Skip navigation

Tag Archives: vertical jump

De Villarreal et al have a really interesting study in the December issue of the Journal of Strength and Conditioning Research looking at the impact of different exercise protocols on the vertical jump. The authors studied college physical education students using one of five protocols: heavy full-squats, power half squats (i.e. to parallel), weighted counter-movement jumps (CMJ), plyometrics, and a combination of all. Subjects were tested on their vertical jump height and their performance on CMJs with 17kg, 27kg, and 37kg of added resistance.

All training took place 3 times per week for seven weeks:
• Heavy squat group: Gradually increased the resistance over seven weeks while decreasing the volume.
• Power half squat group: Gradually increased the resistance over seven weeks while decreasing the volume. The initial resistance was selected as the resistance that maximized power output, after the first week the resistance was increased each week and leveled out at weeks six and seven.
• Weighted CMJ group: Resistance was selected based upon what maximized power output. Initially the group exercised with 30% less than the amount that maximizes power output, over seven weeks this was increased.
• Plyometric group: sets of five rebound jumps.
• Combined group: Basically combined all the above workouts.

In terms of results:
• All groups increased the heights of their vertical jumps, the heights of their loaded CMJ height at each resistance, and the rate of force development during the loaded CMJs. There were no statistically significant differences between any of the groups.
• There were statistically significant increases in power output during loaded CMJs for the combined group and the weighted CMJ group only. However, all groups increased their power outputs by 3-13% at each resistance after seven weeks of training. So while this may not be statistically significant, it is an increase.

The results are interesting because essentially all the training programs worked. To me the most interesting result in the vertical jump height, the weighted CMJ testing condition isn’t really something that’s going to be duplicated on the field. The authors don’t give us the vertical jump values, only a graph so it is difficult to tease out the improvements in vertical jump. This suggests that heavy squats, squats done explosively, weighted vertical jumps, and plyos all improve vertical jump. The results are also interesting because the group with the greatest volume (the combined group) made the same gains as the other groups.

Now, there are some limitations. First, the subjects were college students. It’s very possible that strength trained athletes would have had different results. Second, the study may not have been long enough to tease out differences between the training programs. Third, all the squats and weighted CMJs are being done in a Smith machine which may impact both adaptations and transferability of the results. Finally, by using weights greater than that which maximized power output (the power squat group) or by using weights less than that which maximized power output (weighted CMJ group) both of these groups may not have made the gains that they could have as a result of the training.

De Villarreal, E.S.S., Izquierdo, M., and Gonzalez-Badillo, J.J. (2011). Enhancing jump performance after combined vs. maximal power, heavy-resistance, and plyometric training alone. Journal of Strength and Conditioning Research, 25(12), 3274-3281.

Advertisements

Andrews et al, in the September issue of the Journal of Strength and Conditioning Research, investigate complex training and whether the speed of the strength training exercise impacts the effectiveness of complex training. The idea being that by pairing a heavy strength training exercise with a plyometric exercise, the strength training will create something called “post activation potentiation (PAP)” which will enhance performance on the plyometric exercise. I have blogged about post activation potentiation and complex training (http://wp.me/pZf7K-3L) elsewhere because the results are pretty mixed on this. The reality is that the effectiveness of complex training may depend upon the type of plyometric being employed and on the level of the athlete.

The authors studied 19 Division I and II collegiate athletes with a mean back squat of almost 150% of bodyweight and a mean hang clean of more than bodyweight. The study was organized around having the subjects perform several sets of counter-movement jumps (CMJs), having them perform 3x3x75% back squats paired with CMJs, and having them perform 3x3x60% hang power cleans paired with CMJs (each in a pairing in a different session). The idea was to see which had the greatest impact on the height of the CMJs.

The results show that fatigue impacts vertical jumping height. After the first set of exercise, the athletes were only able to CMJ at 96-99% of their best CMJ. From the first set to the third, the CMJ-only group and the back squat complex group both lost about 4% of their CMJ height. In contrast, the hang clean complex group only lost .5% of their CMJ height from the first set to the third.

The results suggest that if the desire is to minimize the effects of fatigue on CMJ height during complex training, the hang clean (i.e. a fast strength training exercise) may be more effective than performing the CMJ alone or pairing it with the back squat.

There are a number of limitations with this study. First, the results may be population specific. Second, it’s possible that the resistance employed was insufficient to generate a PAP effect. Third, there is not a real smoking gun in this study demonstrating that any protocol is more effective at increasing CMJ height. It needs to be kept in mind that this study is looking at the acute response to narrowly defined training stimuli and does not demonstrate long-term adaptations from this type of training.

Andrews, T.R., Mackey, T., Inkrott, T.A., Murray, S.R., Clark, I.E., and Pettitt, R.W. (2011). Effect of hang cleans or squats paired with countermovement vertical jumps on vertical displacement. Journal of Strength and Conditioning Research, 25(9), 2448-2452.

Requena et al had a study published in the August Journal of Strength and Conditioning Research looking at the relationship between back squat strength, ballistic squat performance, vertical jump, and sprint speed.

The authors studied 21 “semiprofessiona;” sprinters (100 and 200 meter sprinters), though we are not given information about their performance on the 100 meter or 200 meter races.

It needs to be pointed out that the squat tests were unusual. Both traditional and ballistic squats were evaluated on a Smith machine. They were also tested having the subjects squat down to 100 degrees of knee flexion, hold it for two seconds, then perform the concentric phase of the lift.

Subjects were also tested on their vertical jump and 80 meters of sprints (with 10 meter splits recorded). These results were then correlated with the 1-RM on the traditional squat as well as maximal peak and average power on both squat tests.

The results are interesting:
• The vertical jump correlated with power values of the ballistic squat but not the 1-RM traditional back squat.
• Power outputs from the ballistic squat were more highly correlated with vertical jump performance than the traditional squat.
• The sprint times correlated with the 1-RM on the traditional squat as well as the power values for both kinds of squats.
• There was a trend for the ballistic squat power outputs to be more strongly correlated with sprint times than traditional squats.

The study is interesting from several standpoints. First, it is using a homogenous group of sprinters. This is both an advantage and a concern. An advantage because the results are very relevant to this population, a concern because the application of the results may be restricted to this population. Second, the relationship (or lack thereof) between vertical jump performance and 1-RM is counter-intuitive. This is something that warrants further study. Third, the trend for ballistic squat performance and vertical jump/sprint performance is interesting and warrants further study. Is this something that would apply more to one group of athletes or one level of ability rather than others?

Requena, B., Garcia, I., Requena, F., de Villarreal, E.S-S., and Cronin, J.B. (2011). Relationship between traditional and ballistic squat exercise with vertical jumping and maximal sprinting. Journal of Strength and Conditioning Research, 25(8), 2193-2204.

Argus et al had a study published in the August Journal of Strength and Conditioning Research looking at the impact of assisted, resisted, and bodyweight vertical jump training on vertical jump height.

The study involved two parts. In the first part, recreational weight trainers performed jumps on a force plate under resisted, assisted, and bodyweight conditions. Resisted involved performing jumps with elastic bands attached from the subject’s waist to the floor (i.e. resistance on the concentric phase of the jump). Assisted involved elastic bands attached from the subject’s waist to the ceiling (helps the subject during the concentric part of the jump). Bodyweight was a normal jump without any kind of assistance or resistance.

This part of the study found that the assisted jumps had the greatest peak vertical velocity and peak power, followed by free jumps, followed by resisted jumps. Peak force was greatest for resisted, followed by bodyweight, followed by assisted jumps.

The second part of the study involved four weeks of contrast training with rugby players. Twice a week they performed a set of four power cleans followed by six jumps under one of the three conditions. At the end of four weeks, the assisted group increased their jump height by almost 7%; the resisted group by almost 5%, the bodyweight group by almost 1.5%.

This is an interesting study because there are diminishing returns with exercise. As we become stronger it becomes more difficult to increase strength. As we become a more advanced athlete, it becomes more difficult to increase power. This study suggests some simple ways to make plyometrics more effective as athletes advance in fitness.

Argus, C.K., Gill, N.D., Keough, J.W.L., Blazevich, A.J., and Hopkins, W.G. (2011). Kinetic and training comparisons between assisted, resisted, and free countermovement jumps. Journal of Strength and Conditioning Research, 25(8), 2219-2227.

Moir et al had a study published in the June issue of Strength and Conditioning Journal essentially looking at post activation potentiation (PAP) and female volleyball players. The idea behind PAP is that a maximal force activity (like a really heavy squat) can produce a short-term increase in power. There are a lot of theories for why this could occur, everything from cueing the nervous system to making the muscle fibers more sensitive to calcium. In practice, this might involve performing a back squat at 90% of 1-RM for 2-3 reps followed by a set of counter-movement jumps (back in the day these approaches were called complexes).

PAP is one of those things that sounds really good. The challenge is that the research is extremely mixed as to its effectiveness. It appears that this is more effective with stronger athletes than with untrained subjects. It also appears that this is very task-specific, being present on certain types of explosive activities but not on others.

Moir et al investigated eleven division II female volleyball players. The athletes performed three familiarization counter-movement jumps in a session, were tested on their 1-RM on the back squat in another session, then in subsequent sessions performed each of the following protocols (all separated by several days):
• High Load (HL): Back Squat 2×50%, 1×70%, 3×90% followed by 2 minutes rest, then 10 counter-movement jumps (1 jump every 2 minutes).
• High Volume (HV): Back Squat 12×37% followed by the same jumping protocol as in the HL condition.

Results:
• On average, the subjects’ 1-RM on the squat was 143% of bodyweight.
• The HL protocol increased their knee flexion angles during the CMJ’s by 16%, in the HV protocol the athletes increased their knee flexion angles during the CMJ’s by 22%.
• When looking at the group means, the HL protocol did not increase jump height, the HV protocol actually reduced their jump height by 4%. Now, in the text the authors note that in the HL protocol 45% of the subjects actually increased their jump height with 18% having a decline in performance.
• The HL group increased their vertical stiffness by 16%, the HV group increased their vertical stiffness by 4%.

This study has mixed results with interesting implications. First, the protocol had no effect on jump height. However, the HL protocol significantly improved vertical stiffness. It is very likely that there was no improvement in jump height because the counter-movement jump is not one that requires a great deal of stiffness from the lower extremities. Had the researchers used a drop jump instead, the HL protocol may have had a positive effect on jump height.

This brings an important point about PAP and its research. It’s very likely that PAP, if it exists, has a positive effect on very specific types of performance – namely those involving a need for leg stiffness. This would include the jumps in track and field events, landings, agility, and sprinting (though research on this is mixed at best). It probably doesn’t improve performance in tasks that don’t require that leg stiffness (for example, a jump shot in basketball which would be similar to a counter-movement jump).

There are no magic bullets in terms of exercise. In other words there is no special drill, exercise, or training protocol that will magically improve someone’s performance. So PAP and other approaches to training need to be kept in perspective.

Having said that, even if it doesn’t enhance explosiveness PAP (or complexes as I learned them) would be extremely beneficial to an athlete who is in-season. This is due to the fact that when combining the training modes (heavy strength training plus explosive training), one is able to get more work done in a shorter period of time – which is really important when practice, competition, and travel have to be taken into account.

Moir, G.L., Mergy, D., Witmer, C.A., and Davis, S.E. (2011). The acute effects of manipulating volume and load of back squats on countermovement vertical jump performance. Journal of Strength and Conditioning Research, 25(6), 1486-1491.

Earp, et al. had an interesting article in the February issue of the Journal of Strength and Conditioning Research that reinforced something that I had written in an earlier post about plyometrics (http://wp.me/pZf7K-P) which is that different jumps may be applicable to different types of athletic events.  This is something that is really logical, but we rarely practice it with plyometrics.

The authors studied 25 “trained” individuals and looked at how characteristics like muscle fascicle length and pennation angle influences rate of force development on various jumps.  This is an interesting approach because there has been some work showing that pennation angle increases as a result of strength training and that length and angle both impact sprinting speed, but nothing looking at jumping.

Subjects performed 2-3 squat jumps (2 second pause at the bottom), countermovement jumps, and depth jumps (from a 30 cm box) on a force platform, the jumps were also videotaped.

There are some interesting results from this study:

  • Depth jump height > counter movement jump height > squat jump height, like you’d expect.
  • Peak vertical ground reaction force is greatest in depth jumps, then countermovement jumps, then squat jumps.
  • The depth jump had the greatest rate of force development at the 0-10, 10-30, and 30-50 millisecond time periods.
  • No anatomical variable predicted propulsion time for any jump type.
  • For the squat jump a longer Achilles tendon meant a faster rate of force production at the later stages of the jump.
  • For the countermovement jump, gastrocnemius fascicle length predicted rate of force development at the early stages of the jump (i.e. greater fascicle length meant greater rate of force development).
  • There is an intensity-dependent effect of Achilles tendon length on early force production.  Restated, higher intensity jumps requiring a faster rate of force production are more dependent upon Achilles tendon length than lower intensity jumps requiring a slower rate of force development.
  • Length of the muscle fascicles and the Achilles tendon is probably more important because of the “stretch” in the stretch shortening cycle.  Greater length means more stretch which means the ability to store and recover more elastic energy, in theory.

 

Things we don’t know from this study:

  • The “trained” status basically refers to recreational weight training.  Some subjects were former football players.  This means that it is challenging to carry these results over to an athletic population, which means that the usefulness of these results is limited.
  • We do not know how experienced these subjects were with these jumps.  Subjects with more experience (i.e. elite athletes) may have performed very differently.
  • We do not know basic things about these subjects like fast twitch fiber percentage, fiber area, or strength levels.  These are critical variables to successful performance of the jumps and may have impacted the results.  It also limits the applicability of the results to a larger population.

 

Interesting things that we can determine from this study:

  • The different jump types have different rate of force development profiles, which makes them more or less applicable to different athletic events.  For example, an athletic event that requires a RFD over a 0-50 millisecond time period is going to benefit more from a depth jump, one that requires it over 200-300 milliseconds is going to benefit more from a squat jump.
  • Fascicle length and Achilles tendon length may be things to look at for athlete selection, but this requires a great deal more research.

 

Earp. J.E., Kraemer, W.J., Cormie, P., Volek, J.S., Maresh, C.M., Joseph, M., and Newton, R.U. “Influence of muscle-tendon unit structure on rate of force development during the squat, countermovement, and drop jumps.”  Journal of Strength and Conditioning Research, 25(2), 340-347.

Joel Smith et al had a really interesting study published in the January issue of the Journal of Strength and Conditioning Research looking at depth jumps. They had noticed that the use of a goal (or target) in conjunction with depth jumps increases the height of the jumps and the knee flexor moments. Based on this, their study was meant to determine the differences between a regular depth jump from a 45-cm box, a depth jump from a 45-cm box with an overhead goal, and a depth jump from a 45-cm box over a hurdle.

The hurdle height was set to be individualized and challenging for each athlete. The athletes, prior to the test, determined the highest hurdle they could jump over using a counter-movement jump. For the testing conditions, the hurdles were set to be 5cm lower than that height.

The Vertec was used in a way that when the subjects landed from the depth jump, they attempted to jump as high as possible with that height being recorded by the Vertec.

The authors used Division III male athletes and after a standardized warm-up had them perform 12 depth jumps, four on each condition. The results are interesting:
• Ground contact time: The depth jump hurdle had an almost 25% shorter ground contact time than the other two jumping conditions.
• Vertical velocity at toe off: The regular depth jump had the lowest vertical velocity, the hurdle condition the highest, and the goal jumping condition was in-between. Remember that having a lower velocity is a bad thing in athletics.
• Joint kinematics: In terms of statistically significant results; the hurdle condition resulted in lower knee flexion, knee extension, and hip flexion, and hip extension angles than the other jumping conditions. This has some implications because of how elastic energy works, the greater the joint angles before the jump the more likely some of that elastic energy is going to be dissipated.
• Ground reaction forces: Greater for the hurdle group by 16-17%.
• Moments/power output: Ankle and knee flexor moments were greater for the hurdle group, along with power generation and power absorption. The authors feel this is especially important as they point out that the ankle is the largest power absorber and generator in unilateral power production.

The interesting take-home part of this study is that the depth jump combined with the hurdle may be really valuable for athletes that are in sports that require a short ground contact time. There has been a lot of debate in the track and field literature over the years that a lot of standard exercises and plyometrics have a ground contact time that is too long to adequately transfer for track and field, many authors (the authors of this study as well) point out that short vs. longer contact times are fundamentally different motor skills. An athlete may excel at one but not the other.

This study does have limitations that the reader should be mindful of:
• There’s a skill component to performing depth jumps which could influence the outcome: Athletes with more or less skill will respond differently and may very well score differently than the ones in this study.
• There’s a strength component to performing depth jumps which could influence the outcome: Plyometrics seem to be more effective for stronger athletes, we do not know the strength levels of the athletes in this study.
• The subjects had some challenges with the Vertec jumps: Dropping off the box, rebounding, and jumping up to touch the Vertec takes some skill and this could have had an influence on the results of this group.

Smith, J.P., Kernozek, T.W., Kline, D.E., and Wright, G.A. (2011). “Kinematic and kinetic variations among three depth jump conditions in male NCAA Division III athletes.” Journal of Strength and Conditioning Research, 25(1), 94-102.

Juan Jose Gonzalez-Badillo and Mario C. Marques had a study published in the December issue of the Journal of Strength and Conditioning Research looking at the relationship between kinematic variables of jumping with vertical jumping height.

A lot of studies have looked at vertical jump, this study is interesting because of the population. The authors looked at 48 male track and field athletes (primarily jumpers and sprinters) of whom 25 were international athletes.

In this study, the athletes performed a counter-movement vertical jump in a Smith machine. The athlete held the empty barbell on the back of their shoulders and then did the vertical jump. They did three jumps on a force platform.

They divided the jump into three phases:
• Eccentric phase: beginning of the jump until maximum negative velocity occurred
• Transition phase: the moment after maximum negative velocity until velocity of the center of mass reaches 0 meters/second
• Concentric: End of the eccentric phase until maximal positive velocity was achieved

They ran correlations between a number of variables and jump height for each jump. The correlations between all of the variables are statistically significant and include time spent in the eccentric/concentric phases, impulse of eccentric/concentric/transition, force in all three phases, peak power in all three phases, average power in all three phases, and maximum negative velocity.

The majority of these correlations, while statistically significant, are very weak. For example, eccentric time explains between 8 and 11% of the variation in jump height.

Several of the variables explain almost 50% of the variation in jump height, these include:
• Force production in each phase
• Concentric peak power
• Concentric average power
• Maximum negative velocity

These variables have some important implications for a strength and conditioning professional. First, force production indicates the need to have a strong lower body to be a better jumper. Second, the relationship of concentric power indicates the importance of explosive training to be a better jumper. The negative velocity shows how a fast stretch can help result in the storage of elastic energy, resulting in a higher jump. This also indicates the importance of plyometrics and the Olympic lifts in the training of jumpers.

Gonzalez-Badillo, J.J. and Marques, M.C. (2010). “Relationship between kinematic factors and countermovement jump height in trained track and field athletes.” Journal of Strength and Conditioning Research, 24(12): 3443-3447.