The Best of This Month’s Strength & Conditioning Research: Time off from Training Spares Gains, Increased Athletic Performance with Contrast Movements and Variable Resistance Leads to Greater Strength and Power Gains.

I know, you mean to keep up with the latest research and read a few of the top journals every month.  You really do mean it but then work happens, and eating, and sleep, not to mention finding time to train.  Well don’t worry, I’ve got you covered here at FitnessBreakdown with a few quick summaries of some of the most interesting and applicable research being published.  That’s why you’re reading this blog anyway, it’s much easier to let us do the dirty work and sort through the hundreds of articles published every month to find the pieces of information that make a difference to your everyday work or training.  This week some highlights from the April 2017 issue of The Journal of Strength and Conditioning Research.

Short breaks in training do not lead to losses in strength and body composition

Hwang et al. (2017) examined the impact of a 2 week detraining period following a 4 week training period, with a second 4 week training period taking place after the break.  The authors were primarily interested in the impact on muscle strength and cross sectional area (hypertrophy) and how they differed through the training cycle.  Specifically how training gains in strength and mass occur at a greater rate in the early part of training and with a longer training period the gains occur at a slower rate.  The authors hypothesized that if subjects trained for four weeks with the faster rates of improvement and then took a 2 week training break that in the next 4 weeks they would experience the same faster gains that originally occurred as opposed to the slower rate of improvement that is seen with longer term training.  Essentially, does a train-rest-train approach allow for faster overall improvements as opposed to a longer term train-train-train approach?

The authors also used a group that was supplementing with 25g of whey protein post workout and a control group that used a carbohydrate supplement.  Over time they found increases in leg press strength after the training period, the detraining period and the retraining period. They did not note a significant difference between the different training periods or between the groups. There were no significant difference in body composition, lean mass, fat free mass or rectus femoris cross sectional area.  There was no evidence that a break in training resulted in faster gains when training is resumed.

While there were no earth shattering results from this study there was a key takeaway.  The two week detraining period did not result in any reduction in strength, muscle cross sectional area or lean mass.  This suggests that with well-trained individuals it is safe to take short breaks in training without worries about losing the improvements that were gained during the training period.  Many hard training individuals are afraid to take time off and allow their body a fuller recovery period and this study supports the benefit of regular short detraining periods, especially considering the small but positive improvements that happened during the detraining period.  Keep in mind this study used young males who were experienced in training and worked out four times per week.  The results may not hold true for older populations and those who train on a less regular basis or at lower intensities.  There is also a question of the length of detraining periods and the benefit sparing effect of a two week break on this population cannot be extrapolated too much longer detraining periods.


In-season strength training, especially with the addition of contrast movements improves athletic performance in youth soccer players

With the multitude of training approaches available it can become difficult for today’s strength coach to determine which philosophy to follow in order to maximize performance of their athletes.  This is further complicated by the different demands athletes face throughout the year in regard to what aspect of the training season they are in (preseason, in season, post season, off season). Hammami et al. (2017) attempted to partially answer this question in a study of in season junior male soccer players.  Specifically they were comparing the effect of pure resistance training program as opposed to a contrast strength program (and a control group) on a battery of athletic performance measurements.

The study lasted for 8 weeks and took place during a competitive season when the athletes were practicing 4-5 times per week and playing one competitive match.  The strength training group replaced a portion of their regular training time with program that consisted of back half squats to 90° utilizing weights that were 70-90% of their 1 rep maximum.  This program was performed twice per week.  The contrast strength training group performed the same squat program but for the first 4 weeks of the program, after every set of squats they performed 3 consecutive countermovement jumps with aimed arms.  During the second 4 weeks of the program the contrast strength group preformed 1 countermovement jump with aimed arms immediately followed by a 15-meter sprint.

Athletic performance was tested through 8 different measures that included 40-meter sprints, 4×5-m sprints, 9-3-6-3-9 meter sprints with 180° turns, 9-3-6-3-9 meter sprints with forward and backward running, repeated shuttle sprints, repeated change of direction, squat jumps and countermovement jumps.

In all measurements except the repeated shuttle sprint ability the strength training group and the contrast strength training group showed significant improvement as compared to the control group.  In the repeated change of direction test and the 4×5 meter sprints the contrast group showed significant improvement as compared to the standard strength group.  In all of the other tests both experimental groups showed similar improvements though with a non-statistically significant but still measured difference favoring the contrast training group.

So what is the take away?  First, an in-season strength program completed twice a week improved actual performance measures that should translate to increased advantages in competition.  Secondly, while both training approaches work well, the contrast training plan appears to have advantages and is easily implemented.  Third, the strength training programs both consisted of nothing more than squats or squats plus the contrast movements.  In today’s You Tube/Cross-Fit influenced training world of more volume, high intensity and creative mixes of movements a very simple, straight forward training plan improved performance.  The pressure on strength coaches to integrate these new influences in training programs is significant and perhaps in some cases counter-productive.  Sometimes a simpler, more classical approach may work better. Though that is a subject for other studies.  Considering this study was conducted on in-season athletes who are already under tremendous demand both on their time and recovery abilities, a lower volume, simpler program may be more appropriate and productive.

Variable resistance increases upper body strength and power more than traditional training

Today it is not uncommon to walk into a gym and find someone slinging up large elastic bands or chains over their squat or bench press bar.  Sure it looks like the person knows something that you don’t but are they really onto something or is this just another adventure in being creative trumps actual science?  Well in this case they are actually onto something that can be beneficial for certain training populations.

Riviere et al. (2017) compared variable resistance training to traditional resistance training and measured strength and power adaptations in elite youth rugby athletes.  Both groups underwent an identical resistance training program twice a week with the first workout emphasizing strength and the second workout emphasizing power.  The only difference between the two subject groups was that the variable resistance group used elastic bands equal to 20% of the prescribed load on their bench press.

The researchers measured 1 repetition maximum (1RM) in the bench press along with mean velocity and power at 35, 45, 65, 75 and 85% of 1RM.  After six weeks of training the subjects were retested.  Both groups improved their 1RM but the variable resistance group showed greater results.

For mean velocity measurements the variable resistance group showed small improvements at 35 and 45% of 1RM, medium sized changes at 65% and large improvements at 75 and 85% 1RM.  The traditional training group only showed small improvements at all levels of resistance.

Results for mean power were similar to the velocity measurements with the variable resistance group showing smaller changes at the lower levels of resistance and greater improvements at higher resistance levels.  The traditional group saw only trivial improvements in absolute mean power at all resistance levels and for relative power saw trivial changes for all levels except 85% 1RM where the changes were considered small.

So what does this all mean?  Both groups did improve their bench press strength, velocity and power but the variable resistance group clearly had larger improvements, especially at higher levels of resistance in the velocity/power measurements.  This supports the results of other studies that showed strength benefits utilizing variable resistance were greater than with traditional training though this was, according to the authors, the first study to look at power under these circumstances.

The authors offer 4 possible reasons for why variable resistance resulted in greater improvements.  1) During the eccentric phase there is an increase in the storage of elastic energy within the body which can be tapped into during the concentric portion of the lift which could result in more training stimulus leading to the gains. 2) The point at which the movement arms are at peak mechanical disadvantage, the sticking point, is the limiting factor in force production and how much resistance can be utilized.  Variable resistance can be used to work around this sticking point so there is more muscle tension during the later stages of concentric portion of the lift. 3) Normally there is a deceleration phase at the end of the concentric portion of the lift which is overcome with a greater constant acceleration through the entire movement when variable resistance is used.  This constant acceleration through the end of the lift can add to greater strength and power.  4) Variable resistance training forces more neuromuscular adaptations including the recruitment of larger motor units in the eccentric portions of the lift.  Collectively these factors lead to greater changes over time.

The greater improvements in velocity that occurred at higher levels of resistance may have been because the subjects used higher levels of resistance during their actual training protocol.  This allowed the subjects to show greater improvement at testing levels closer to their training resistances and smaller changes at resistance levels they did not train near.  The variable resistance group also showed larger differences in power then the traditional group as the resistance levels increased.  This is most likely because of the increased gains in velocity the variable group experience at higher resistance levels which allowed them to produce more power at those same resistance levels.

Now that we’ve established that variable resistance appears to offer increased improvements over traditional training, at least in the bench press, let’s put the brakes on before you rush out and start wrapping elastic bands around all of your bars.  First, the study had a very small population and only used one lift with variable resistance.  As we all should know by now, studies with small populations have only so much power and may not hold true for all circumstances, groups and other variations in training.  Secondly the study was done elite youth rugby players.  This means they are young, healthy, and participate in a sport where increased upper body strength and power is related to performance.  While it is probably safe to say that other trained athletes can experience similar results this doesn’t mean every personal training client in the gym should suddenly be using variable resistance in this way.

I want to shake my head and scream every time I see a less experienced and educated trainer putting an inexperienced, older or relatively unstable and weaker client under a bar with bands attached to it just because they saw one of the stronger, more experienced trainers in the gym using this technique in their own training.  Even worse, when a more experienced trainer shares the technique without really understanding it and with more concern about how they look to their younger colleagues instead of what is best for a particular client.  If someone cannot do a few sets of great body weight pushups and already do a bench press with a respectable level of resistance they probably should never be using variable resistance until they have already developed a great strength base with traditional training techniques.

Note that the elastic resistance used was equivalent to 20% of the prescribed training load. This means the subjects weren’t trying to use exceptionally challenging level of variable resistance.  They wanted enough resistance to enable the desired adaptations but not so much that the focus of the lift became dealing with the variable resistance levels instead of maintaining great form and focusing on the overall lift.  It would be very interesting to see a study that compares different percentages of variable resistance but I would hypothesize that after a certain point we would see reduced benefits.  It doesn’t take a lot of variable resistance to work around the sticking points and provide greater acceleration at the end of concentric lifts.  I would strongly suggest until we have a body of literature suggesting otherwise that if someone uses variable resistance they choose lower levels of resistance and limit themselves to something in the neighborhood of 20-25% of their total load.  Certainly if they are training at total loads closer to their 1RM.

Works cited:

Hammami, M., Negra, Y., Shepard, R., Chelly, M. (2017) The Effect of Standard Strength vs. Contrast Strength Training on the Development of Sprint, Agility, Repeated Change of Direction and Jump in Junior Male Soccer Players. Journal of Strength & Conditioning Research. 31:4: 901-912

Hwang, P., Andre, T., McKinley-Barnard, S., Morales Marroquin, F., Gann, J., Song, J., Willoughby, D. (2017) Resistance Training Induced Elevations in Muscular Strength in Trained Men Are Maintained After 2 Weeks of Detraining and Not Differentially Affected by Whey Protein Supplementation. Journal of Strength & Conditioning Research. 31:4: 869-881.

Riviera, M., Louit, L., Strokosch, A., Seitz, L. (2017) Variable Resistance Training Promotes Greater Strength and Power Adaptations Than Traditional Resistance Training in Elite Youth Rugby League Players. Journal of Strength & Conditioning Research 31:4: 947-955

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