Thursday, April 9, 2015

Using the Tempo Trainer for pacing interval workouts on the track

The Tempo Trainer
As a high school coach, one of the toughest things to teach young runners is proper pacing.  Everyone has seen a high schooler who takes off far too fast in a mile or two-mile race, only to stagger home disappointed and out of energy at the end.  Pacing in races is obviously important, but so is pacing in workouts.  An improperly-paced interval session can ruin the intended purpose of the workout.

Take, for example, a staple high-end aerobic session: "cruise interval" kilometer repeats done at the anaerobic threshold.  A high school runner who is currently in 9:55 3200m shape might be looking to run 6x1km at around 3:30 per kilometer with a minute's rest between each.  When done properly, running each repeat at an even pace, this is a fairly relaxed workout.  However, if poorly paced, it quickly becomes a lot more challenging. 

For an experienced runner or a coach, it can seem baffling when a new runner is incapable of pacing.  Younger runners haven't developed their own internal sense of pacing yet, so they struggle to hit prescribed workout paces, even if the workout isn't inherently difficult. 

Can't you just check your watch every 200 meters? Frequent watch-checking is the most obvious solution, but this brings along a host of problems.  First, you're relying on all of the runners you are coaching to remember to bring a watch, which can be its own struggle.  Second, a watch only allows you to check cumulative times; adding up splits in your head can be a little tricky if you aren't running a mathematically convenient pace.

The proper pace for a 3:30 kilometer is 42.0 seconds per 200 meters.  What I'll often see when a group of high school runners attempts to run this pace is wild variation in the per-200m split, alternating between too fast and too slow.  So, a group might run the assigned pace of 3:30, but will do it with intermediate splits of 39 - 41 - 44 - 44 - 42.  Hardly ideal! You can take a split each 200 on your watch, but then you can't report your overall time to your coach.  Using the watch to gauge pacing can also lead to overcorrection: running a 40-second 200 to "get back on pace" by 400 meters, following a first 200m split of 44 seconds, for example. 

Discovering the Tempo Trainer

Through a combination of luck and resourcefulness, I stumbled across a more robust solution.  In the fall, I suffered a case of Achilles tendonitis which led to a few weeks of aqua-jogging in the pool to maintain my fitness.  I shared pool space with a club swimming team which occasionally used a small pacing device called the Tempo Trainer to help them set their stroke rate (much like some runners use a portable metronome to assist with setting their stride rate).  The waterproof unit was meant to be tucked inside a swimmer's swimcap and was loud enough to be heard underwater. 

It wasn't until I mentioned the Tempo Trainer to a swimmer friend of mine that I realized that it could be used for pacing interval workouts as well.  My friend remarked that she often used its pacing function so she could hear a "beep" at a prescribed interval during long repeats in the pool.  So, for example, if she wanted to swim a 100 yard repeat in 66 seconds, she'd set the Tempo Trainer to beep every 16.5 seconds, so she'd hear it each time she pushed off each wall in a 25 yard pool.  By judging whether the beep was early or late, she'd be able to tell whether she was ahead, behind, or on pace.

Hearing this reminded me of a special workout called the "Faraggiana-Gigliotti Test" that Italian running coach Renato Canova conducts on his top marathon runners.  The test involves taking blood lactate samples after a series of 2km repeats at a range of potential marathon paces to get a reasonable estimate of an athlete's current marathon fitness.  To ensure his athletes pace each two-kilometer repeat as efficiently as possible, the coach sets out cones every 25m and uses a loud beeper set to beep at the proper interval for the required pace.  As John Kellogg has pointed out, doing so requires the beeper to be placed in the center of the infield, so you don't get pacing variations due to the speed of sound as you round the track.  One central beeper also has to be loud enough to be heard from the other side of the track, and you can only use it for one workout group at a time.  Finally, unless a coach manually resets it or changes the beep interval, the athlete has no control over it. 

The Tempo Trainer circumvents all of these limitations.  It's small enough to easily be carried in your hand during a workout, and it is loud enough to be heard even while running in a group, but not so loud that everyone within a quarter-mile can hear. A large track or cross country team could use one Tempo Trainer for each workout group.  Finally, if you get sick of it, you can turn it off and toss it on the infield.  It also comes with a clip that you could use to attach it to your shorts, but I found it easier to just carry it in your hand.  After doing some research, I bought one and tested it out. 


Using the Tempo Trainer to pace intervals

The device has three modes, a short-interval repeating timer, a long-interval repeating timer, and a metronome.  For a distance runner, the first function, the short-interval timer, is by far the most useful function.  The metronome is only adjustable to a precision of five beats per minute, whereas other portable metronomes can be adjusted by one beat per minute and are far cheaper.  The long-interval timer is similarly hampered by poor precision—it can function as a repeating timer for durations ranging from one second to 9:59, but only by one-second increments.  Most sports watches have a similar repeating-timer function nowadays. 

The short-duration timer, however, can be set to beep at an interval ranging from 0.20 to 99.99 seconds, with a precision of 0.01 seconds.  Moreover, the beep interval can be re-synchronized by pressing a button.  This is fantastic because it allows you to disregard poor initial pacing in a repeat and immediately get back on the proper pace. 

Placing cones every 25m along the track allows extremely precise pacing with the Tempo Trainer
The level of precision and the resynchronization capability makes the Tempo Trainer phenomenally useful for workout pacing.  To use it, I use a measuring wheel to wheel off the track, putting down cones every 25 meters on the inside of lane one.  Since cones tend to get kicked around on a busy track, it might be smarter to put down strips of tape or discrete marks along the inside of the track so you only have to wheel the track out once.  Next, I calculate the appropriate beep interval.  For example, if I wanted to run 76-second 400m pace during a workout, I would set the Tempo Trainer to beep every 4.75 seconds.  This way, the Tempo Trainer should beep just as I reach each cone if I'm running the right pace.  During the workout, if I go out too fast and hit the first cone way before the beep, I simply wait until I get to the cone at 50 meters and press the button to resynchronize the beep interval.  This allows me to "throw out" the first 50m of poor pacing and run the rest of my repeat at the right speed, instead of trying to make up for lost time by slowing down, then speeding up again.

The 0.01 second precision of the Tempo Trainer allows for adjusting 400m times by 0.16 second increments, which should be precise enough for any workout a middle or long-distance runner would ever do.  If you aren't as picky with precision, you could just as easily calculate the proper beep intervals for 50m or 100m splits.

Using the Tempo Trainer with high school runners

During my latest season of coaching high school track, I've put the Tempo Trainer to use with several of my high school athletes with good success.  Using the Tempo Trainer as a pacing device on the track virtually guarantees they'll run the correct pace: getting immediate pacing feedback every 4-6 seconds allows incredibly precise and even pacing in interval workouts.

My "beep chart" for a range of paces. Click to enlarge
In my coaching folder, I keep a chart with pre-calculated beep intervals (click the image on the right for a high-resolution version) for any conceivable pace I'll need for a workout.  This way, I can quickly set the Tempo Trainer to the proper beep interval and hand it off to a runner before he starts a repeat.  For now, I've been adjusting the tempo myself and only showing the runners how to re-synch the beep interval.  Adjusting the beep interval is easy, but if you accidentally get to another mode by holding down the re-synch button too long it can be a little confusing to get back to the right setting if you don't know what button to push.  A quick read-through of the instructional manual is all you need to figure out how to use the Tempo Trainer, though, and there are only three buttons. 

To prevent my runners from becoming overly reliant on the Tempo Trainer for pacing, I often have them use it for a few repeats, then take it away and see if they can keep hitting the proper splits.  All of my runners who have tried it so far say they find it quite useful—I was worried the incessant beeping would drive them crazy, but so far, that hasn't been the case!

Disadvantages of using the Tempo Trainer

As a training tool, the Tempo Trainer is not perfect.  I wish its metronome function was adjustable by one beat per minute increments, as that would make it far more useful for stride-frequency work.  It's also rather expensive—I got mine for $35 on Amazon, which is still cheaper than the $50 price tag on the manufacturer's website.  For a glorified beeper, that is quite a lot of money.  Portable digital metronomes, like those offered by Casio, can't be any more complicated from an electronics perspective, and you can buy those for less than $10.  If you're a small-electronics manufacturer and you'd like to put a beep-interval timer into production specifically for runners, drop me a line...

The Tempo Trainer is designed to be waterproof, which might account for its higher price.  However, its reviews on Amazon are middle-of-the-road.  Some customers—almost all of them swimmers—find that it stops working after a few months or a year, though the battery is replacable.  So far, I haven't had any problems, and I'm hoping that using it for running will be easier on the device, since we don't constantly submerge it in water (though the fact that it's waterproof is handy for rainy spring days). 

As mentioned above, I do believe there is a danger in becoming too accustomed to the Tempo Trainer.  A critical component of developing your own sense of pacing as a runner is learning to internalize different speeds and get a real sense of how they feel.  And of course, you won't be able to use the Tempo Trainer in a race.  An experienced runner should be able to focus on the proper effort as the supreme goal of a workout, not simply pace, especially when the workout is something that is done "by feel" like anaerobic threshold repeats. 

To this end, I don't think you should use the Tempo Trainer for every repeat of every workout.  It's not particularly useful in runners who have already developed a good sense of proper pacing either—it just gets in the way with their ability to sense the pace.  But it's still incredibly useful for younger or less-experienced runners who'd be prone to ruining a workout if left to fend for themselves, or for workouts where proper pacing is absolutely essential. 

Theoretically, the ideal way to progress away from using the Tempo Trainer for pacing would be to use a classical conditioning approach.  Once a runner is able to pace a workout properly getting pacing beeps every 25m, you could move to 50m beeps, then to 100m beeps once the previous step was mastered.  Eventually you can progress to watch-checking every 200 or 400 meters.  In practice, it's more simple to use the Tempo Trainer for a few repeats, then take it away and see whether a group can still maintain the right speed.  Often, once a group of runners gets in a "groove," it's easy to maintain proper pacing even after the feedback mechanism (the Tempo Trainer) has been removed.

When using a Tempo Trainer for workout pacing, the onus for ensuring the prescribed pace is the correct one is also squarely on the coach's shoulders.  When getting only intermittent feedback, like checking a watch every lap, runners will often self-regulate their pacing according to the conditions or their own fitness.  Of course, this is often the problem—it's windy or cold or raining and Workout Group Three, which is supposed to be running 90-second quarters, is slogging along at 96s with no real excuse.  But it doesn't take a lot of imagination to envision a scenario where you could run yourself into the ground by setting up a very aggressive workout goal, the using the Tempo Trainer to force yourself to maintain the proper pace as long as physically possible.  So, coaches who use the Tempo Trainer will need to be very careful to assign the right pace, or to instruct athletes to stop using the Tempo Trainer if the rhythm isn't right.

Finally, the Tempo Trainer is not very useful for change-of-pace workouts.  You can only set it to beep at one specific interval, and it takes time to adjust that interval.  So, using it for a workout like the classic Oregon 30-40 workout, which involves alternating 30 second 200s with 40 second 200s, is out of the question.

Why not a metronome?

Given how much more expensive the Tempo Trainer is compared to a portable digital metronome, you might be wondering why you shouldn't just use a metronome to pace your interval workouts instead.  I investigated this possibility, but it turns out that a typical metronome, which is adjustable by one beat per minute, is not accurate enough to provide pacing feedback.  Most metronomes don't go any lower than 30 beats per minute—far too fast for many running speeds, even with 10m cones! 

Some metronomes allow you to set a beat time so that every fourth beat is a different pitch, which might allow you to expand the range of possible "paceable speeds."  However, because a metronome measures beep intervals in beeps per minute, it scales inversely with lap times on a track, which are measured in minutes per distance.  By doing the math, we can see that you can only adjust your beep interval by 1-1.5 seconds over 400 meters within the most common range of paces you'll encounter at the high school level (96-64 seconds per 400), and your ability to change increments does not scale well.  For example, using a metronome at 1/4 time, you can pace yourself to an 80.00 second 400m with 48 bpm (a beat every 1.5 sec and a higher pitched beep every 5.0 seconds), and a 78.37-second 400, with 49 bpm.  If you want to run 79.00, you're out of luck.

The difference in beep intervals is also a problem at slower speeds.  1.63 second precision at 80-second 400m pace might not seem so bad, but running 90-second 400m pace brings your precision down to 2.13 seconds per lap (in 1/4 time, 42 bpm = 91.43, and 43 bpm = 89.30). 

In contrast, because the Tempo Trainer can set its beep interval in the units of seconds per beep, with a precision of 0.01 seconds, it can set your 400 pace in 0.16 second increments regardless of how fast or slow you run, assuming you use 25 meter cones.   


Conclusion

Despite the drawbacks, the Tempo Trainer is an immensely useful tool for a coach.  When used properly, it allows for virtually perfect pacing, and it's fairly idiot-proof (though high schoolers will surprise you!).  The Tempo Trainer allows us to do more advanced workouts, like long repeats at the anaerobic threshold, which aren't usually possible to do correctly as an inexperienced runner.  It is also very useful for situations where slight variations in pace can make a workout catastrophically more difficult, as is the case with some endurance-type workouts for middle-distance runners.  Furthermore, the ability to "throw out" improper pacing early on in a repeat and continue at the correct pace, instead of making up for lost time, is quite valuable.  In a pinch, it can also double as a metronome for adjusting an athlete's stride frequency. 

If you have some extra money in your budget and you'd like to see your runners learn to pace their workouts better, it might be worth your while to invest in a few Tempo Trainers for your team.  By combining the Tempo Trainer with GPS watches, you could (though maybe not should) accurately and precisely control the pacing of your runners during all periods of training. 

The Tempo Trainer could also be useful for individual runners who struggle with proper pacing during interval workouts.  Even if you don't have a measuring wheel and can't mark out 25-meter segments on your local track, you can still use the Tempo Trainer for 100m beep intervals, which are clearly marked on any standard track.  If, like me, you are a fairly experienced runner who can usually hit a prescribed 400m pace within a second or so, the Tempo Trainer is probably not worth your time.  Once you've developed the ability to sense the connection between your internal effort and the external pace that results, you're beyond the need for pacing feedback every twenty-five meters. 

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