An often-overlooked component of training, especially among boot camp instructors, is tempo.  Tempo refers to the speed at which a repetition is performed with each repetition being broken down into the three distinct phases in the movements of muscles and tendons:

-          Lowering (eccentric) portion

-          Pause (isometric) portion

-          Lifting (concentric) portion

Unfortunately, most boot camp workouts only go at one speed… FAST! 

Lifting weights too fast can lead to many problems, the most obvious one being injuries.  It’s critical that trainees lift with good form to both properly challenge the muscles of the body as well as avoid injuries.  If a beginner who hasn’t learned proper technique just starts throwing weights around they’re bound to get hurt, and if not, they’re still going to be less than satisfied with their results.  Lifting technique is critical for success, and when it comes to the relationship between speed and technique just remember that speed makes bad technique even worse!

On the flip side, the most widely accepted advice on tempo among fitness professionals is that you should lift and lower weights under full muscular “control” in a smooth, rhythmic fashion.  This generally leads to a 2-0-1 tempo.  For example, in the case of a squat you would lower your body for two seconds and then take one second to return to the starting position.  While this is a much safer approach and will certainly create positive physical changes, it’s certainly not the only way to train…

Subtle differences in tempo can have extremely significant impacts on results, as research and practical application have shown that muscles respond differently to varying training tempos. 

In addition, deliberately focusing an entire training session on just one aspect of the repetition range (eccentric, isometric, concentric) will yield great benefits, as well as offer variety and fun to your overall weight loss and fitness training program.  It is this particular focus that we’ll be employing in our boot camp training program this month.

Eccentric Training

Science is proving what many bodybuilding experts have been preaching for years – that the negative, or eccentric, part of a repetition is extremely important for size and strength gains.  In fact, in a now famous (among fitness geeks like me) informal study, Nautilus creator Arthur Jones put Casey Viator on an eccentric-only training routine.   According to Jones, “in five weeks of negative-only workouts Casey added seven pounds of bodyweight while increasing his muscularity.”  In other words, he built muscle AND lost fat!

Eccentric training focuses on slowing down the elongation of a muscle and tendon group. In other words, it serves as a braking mechanism to protect your joints from damage prior to a subsequent concentric contraction. It’s critical to note that the vast majority of all chronic and acute injuries occur during deceleration type movements such as landing from a jump, quickly changing direction, or suddenly falling down. Think of eccentric training as sharpening your brakes so that your muscles and tendons are properly able to absorb kinetic energy and thus control any sudden or repetitive deceleration forces that may come your way. For this reason, it’s second to know for improving performance and reducing the risk of injuries in sport.

For example, when doing an eccentric step-up, you begin standing on top of a box or bench and then slowly take 5-seconds to lower yourself to the floor while staying tall up top and loading the heel of your support leg so the knee and ankle stay aligned. This exercise is unmatched for developing knee, ankle, and hip stability and building your quad and glute muscles to take pressure off of your knee during explosive movements like running and jumping. For this reason, this is one my favorite exercises to bulletproof the knees and is just what the doctor ordered for people with chronic knee pain from conditions such patellar tendonitis (“jumper’s knee”) or arthritis. In fact, if you are unable to do multiple sets of multiple reps of eccentric step-ups with 5-second lowerings on a high box where your front thigh is parallel to the floor at the bottom of the movement in a pain-free environment, then you have no business running or jumping whatsoever unless your goal is a traumatic knee injury.

Why 5-second lowerings? First it’s important to note that tendons connect muscles to bones. Using the step-up example above, your patellar tendon connects your quad muscle to your knee cap. Well it takes a full 4 seconds to eliminate the aforementioned stretch reflex, or stored elastic energy, in your muscle and tendon groups. Subsequently, this is why eccentric training works great in rehab settings for conditions such as tendinosis because it takes the bounciness of the tendons out of the movement and forces the muscles to do all of the work. In this way, the muscles grow stronger to take pressure off of the tendons it works in conjunction with working against deceleration forces.

One reason eccentric training may be so effective for muscle growth is because of the significant microtrauma it causes to muscle tissue. This skyrockets metabolism as the body is forced to busily repair all those damaged muscle fibers. “Eccentric actions place a stretch on the sarcomeres to the point where the myofilaments (myosin and actin) may experience strain, otherwise known as exercise induced delayed onset muscle soreness (DOMS)” (Aaron Bubbico & Len Kravitz, 2010). There’s a large body of evidence suggesting that muscular damage is associated with increased muscle growth, although research is still inconclusive in this area (Brentano et al. 2011; Komulainen et al. 2000; Zanchi et al. 2010). 

Plus, you are much stronger eccentrically than concentrically because your muscles can oppose more force than they can generate. Think about how much easier it is for you to sit down into a chair than to get up and stand out of it. This is why the best way to be able to learn how to perform challenging bodyweight movements like push-ups and pull-ups through a full range of motion is by first mastering the lowering portion. Finally, since your muscles are elongating during the eccentric portion of a movement this leads to greater total muscle recruitment and subsequently a great stimulus for muscle growth. For all of these reasons, eccentric training is a well known tool to break through any frustrating strength, muscle-building, or weight loss plateaus.

However, caution is advised when it comes to eccentric-only training.  It is extremely taxing and can lead to severe soreness as mentioned earlier.  It’s very important that eccentric-only training is performed in limited amounts for a limited period of time. 

Finally, when designing an eccentric-only workout, it’s best to choose exercises that are “self-limiting” meaning that you won’t be able to finish a rep if your form is bad. Also, be sure to choose exercises that won’t place you in a dangerous position when you reach total muscle failure that would require a spotter like barbell squats or bench presses.  That’s why exercises such as push-up, bodyweight row, single-leg squat, and step-up variations work great for eccentric-only training. After all, no one has ever died from collapsing to the floor while lowering from the top of a push-up – but sadly they have from bench pressing.

Isometric Training

An isometric contraction is a contraction of the target muscle in static positions at a specific joint angle in which tension is developed, but there is no change in the length of that target muscle (no movement).  Tension can be developed by exerting force against immovable objects (overcoming isometrics) or by statically contracting a muscle to resist against an external force (gravity or added resistance) that ‘s attempting to force you into an eccentric contraction (yielding isometrics).

It is important to note that isometric training only increases strength at the specific joint angles in which the exercise is performed (e.g. statically holding the bottom of a push-up position about 1-2 inches off of the floor) where the classic dynamic exercises (e.g. dynamically performing a push-up where you lower your chest to the floor and back up to the top position) increases strength throughout the full range of motion of an exercise. However, isometric contractions can improve maximal strength at specific joint angles better than their dynamic counterparts. This is because dynamic exercises are often performed very quickly and engage the stretch reflex – the natural bounciness, or elasticity, of your muscles and connective tissues – so that some muscle fibers will not be fully activated due to force contributions from your tendons. The best example of this is how much more your muscles burn when you slowly walk up the stairs rather than quickly running up the stairs.

Though isometric training has traditionally been popularized by yoga and Chinese martial arts like Kung Fu, it can and should be used for general strength and conditioning as well.  It’s also a popular training tool in rehab situations because as I mentioned earlier, it helps strengthen the muscles at very specific joint angles and weak points. Plus, when properly applied, isometrics don’t place undue stress on the joints like other fast, high-impact dynamic exercises can because it takes the tendons out of the movement (think tendonitis of the knee caused by lots of running and jumping).

Isometric holds can also be used to significantly increase training intensity because you generally are able to hold a heavier weight than you can actually lift (concentric training).  Bodybuilders and strength athletes will often use isometric holds at the end of a set to train “beyond failure” thus creating a greater stimulus for muscle and strength gains.

In a boot camp setting, where the goal is to develop a “tight and toned body” along with improving strength, endurance, balance and function isometric-only exercises can add great benefits.  They’re also mentally challenging and can be a lot of fun.

In this case, isometrics work best with core exercises like pillar variations and postural exercises like resisted scapular retractions and depressions.  Isometric training is also great for single-leg balance hold variations, and specifically targeting weak points of movements such as the bottom of a squat or at the top of a hip extension hold.

Furthermore, isometric holds performed at joint range of motion extremes are great for increasing muscle flexibility and joint mobility. For example, holding the bottom of a split squat with your front thigh parallel to the floor is a great way to not only strengthen the muscles and knee, hip, and ankle stabilizers of the lead leg, but also to increase the quad and hip flexor flexibility of your trail leg.

Now, I believe the best way to get the most out of your isometric training is by opting to perform short 10-second work periods of isometric contractions with brief rest periods between them.

Why 10 seconds for the core stability holds?

Well, it’s simple- it’s about QUALITY over QUANTITY.

When most people perform isometric holds for 30-60+ seconds they tend to spend a majority of the time in compensated positions due to fatigue. This really prevents the trainee from getting the maximum benefit from performing the exercise. In other words, long sets make us weak and make us cheat.

However, if we shift the focus on maximum activation and contraction with short, focused 10-second holds we get more bang for our back.

For example, which option outlined below sounds like it has a greater benefit:

Perform ONE low intensity, wobbly, shoddy front plank for minutes on end OR perform many sets of maximum effort 10-second front plank holds with perfect form and technique for the same total time-under-tension (TUT)?

If you chose the latter then you are indeed correct. If it’s the same total volume (or TUT) there will be greater muscle recruitment with the submaximal repeat set format and thus a better overall training effect.

In fact, it’s quite similar in nature to the whole Escalating Density Training (EDT) format popularized by legendary strength coach Charles Staley in his book Muscle Logic. Staley claims that better short and long-term results will occur from multiple sets of submaximal reps then a single set of maximal effort.

I believe this whole 10-second core stability concept stemmed from Gray Cook who is a world-renowned physical therapist well known for his Functional Movement Screen (FMS).

Here is what master Physical Therapist Dr. Kareem Samhouri says about the whole 10-second isometric hold concept and here’s his direct reply:

“10 seconds for isometrics?  I give exception to the plank b/c your ‘core’ needs to be ‘on’ for up to 60-90 seconds at a time during various activities.  Athletes need to go longer than this if they are endurance athletes, but this is not max contraction. Other exercises, with a non-lengthening/shortening contraction, as follows:

 - Your muscle takes 2 seconds to ramp up intensity

- You can sustain maximal motor unit recruitment for 6 seconds

- Your muscle will then ramp down for 2 seconds

- 2 + 6 + 2 = 10 seconds: The optimal isometric contraction is 10 seconds as a result

Hope this helps!”

Does this mean you can or should never do 30-60+ second core stability holds again?

NO!

As Dr. K noted, long-duration core stability holds have their place for endurance athletes or people with advanced core stability.

But it does mean that 10 seconds is the optimal length of time to work on isometric strength and it’s most likely a better fit for the general population, especially for entry-level core programming.

There isn’t much in the way of studies or literature supporting this 10-second core stability concept, but I’m sure there will be in the years to come as some of the top trainers and coaches in the world are using it with great success with their clients and athletes.

Concentric Training

 The concentric portion of a muscular contraction is the most obvious portion.  It’s the lifting, pressing or pulling portion.

Oftentimes, uneducated or sloppy lifters will only focus on the concentric portion of an exercise by lifting the weight in a controlled fashion only to follow it by “dropping” the weight back to the starting position.  Just picture your gym-rat meathead who grunts his way through a way-too-heavy bench press and then drops the weight back to his chest before moaning his way through another ugly rep.  This has proven to be a very ineffective way of training for long-term gains, and is also more likely to lead to injuries.

However, when performed properly, concentric “focused” training has a significant place in your overall training regimen.  Let’s take a closer look…

First, let’s quickly review Olympic lifting.  The Olympic lifts consist of the clean & jerk and the snatch.  These lifts are entirely concentric because the lifter’s only goal is to rip the weight off the floor and get it to the end position.  Once achieved, the lifter will actually drop the weight…there is no eccentric portion to the exercise. 

You certainly can’t argue with the athleticism and fitness level of these lifters.  In fact, some would say that the Olympic lifts and their component exercises are the most beneficial exercises for total fitness.  After all, these exercises involve the entire body as one functional unit, place a tremendous workload on the muscular and cardiovascular system, burn a ton of calories in a short period of time, and create an enormous post-workout metabolic boost.  Pretty awesome, right?

Of course, not everyone has access to Olympic lifting equipment or a qualified Olympic lifting coach, but there are other ways to perform concentric-focused workouts.  For one, kettlebell variations can be just as effective, are generally easier to learn, and are far more convenient than traditional Olympic barbell lifts. 

Another variation on the concentric-focused training theme is to select exercises that focus on explosive movements like punching, kicking, throwing, and spearing.  You can also use ropes for pulling and sleds for dragging.  The options are endless…

Tempo Interval Training Boot Camp Template

Workout A- Eccentric Training

Workout B- Isometric Training

Workout C- Concentric Training