Monday, 20 July 2009

P-K on the Roads and Summer Holidays Tips

P-K athletes-- both local and on-line-- were active on the summer road racing scene over the weekend, led by Dylan Wykes' fine mid-marathon-build outing at the Acura 10 miler in Toronto (results, story and pics available from A solid interval session on Thursday (7x1k @ low 2:50s on trails, with a 200m jog recovery, preceded by a 30mins a.m. run and a 25min warm-up)and a good recovery day on Friday settled the issue about whether to approach this one as a tempo-pace effort or attack it for the win. Despite having upwards of 150kms for the week on board before starting his warm-up, Dylan would decide to race rather than train this one. Eschewing coyness, Dylan hit the front shortly after 2k and did his share to keep the race on the right side of 3min/kms up till the 14k mark, at which point eventual winner (low-28 10k man Hosea Kibet, whom Dylan described as a gazelle-like in the lightness and ease of his stride) took charge. Decisively beaten and on the verge of draining the glycogen tank dry, Dylan eased it in over the final couple of kms, satisfied at having done all he could competitively on the day. This will be his last all-out race effort before the World Marathon Championships in Berlin on August 22, leaving just over two weeks of hard slogging before the beginning of the final descent, so to speak, into race day.

Also competing in Toronto were new P-kers Reg Smart and Mike Gill, who hit their pace targets nicely in the 10 miler and 5k respectively, running 18:45 and 1:18 and change, their consistent hard work apparently beginning to pay dividends.

About 36 hours earlier, and on the other side of the lake, another group of us was lining up for an uncharacteristically rain-soaked edition of the Buffalo Subaru 4 Mile Chase*-- a nearly 30 year old summer staple that loops the funky Elmwood Village district of that resilient old city. Typically one of the warmest and most humid races of the year, this year's Chase was an almost chilly 63 degrees F, with and on-and-off drizzle that made it feel like a tepid day in May rather than the Dog Day of Summer that race veterans have come to expect. The highlight for our group was Paula Wiltsie's come-from-behind defense of her title in the master's women's race. (Paula continues to pull things together following her diagnosis of iron deficiency in early June). After Paula, new member Myra McDonald-- just recently a participant in the 50+ category-- surprised everyone with a money-winning 5th place finish in the master's division. (Myra didn't discover that she had done this well until, having failed to find her name in the standard age-class results, she took a look a little higher up the board!) Working down the women's age groups, Margarita Sviajine continued her strong string of racing with a win amongst the 35-39 year olds. Margarita is looking forward to mixing it up in the over-40 division starting next year. Meanwhile, Emily Tallen signaled the beginning of her rebound from illness and a disappointing nationals track 5k by finishing a strong 5th against perhaps the best women's field in the 29 year history of the race (beating her were 2 Kenyans and 2 Ethiopians with national team experience). The only P-K men entered in the race were masters Jeff Brison and Yours Truly. Jeff ran by far his best time in 3 visits to the race, solidifying his best summer of racing in years, but missed the master's money by one spot in what was perhaps the deepest over-40 field in the history of the race. I, meanwhile, ran a very flat-feeling 20:03, good for 2nd place in the master's field behind the formidable Al Arbi Khattabi, who was coming off of a strong 2nd place performance at the Boilermaker 15k only 6 days prior.

*This year marked the 29th running of the Buffalo 4 miler, eight of which I have attended, dating back to the late 1980s. This is by far my favourite summer road race, so I'd like to make a personal pitch on behalf of the event to those planning to be in its general vicinity next summer. Next year is the 30th edition of the event and is not to be missed by connoisseurs of the fine road racing experience. This race has an early evening start, and the post-race beer party on the beautiful boulevard of the Bidwell Parkway is the best I've seen in my 30 years racing in the streets. And after the official party and awards, an excellent dinner (and more beer at the superb micro-brew emporium, Coles, for those in the mood) is only a block or two away at any one of a dozen cafes and restaurants. Oh, and did I mention that the entry fee for first-timers is 10 US bucks?

Some Tips for the Holidaying Runner:

Sticking with the theme of summer running, I thought I'd offer a few simple tips on how to keep your training on track while on the road. Like everyone else, runners like to travel and escape their typical routine during the precious few weeks of the Canadian summer; but, for the serious runner, this does not include a break from the training routine-- quite the opposite, in most cases. Most serious runners I know actually like to use their time away from work to do more running, not less. Keeping to one's running and strength training schedule while away from home is,however, not easy, given how embedded our routines are in our domestic surroundings and daily perambulations: our familiar running times and routes; our regular training partners; and our gyms and home exercise rooms. And then there's the difficulty of explaining to our non-running friends and relatives why we can't have a beer at 11am because we'd like to go for a run later even on our vacation! ("Don't you ever take a break from running?", they feel free to wonder aloud).

Here, then, are a few simple tips for keeping things going while on summer vacation and out of one's training element:

1. Pack shoes that you can do both faster sessions and longer, easy runs. Since space is always a premium while on the road, bring a single pair of relatively new and lighter-weight trainers on your summer trips.

2. Remember to bring a lightweight mat on which to do your flexibility and strength work. One of the most annoying things I've found about vacationing at cottages and crowded friend's houses during the summer is the lack of a decent place to get on the ground to do my core and flexibility routine. With a small, roll-up mat, one can get outside and do this stuff almost anywhere (thereby avoiding tripping-up your uncle and causing him to spill his gin and tonic).

3. Use the "out and back progression run" in place of tempo sessions. Although the increasingly cheap wrist-born GPS is rapidly solving this problem, most travelers still confront the difficulty of getting a controlled, harder workout in on unfamiliar roads or trails. One of my tricks over the years is has been to go out in one direction for 30mins at my typical easy run effort and attempt to come back the same distance 5mins faster. This works on any surface and produces a very accurate estimation of proper tempo pace, I have found.

4.Run in the water. Many of our typical vacation spots here in Canada are close to deep and calm (at some point in the day, at least) bodies of water that are ideal option when excessive hills, dangerous traffic and/or flying bugs make running on the road a daily trial. You may have to pack a water belt for this one, but a partially deflated kid's water ring around the waist will also do the trick when added buoyancy is required.

5. Run in the mid-afternoon. Most of us stay up later while on vacation (one of the pleasures of vacationing in the first place), so trying to do your thing in the morning will just make you more tired. Besides, most of your friends and family will be tired or preoccupied in the mid-afternoon and probably won't miss you if you slip out for an hour or so. This will bring you back just in time to help with dinner prep and enjoy that best drink of the day-- the post-run beer (for my taste)! Running in the mid-afternoon will be hotter, but that will just make that other summer-specific post-run treat-- the plunge into the lake or ocean-- all the sweeter.

I'm sure there are more, but that's a start. In my experience, runners who take a few simple steps to maintain their routines-- and thus hang onto their hard-won spring conditioning-- are ultimately much happier campers than those who let it all go. Running need not monopolize you and your family's summer travels, but neither must you sacrifice your precious shape in order to enjoy some time at the lake or visiting relatives. In fact, running might even intensify your seasonal experience, since it can acquaint you even more intimately with the sounds, smells and feel of the Great Outdoors in summertime.

Monday, 6 July 2009

"So, you're a runnner? Ever run a marathon?"

There is not a serious runner anywhere who has not, at some point, had a conversation with a non-runner starting with this question. And anyone who's been at it as long as I have will know that non-runners have always understood running and the marathon to be synonymous, or at least thought that the goal of all runners was to run a marathon-- and furthermore, that any runner who hadn't run one "yet" simply lacked the conditioning to run that far! I regularly share a laugh about this with a close friend of mine who happens to be a two time Olympian and former Canadian record holder. For years she has had to patiently explain to non-running acquaintances, upon their discovery of just who she is (and such is her genuine modesty that people can have known her for years before becoming aware of her accomplishments), that she specialized in distances shorter than the marathon. In fact, I think one of the main reasons she now wishes she had gotten around to trying the marathon before injuries cut her career short is to be spared having to explain to non-runners how a former "professional" runner never managed to run 26 miles during her career! In the past 20 years, however -- the same 20 years that have seen the decline of elite distance running in places like Canada, the U.S. and the UK, about which more in a moment-- the association of running with the marathon seems to have become even more automatic, to the point where many runners themselves (albeit usually newer runners) now think of running only in terms of the 26er.

How has this happened and what does it mean for running as a competitive sport? And, is the association of distance running and the marathon necessarily wrong (should all distance runners aim to try a marathon in their future)?

The coincidence of the mainstream mass-popularity of the marathon in North America and Europe and the decline of running as a serious sport in these places (as evidenced, e.g., by relative and absolute declines in elite and serious recreational performance levels) is, like the simultaneous increase in youth participation and the sharp decline of prime-age competitors in places like Canada over the past 15-20 years, a paradox in need of reconciliation. How can it be that the second "running boom", unlike the first one-- the "jogging" craze set off in North American, many would say, by Frank Shorter's victory in the Munich Olympic marathon-- has failed to produce a corresponding increase in the number of serious competitors and in performance levels? This is particularly puzzling in the case of women, whose new-found interest in beginner's running clinics, and willingness to pay the increasingly steep cost of entering races, have been the engine of this new boom. In the 70s boom, women were also important players, albeit more as ground-breakers at the elite level than as place-fillers. The achievement of parity with men in terms of racing distances (as recently as 1972, the longest championship event for women was 1500m), including the inauguration of a women's Olympic marathon, and the professionalization of road racing for both genders, was in large part the legacy of a storming of the distance running scene by a cadre of remarkable female athletes-- people like Joan Benoit, Grete Waitz, Ingrid Kristiassen, and Rosa Mota, to name just a few-- during the 70s and 80s. As a product of this first boom myself, and as an avid reader of the magazines and books it spawned, I recall the frequency of the "fitness jogger to superstar" story line among elite women road racers in those days. This first boom, it seemed, was an immediate driver-- rather than simply a facilitator-- of elite women's running, or at least road racing, in that relatively fewer of the sport's big female names seem to have been serious, elite competitors in the age class ranks. The first running boom both drew women into the sport and dramatically raised the level and depth of performance standards, precisely as one would expect.

The paradox of running's second boom where performance is concerned can be explained, I think, in terms of its principle drivers-- the urban road race (often a marathon) as charity and/or tourist "event", and the "learn to run" business-- which often operate in symbiosis. During the first boom, road races were principally athletic contests. The most successful of these early races-- the Peachtree 10k in Atlanta, The Boilermaker 15k in Utica, the Bloomsday 12k in Spokane, the Bay To Breakers in San Francisco and, of course, the New York City Marathon-- certainly managed to attract significant numbers. In their early days, however, these races were first and foremost footraces, rather than community fitness/charity "events". Participants, whatever their age or gender, attempted to race them rather than simply complete them, and it was considered a token of failure to be reduced to walking at any point. Today, by contrast, a significant portion of the fields in these and other races aim only to cross the finish line under their own power, and often actually plan to walk significant portions of the course. This shift is amply documented in the vastly increased average finish times for almost all major road races today.

Some of the difference between then and now can be explained simply in terms of changing demographics-- the age of the average road racer, after all, has increased along with the median age in general in all developed societies. Some of it, however, is the product of a specific kind of marketing by these and other smaller races. And here is where the "learn to run" business enters the picture. Where the exploits of high profile distance runners such as Frank Shorter, Bill Rodgers and Joan Benoit tended to drive the growth of running in the first running boom, the second one has been propelled by figures like Jeff Galloway, John Bingham and, in Canada, Running Room founder John Stanton, whose stock-in-trade has been to encourage would-be runners to enter the sport with the aim simply of completing races-- i.e. without particular regard for finishing time or place. The "learn to run business", which now extends beyond the Galloways, Binghams and Stantons in the form of local store-based clinics and trainer-led operations, also tends to encourage race participation, even up to the marathon distance, for runners with only a few weeks or months experience (which is part of the reason it must discourage concern for finish time and place). The potential of these outfits to provide a steady supply of participants willing to pay increasingly high fees to participate in road races has not been lost on the promoters of road races themselves. The bigger races now routinely contract the best known advocates of the "complete not compete" movement (if they can actually afford them!) as speakers at clinics and expos as a means of both building their numbers and servicing race participants who are by now far more likely to have heard of John Stanton than world record holder Haile Gebresellasie.

From a strictly public health perspective, there is little to find fault with in this arrangement. Formerly inactive people are encouraged to become physically active, and everyone involved in the enterprise-- from race organizers and sponsors, to charities, local communities, businesses, to race participants themselves-- is receiving value for their time, effort and money. From the point of view of running as a competitive sport, however, the "second boom" model of running-- i.e. as strictly a fitness pursuit, centered around simply completing races of various distances at any speed and with as little preparation as possible-- offers very little. And it is not simply a matter of recognizing race winners-- most races do, and many still offer prize money (although, interestingly, far less than 20 years ago in relation to the dollars generated, and once inflation is factored in). The problem is that the shift of emphasis from "competing to completing" is founded on the assumption that serious training and racing are beyond the powers of ordinary people, and even perhaps dangerous and unhealthy, if one listens to some advocates of the new approach. Furthermore, over time, the idea that road racing is something to be done primarily for health maintenance-- symbolized by the "fun run"-- has made it far less attractive to younger runners, if young people are even aware that road races are serious sporting events at all, as distinct from the casual exercise their parents or even grandparents might do on a Sunday morning. And it's not a case of the "completer" ethos being opposed to running for extrinsic rewards. Completers are not discouraged from flaunting their accomplishments as such. The emphasis on simply completing the race is really a matter of setting the bar far lower than than need be, encouraging new runners to settle for much less than they could accomplish, and failing in the process to offer them the deeper rewards associated with realizing one's full, long term athletic potential. To be critical of the completer movement in defense of running as a competitive sport is not to defend elitism against populism; quite the opposite. It is to affirm the potential of the average runner, regardless of her basic ability, to train longer and harder; and, in the process, to deepen her experience of running.

The association of running with the marathon has thus become more automatic in the wake of running's second boom simply because running is now more than ever associated with completing races, and the marathon is still the longest-- and therefore the most challenging-- race the average person has ever heard of. Increasingly, new runners are encouraged to think of their running journey as more or less complete once they have managed to get themselves from start to finish in marathon. All that remains is to repeat the accomplishment, and perhaps to seek out new and more stimulating venues in which to do so. I read the trend towards ultra running, Iron Man triathlon, and "adventure racing"-- still relatively small in comparison with the marathon at this point-- as an logical extension of the "completer" ethos. If running is now all about simply completing the longest distance possible, why stop at 42 kms?

The failure of this second running boom to produce a corresponding increase in elite and serious recreational performance is equally simple to understand. The prevalence of the completer ethos is far from the only reason fewer people now see running as a competitive sport. As referred to in earlier posts, there's also the effect of the contemporary youth development model (in North American at least)that has, I believe, contributed to a marked reduction in the numbers of serious adult elite and recreation runners. Nevertheless, the de-sportification of running that has occurred as a result of transformation of road races into exercises in mass fitness and community spiritedness, aided by the "learn to run" business, has, over a number of years, contributed to the decline of serious competitive running in places where this phenomenon has been most pronounced. These drivers of running's second boom have not necessarily reduced the numbers of serious runners in absolute terms, but they explain why running as a sport has failed to thrive in proportion to the sheer volume of new participants.

Finally, what about the question of whether or not all distance runners should, as a matter of course, aim to run a marathon at some point in their careers? Is the average person, after all, completely wrong in assuming that long distance running and the marathon are synonymous? If a runner is only interested in having a quick and conversation-stopping answer to the question/challenge referred to in the title of this post, then I would say: yes, do 3 or 4 longer runs, enter a race, get yourself through it in one piece, and move on. If, on the other hand, a runner is fine with looking like a failure in the eyes of his or her non-running family and work associates, and is content to be the best possible shorter distance runner he/she can be, then I would say not to bother. For those runners intrigued by the idea of attempting a marathon, I would offer the following advice. Assess your aptitude for this longest of serious racing distances by gauging your body's response to longer, easy runs. If you find runs of 2 hour plus generally disagreeable, either because they make you excessively sore or because they significantly impair your ability to complete your other workouts at a reasonable level, then attempting a marathon build-up and race may not be for you in the long run. Not every runner's body is suited to the marathon, just as not every runner's body is suited to the 100 meters. Approached seriously, the marathon is an extreme event, and only those with high aptitude for handling its special rigors have a great likelihood of success. And when the risks of failure are not only a disastrous race day performance, but weeks of fatigue, soreness to the point of injury, and generally un-enjoyable daily running, then the decision to attempt a marathon should not be taken lightly, even by those who have enjoyed great success at intermediate distances. Finally, even for those with obvious aptitude, I would not recommend attempting a marathon until the 2nd of 3rd year of serious training for road racing, and not before the age of 22.

Without a doubt, training for and racing the marathon is a classic test of the distance runner's mental and physical wherewithal. And, when it goes according to plan, there is perhaps no greater sense of accomplishment than crossing the line in a marathon race, considering the sheer number of variables to be successfully managed. The pursuit of this special high, however, is never worth the cost of destroying one's enjoyment of training for and racing distances for which one might be better suited. While possessed of a special aura and cache, the marathon is, nevertheless, and from the point of view of the running body, simply another road race. And, in the end, it remains just as significant an accomplishment-- arguably an even greater and more satisfying accomplishment-- to perform consistently well for a number of years at the shorter distances than it is to claim one or two great marathon successes, particularly if the price paid is a body no longer able to enjoy the simple pleasure of daily running.

Wednesday, 1 July 2009

Daniels Primer #4 (and more): What is a "Tempo" Run?

When I first encountered the work of Jack Daniels, in the form of the first edition of his now famous Daniels' Running Formula,the "ingredient" I found most interesting, and initially the most useful, was his "tempo" or "t-pace" run. For years, I had been doing harder, sustained runs of 6-8k, which I referred to as "tempo" runs; but, I had little idea of how, precisely, these were best approached, and I had an even dimmer understanding of how they were supposed to make me a better runner, beyond the psychological dimension of preparing me to concentrate, and hurt, for longer than time it took me to run 400m to 2k intervals that were the main staples of my training at the time. Without this basic understanding, I usually approached these runs as train-through time trials. Indeed, I hit some prodigious speeds in these sessions-- sometimes as fast as 2:55/km for as far as 8k. Because I attacked these runs with such ferocity, I was never been able to do them more than once every 10-14 days, and I gave them up entirely during the main racing seasons. Through Daniels, I was to learn a whole different approach to the sustained, faster-paced run; one that helped add several more good years to my open racing career, I am convinced.

With the help of Daniels, I was to put the "tempo" back in my tempo runs, which was ultimately to make all the difference.

As readers of this blog (or of Daniels himself) will know, the secret of Daniels' famous "formula" is his careful delineation of a series of training paces corresponding to various percentages of a given athlete's velocity at maximum oxygen uptake (different from a standard maximum volume of oxygen uptake, or "V02 max", which is a measure of the amount of oxygen an athlete can take in divided by his/her body weight). In his lab studies, Daniels observed that athletes could typically sustain their velocity at maximum oxygen uptake for an average of about 12mins, or approximately the time it takes to race 3 to 5kms, after which they would begin to slow dramatically, with associated increased levels of lactic acid in the muscles (I say associated because it remains unclear as to the actual role, if any, of lactic acid accumulation in causing an athlete to lose velocity when they typically do). Daniels also discovered that this velocity at V02 max was a very reliable guide to an athlete's performance at distances longer than 5k-- that it tended to be a kind of universal measure of a distance runner's basic ability.

As coaches had discovered in early part of the last century, running at or close to this speed ("racing speed") enabled a distance runner to become faster over time. As with lifting progressively heavier weights to increase muscular strength and power, running at speeds close to what Daniels was to call max V02 velocity provoked an over-compensation effect (a.k.a. a training effect) which, over time, increased an athlete's velocity at V02 max and improved his overall distance running performance. Theoretically, the more running an athlete could do at his V02 max velocity, the faster runner he would become. The catch, however, as Daniels and the other coaches of his era had begun to discover, was that the ability of an athlete to perform bouts of running at V02 max tended to be rather strictly circumscribed; in short, runners tended to become excessively tired and mentally stressed if they attempted to perform more than a given amount of work at this effort level. Innovative coaches, therefore, began to experiment with having athletes complete runs of longer (often many times longer) than the 12 mins they could run at maximum aerobic velocity, but at speeds much slower than this speed, which they sometimes referred to as "recovery" runs. And occasionally, depending on an athlete's racing specialty, coaches prescribed much shorter and faster runs with substantial recovery periods. Over time, many coaches began to observe that these sub- and super- maximum speeds seemed to have their own somewhat independent effect on an athlete's max aerobic speed. Coaches operating on the basis of training principles developed by the great Arthur Lydiard, for instance, observed that very long bouts of easy running, in the almost complete absence of V02 max paced running, could improve an athlete's speed at V02 max.

Daniels' "running formula" appears, as I have suggested, as an attempt to make systematic our use of these various super- and sub-maximal running paces by relating them to the physiologically adaptive responses they provoke, and by offering a practical method determining them for each athlete (his "VDOT" system). Daniels "threshold" or "T"-pace is located precisely at the transition from "easy" running, in which no lactic acid accumulation occurs in the muscles, and V02 max velocity, in which lactic acid accumulation begins to steadily increase. The training effect of running at this pace for periods of 20 to 60mins (although usually no more than 40mins is possible in a non-racing situation) is, according to Daniels, a tendency to increase physiological efficiency, or the body's ability to utilize oxygen, which is shown to have a knock-on effect in terms increasing velocity a V02 max. It is this physiological efficiency, according to Daniels, that helps explain how a distance runner can become faster over time without increasing his V02 max, or why runners with lower V02 max readings can quite often out-race runners with higher measures.

In the lab, Daniels observed that rested athletes could typically maintain this "threshold" pace for about 60mins, meaning that it correlated with race paces for distances of 13-20kms, depending on the speed of the athlete. In his own coaching practice, Daniels tended to prescribe sessions of "t-pace" running lasting at least 20mins and as long as 40mins once or twice a week, with further bouts inserted into specialized sessions for marathoners.

Having more or less understood how to use his other prescribed paces in my training, it was Daniels suggestion that sustained runs at as much as 15 seconds per mile slower and up to 30% further than I had be doing my own "tempo" sessions that stood out most for me upon discovering his book. This revelation also set me to thinking about my earlier transitional years-- from middle distance to long distance runner. It occurred to me that at various points in my career, such as during my summer of discontent following my dismal final year of high school, I had probably inadvertently done sizable chunks of my "easy" runs at close to what Daniels was calling "threshold" pace. In fact, whenever I had gone more than a week or two without doing structured workouts-- either during break periods or when returning from injury-- I would tend to gravitate to this pace at the end of my runs at least 3-4 times per week (without the stress of regular workouts, I tended to like to run fast much of the time). I had, I figured, probably already been benefiting from this kind of running; indeed, it probably figured fairly prominently in my becoming a long distance specialist in the first place.

All it took from here was to formalize my heretofore informal practice of occasionally running 20-40mins "steady" (the word that appears in my old training logs to describe this kind of effort) by adding it into to my cycle on a regular basis. This I began to do in my early 30s, at which point I noticed an improvement in my consistency in workouts as well as a feeling of greater mastery at racing distances 10k and longer. In addition to the physiological benefits I began to enjoy from slowing down and lengthening my regular my tempo runs, as well as doing them more frequently, I improved my ability to relax, concentrate, and control my pace in races lasting the typical duration of these sessions. As a coach, I have seen this kind of running, once mastered, work wonders in improving my athletes' performances at distances 5k and longer. So important and useful have I found this kind of running that I have even incorporated it into my program for younger runners. (In the case of younger runners, however, the immediate "bang-for-the-buck" of tempo running is not as great as for older and more experienced runners, mainly because younger runners are not doing sufficient total weekly volumes to tackle tempo sessions of much longer than about 15mins-- nor should they. It is, however, important that young athletes see this kind of running as a part of the normal training regimen of the serious distance runner, and that they learn to do it properly. Another bout of hard, V02 max running will always improve the performance of young athletes in the short term; but, if they plan to progress beyond the age-class ranks, they will sooner or later have to learn to execute proper tempo sessions-- and I prefer sooner to later.)

I think tempo running remains the most important, yet most misunderstood, form of distance training there is. The most common mistake among athletes and coaches remains that of doing them as undeclared time trials rather than as strictly controlled sessions. Because of their typical length, tempo sessions can become counterproductive if performed at too high an effort on a regular basis. In the pursuit of precise effort management, it is also important to stage tempo sessions on relatively flat terrain with stable footing. It is simply not possible to zero-in on proper "threshold" pace if steep hills or poor footing cause the athlete to work either too hard or not hard enough in a tempo session. The best way of determining one's "t" pace remains to run a race on a flat, fast course lasting about 60mins and use that pace as an average. When this isn't possible, it works to run for 20mins at one's perceived threshold pace immediately followed by an all-out section of 1-2kms. An increase in pace of greater than about 15 secs per km means that the perceived pace is almost certainly too slow, and a failure to increase the pace by more than 5 secs means it is almost certainly too fast. It's also possible to use heart rate as a gauge of t-pace; but, since most people don't have measure of their true max heart rate, and because heart race can be affected by variables unrelated to one's running effort, caution is advised if adopting this approach. In the end, I encourage my athletes to develop an accurate feel for their correct t-pace, so that they can properly maintain this effort when course and weather conditions vary. A useful rule of thumb for monitoring t-pace is a variation of the old "talk-test" for determining easy run pace (i.e. on an easy run, one should be able to carry one a conversation without undue discomfort). During a t-pace sessions, one should be able to speak, albeit only in short sentences and with lots of "recovery". When supervising t-pace sessions, I like to check athlete's effort level by asking them a simple question within seconds of finishing their workout or section. If they can answer within about 5 seconds, they've probably nailed their pace pretty closely. Finally, a t-pace session does not have to consist of one single bout of running. It is equally effective--and even preferable in warmer weather, for example-- to run sections of 4 to 15mins split by short recoveries (about 60 secs per 5mins run).