 0.721). Because no differences could be found, the added risk of failure leading to injury and the limited possibilities of improving specific landing technique with low impact when jumping to high boxes in training cannot be justified.
Article
Objective: Intraclass correlation coefficient (ICC) is a widely used reliability index in test-retest, intrarater, and interrater reliability analyses. This article introduces the basic concept of ICC in the content of reliability analysis. Discussion for researchers: There are 10 forms of ICCs. Because each form involves distinct assumptions in their calculation and will lead to different interpretations, researchers should explicitly specify the ICC form they used in their calculation. A thorough review of the research design is needed in selecting the appropriate form of ICC to evaluate reliability. The best practice of reporting ICC should include software information, "model," "type," and "definition" selections. Discussion for readers: When coming across an article that includes ICC, readers should first check whether information about the ICC form has been reported and if an appropriate ICC form was used. Based on the 95% confident interval of the ICC estimate, values less than 0.5, between 0.5 and 0.75, between 0.75 and 0.9, and greater than 0.90 are indicative of poor, moderate, good, and excellent reliability, respectively. Conclusion: This article provides a practical guideline for clinical researchers to choose the correct form of ICC and suggests the best practice of reporting ICC parameters in scientific publications. This article also gives readers an appreciation for what to look for when coming across ICC while reading an article.