Posts tagged “dragon

Physics of Acceleration

Acceleration = (final velocity – initial velocity) / (time at finish – time at start)

Basically, the more you change your speed in a shorter amount of time, the more you have accelerated.  Having a race start that features high acceleration is often a strong deciding factor in races of shorter distance and where the average speed of boats are closely matched.  With the 2017 CDBA Sprint Races just having finished this past weekend, it’s time for teams to start working the long game in prep for more 500m racing fun this summer.

What I wanted to write about regarding acceleration in race starts is to address the wide variation in how teams fiddle with stroke counts and stroke technique in hopes of finding an edge over their competitors.

Many coaches I’ve spoken with over the years often have one of two philosophies about race starts: don’t fix what isn’t broken OR try something different.  The leave-it-be coaches may have strong personal histories of success utilizing a certain race start count and stroke style to the point where the idea of trying something new seems like it would hurt more than help team performance.  That fear is completely understandable, and in certain cases, may be quite accurate.  Think of the novice team trying dragon boat for their first race.  The ‘ole 5-10-10 presents both a great mental and physical challenge with plenty of clacking paddles and drenched partners.  Chances are that coaching different rate ratios and stroke techniques would probably be lost upon such a crew because performance is being limited by base skill.  Now, take the elite paddling crew; each paddler with multiple years of racing experience and a high level of fitness.  If we’re referring to a tight-knit crew with at most 1-2 new additions vs a thrown-together “dream team,” tweaking the start might also be a waste of time because the crew has perfected their start and any change is, again, probably a waste of time.

So why chase new and different race starts at all?  My answer is: because no crew is the same as the next.

Getting back to acceleration, the basic philosophy of a race start is to get from dead stop at the starting line to race pace as quickly as possible.  I’ll ignore “as efficiently as possible” because when it comes to 500m or less, who cares who did it the cleanest if they lost to a team with a “messy” start?  If efficiency was poor in the faster team, it just means that team could have accelerated faster next time.  To me, a winning start is plenty efficient no matter how it looks.  Think of how noisy, messy, and almost out of control a drag race car start is compared to driving around your Prius.  The dragster was efficient at accelerating like a beast while the Prius was efficient at saving fuel and not waking the neighbors.  The dragster wins.  Be the dragster.

But how do you know if a start is giving efficient acceleration?  Well, you could test like I used to with a GPS and stopwatch or utilize buoys of known distance.  Find your team’s sustainable race pace and seek to get to that speed ASAP.  There’s the chance for playing around with ratios and technique.  The goal is to eliminate dead-spots in acceleration on the way to full race pace.  The other goal is NOT to completely overshoot race pace and exhaust the crew before you get past the 100m mark (unless 100m is the race).

On to ratios and technique, faster acceleration demands a greater amount of power.  Power is the rate at which work is done.  Each paddle stroke does some work.  Stroke too long and slowly and power is lost.  Rate up too quickly and shorten the stroke, power is also lost.  The sweet spot for every team lies in the middle somewhere.  Physically stronger, more explosive teams can afford to rate up faster because they can put out more power.  Weaker teams may benefit from an intentionally more gradual workup.

Once the start is over, the time to accelerate is done.  Some teams opt for a high stroke rate during the race because it seems “faster.” (as in people moving their bodies/paddles quickly must be making the boat move faster, right?)  Well, again it depends on how the team can physically maintain their chosen race velocity.  If the team can ONLY generate adequate power to sustain that chosen speed, then sure, thrash away.  Their hearts will probably be running a few extra beats/min higher than a team that is able to maintain the same boat speed but at a lower stroke rate.  If you have a paddling erg, you can see how your heart rate changes if you decrease the paddle resistance and hold a higher stroke rate during a time trial vs a slightly heavier pull but lower stroke rate over the same distance.

Case in point, you can see how DW drops the stroke rate but maintains their boat speed while other adjacent teams maintain high stroke rate without gaining ground:

Compare that to our video from the 2009 Sprint Race where SFL was doing dry starts with rather meek acceleration between strokes 0-2.  I definitely do not think the strongest SFL team of its day could stand up to the crews of today, mostly based on the average physical fitness of modern, A-div teams.

I’m still proud to say that I was able to coach a crew of highly dedicated and passionate paddlers of a wide variety of fitness levels and skill into becoming a consistent contender for A-div podiums over the course of several seasons.  Thanks for the memories, everybody!


Musings: The Stretch/Shortening Cycle

Athletes have long noticed that bouncing helps increase power immediately before a power activity.  Ever see somebody struggle to chest press too much weight?  They may literally bounce the bar off their chest, which can fracture their ribs but also give what’s called an active, eccentric stretch to the pec major, triceps, and deltoid muscles; increasing their power output temporarily.

Try this: get a chair and squat down to lightly touch your bottom to the seat.  Then, try to jump as high as you can (ideally you’d have a marker to know how high you jumped).  Now, try removing the chair and squatting down to the same height, allowing your hips to quickly dip down into the squat right before the jump (an ordinary, stationary squat jump).  You should notice that you can jump higher when you take the chair away.

Notice how those tasty frog legs move slightly before the body starts to move in the leap

You are giving your leg muscles a quick stretch prior to the jump, which increases the power and thus the height of your jump.

This phenomenon should happen in our arm and trunk muscles as well.

One might wonder, if you could coordinate an entire boat of 20 paddlers bouncing slightly before the first stroke of a start, you could get a significant increase in power on the first stroke!

This may already happen instinctively in the form of “The Trunk Bob” immediately leading up to the first stroke.  What this does is bring the trunk downwards while the arms ever-so-briefly stay stationary, stretching the mighty latissimus dorsi muscle before it contracts and pulls through the first stroke.

Check out The Trunk Bob

Will a slight bounce help make a more powerful first stroke?  How much does the first stroke REALLY matter if everything counts in a race?

Nobody knows for sure, but it sure does make me wonder.


Stretch before paddling?

It’s a very common belief that stretching to reduce muscle tightness is positively linked to performance, however evidence shows that some forms of stretching may actually be bad for performance.

When it comes to dragon boat, is it a good thing to stretch?

Will it help or hurt your paddling performance?

Let’s look at key features of different types of stretching.

Static Stretching

This is a slow and constant stretch performed either actively (under your own power) or passively (with some help from another person or object), held at an end position typically for 30 seconds or longer.

Dragon boaters performing static stretches.

The Good

Static stretching is a simple method to increase range of motion (aka flexibility) with potentially decreased risk of injury  during the stretch.  If you’re a paddler who can’t paddle with good form despite having good water experience because of muscle tightness, then this method may be of benefit to you to improve flexibility between practices.

The Bad

Studies show that static stretching has a negative impact on a muscle’s ability to produce peak force and power.  In terms of sprinters and weight lifters, sprint times and one-rep max values were made worse immediately following a prolonged, static stretch to the muscles being used.  Why does this happen?  Our muscles have different sensory receptors within them that help us produce force quickly (creating power) and static stretching is thought to reduce the activity of these receptors.

Static stretching also causes muscles to decrease in temperature due to not actively contracting them.  This means you may lose the benefits of doing a warm-up if you statically stretch muscles for several minutes.

Doing static stretching prior to races or at the start line?  Evidence may suggest you’ll have a lower ability to exert power during your paddling.

Ballistic Stretching

This is an active effort using bouncing-type movements where the end position of the stretch is occupied only briefly.

The Good

Unfortunately, there is not very much evidence at all that says ballistic stretching has any clear benefit to athletic performance (so far).  This means that ballistic stretching is not a dependable way to improve performance.

The Bad

There is evidence (1) that says ballistic stretching may actually increase risk of injury to affected muscle groups, especially if these muscles have been injured in the past.  Remember those stretch receptors mentioned earlier?  Their job is to contract a muscle in the event that extra force is suddenly detected (eg you are holding an empty catcher’s mitt in front of you with your eyes closed and somebody drops a softball into it.  Your hand doesn’t fall because your muscles contract to keep the mitt in place).  Ballistic stretching exerts tension on a muscle in a quick manner that activates these same receptors, causing muscles to tense up at the end of the ballistic movement, defeating the purpose of the stretch.

Dynamic Stretching

This form of stretching can be defined as a “functionally based stretching exercise that uses sport-specific movements to prepare the body for activity” (2).  They are active movements made within the range of motion required for a sport, ideally in directions that mimic the sport itself.

A dynamic paddler warming up dynamically

The Good

Dynamic stretching is a more controlled, gentle method for stretching and in this regard, minimizes the risks present with ballistic methods.  Dynamic stretching can gradually increase tissue temperature, which improves the ability for tissue to accept loads safely.

The Bad

There aren’t very many “bad” aspects of dynamic stretching, but this method of stretching has not been found as effective at increasing static range of motion (3).

HOW do you put it all together?

A good series of dynamic stretches as a warm up for dragon boat involves closely mimicking the movements performed in the actual sport.  These movements should be kept non-ballistic without bouncing in/out of the end range of your joints and tissues.  For example, you could perform “air” paddling on land with your hands and no paddle, working on gradually progressive reach, rotation, and leg drive an even number of times per side.  As you continue, try to gradually increase the speed of movement (rate it up!) to increase your body temperature by getting your blood pumping!  “Air” paddling is just one idea for a dynamic warm-up.  You could gradually move your arms, legs, and trunk in sport-similar movements to similar results.

After the race is over, feel free to statically stretch as a cool down by holding your stretches for ~30 seconds within a comfortable amount of tension to maintain range of motion and reduce post-exercise tightness.

In any stretching routine, you should never push into feeling pain as this may mean you are exceeding the capacity of your tissues and possibly causing injury.

Keep it dynamic everyone!

1.  Clarkson, P., and I. Tremblay.  “Exercise-induced muscle damage, repair, and adaptation in humans.”  J Appl Physiol. Jul;65(1):1-6.1988

2.  Mann, D.P., and M.T. Jones.  Guidelines to the implementation of a dynamic stretching program.  Strength Cond J. 21(6):53-55. 1999

3.  Bandy, W.D., J.M. Irion, and M. Briggler.  The effect of time on static stretch on the flexibility of the hamstring muscles.  J Orthop Sports Phys Ther 27(4): 295-300. 1998

4.  Baechle, T.R., and R.W.  Earle.  Essentials of strength training and conditioning; 3rd edition.  National strength and conditioning association. 2008