Can You Get More For Less?

Posted on April 6, 2012 by DJ2

Today we discuss aerobic exercise. It makes sense that different exercise programs can give a person different fitness results, but which is more effective? Those selling their exercise equipment on daytime TV would have you believe that you can achieve amazing results (using their equipment, of course), with minimal effort. But what exactly happens to our body when we exercise, and are there any shortcuts?

Our body adapts to aerobic exercise in different ways:

  • Cardiac output is increased, meaning more blood is delivered to active muscles each heartbeat (so our heart rate at a given workload will decrease)
  • Blood plasma volume increases, which improves oxygen transport and temperature regulation
  • Oxygen extraction from the blood is more efficient
  • Breathing becomes less frequent, and more oxygen is extracted from the air in the lungs with each breath

There are also obvious changes to body composition and performance, and changes in the muscle. Muscle mass increases slightly, and the proportion of slow twitch muscle fibres increase. The number of capillaries in our muscles increase through use, to deliver oxygen to the muscle.

As you could have guessed from list above, our capacity to exercise is limited by our body’s ability to provide oxygen to the working muscles. In laboratory setting this is called a person’s VO2max, and is measured in millilitres of oxygen consumed, per kilogram of body mass, per minute of exercise (mL.kg-1.min-1). Many fitness tests performed in gyms or by personal trainers are indirect measures of this.

Most research suggests that the effectiveness of your exercise, similar to modern medicine, depends on the dose. The more you take, the more effect it will have (this is only true to a point – like medicines, take too much and you will suffer side effects… injury!).

A recent study examined the relationship between the amount and intensity of aerobic exercise performed to muscle capillary density, and reinforced this. Middle aged men were assigned to either a control group, or one of 3 exercise groups: 1) a high amount & high intensity group (running 32km per week at 65-80% of VO2max), low amount & high intensity (running 19km per week at 65-80% of VO2max), and low amount & moderate intensity (19km per week walking at 40-55% of VO2max).

The results reveal no shortcuts! The control group did not improve their fitness at all (no surprise). The low amount, moderate intensity group improved marginally, while the most improvement – you guessed it – was in the high amount, high intensity group. Capillary density improved by a similar amount in all 3 exercising conditions. The authors concluded that capillary density changes with a relatively small dose of exercise, while change to our fitness level (and the associated performance increase) requires more.

There is a well-established link between the amount of exercise performed, the intensity of exercise, and the results that are possible (whether the target is fitness or weight loss). It is clear that the effort you put into an exercise program directly correlates with what you get out of it.

Again, there are no short cuts. Anyone who tells you anything different is either ignorant, or lying. While there are differences between the different forms of aerobic exercise (jogging, cycling, swimming, etc.) in terms of fitness benefit, the rules are the same. Work harder, for longer, for a better result.

References:

  1. Duscha, R.D., Annex, B.H., Johnson, J.L., Huffman, K., Houmard, J., & Kraus, W.E. (2012). Exercise Dose Response in Muscle, International Journal of Sports Medicine, 33, 218-223.
  2. McArdle, W.D., Katch, F.I., & Katch, V.L. (2010) Exercise physiology: nutrition, energy, and human performance. Baltimore, Maryland: Lippincott Williams & Wilkins.
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Steve Hooker’s Rough Road to London

Posted on February 26, 2012 by DJ2

Hooker celebrates gold at the 2009 World Championships

Pole vaulter Steve Hooker is one of my favourite athletes. He is a likeable bloke, he seems to take a lot of satisfaction and enjoyment out of his sport, and is gracious regardless of whether he places first or last. It has been disappointing to see his form unravel over the last few months, and I thought it would be interesting to discuss the possible reasons why from a sports psychology persepective.

Hooker had gone from strength to strength over the last few years. From 2005 to 2009 his best jumps were 5.87m, 5.96m, 5.91m, 6.00m, and 6.06m. He is now the second greatest pole vaulter of all time, behind only Sergey Bubka.

After a gold medal at the 2006 Commonwealth Games and a World Cup win in the same year, he followed up with an Olympic gold in 2008. But Hooker’s finest moment came during the 2009 world championships in Berlin. Carrying a thigh injury that severely limited his ability to jump, Hooker scraped into the final. It was during this final that his poise and self-confidence came to the fore. He sat back and watched his opponents take all their jumps, knowing that his injury would allow him only one jump at full strength (and a painful one at that). He then cleared 5.90m to win, in a performance that will go down as one  of the greatest ever performances by an Australian athlete. In my opinion, THE greatest.

Following that he won the world indoor title with a jump on 6.01m in 2010, but then things started to unravel. He recorded no successful jumps during Diamond League events in Shanghai and Oslo, and also failed to jump at the world championships in Seoul in 2011.

Though we can only guess at the exact reasons, Hooker’s technique has unravelled to the point that he often does not have the confidence to attempt a jump with a full run up at training, let alone in front of a crowd during competition. What was a skill that he could perform almost without thinking has become extremely stressful and complex.

When someone is attempting to perform a skill that is new to them, or they are not comfortable with, it takes a large amount of conscious thought. Competitive situations can be very stressful, due to the complex nature of the task, and the added pressure of spectators or other competitors. This level of stress can interfere with the performance of the task. In the case of pole vault, this may result in the end of the pole moving excessively during the run up, or effect the timing of movements involved in the jump.

On the other hand, a certain amount of stress can be beneficial to performance. It can result in heightened alertness, quicker reaction speed, and improved strength and speed. When expressed as a graph, we come up with the stress performance curve:

In the early part of the graph you can see a positive relationship between stress and performance, before reaching optimal performance at the peak of the curve. After that point, excessive stress begins to interfere with the smooth performance of the task, and results suffer. What is the optimal amount of stress? That depends on the person. Some athletes perform at their best when they are relaxed and calm during a game, while others feel the need to rant, rave, and punch walls. Others need to be challenged by a coach, an opponent, or the media before they perform to their potential. The peak of the stress-performance curve shifts to reflect this.

No matter where in this spectrum Hooker feels he performs at his best, it is clear that when competing he has left the area of the curve that produces his best performances. It will be interesting to see in the next 6 months how his coaches go about managing this, and rebuilding his technique and confidence. Their first step has been to limit the amount of information or feedback Hooker is being provided with, and his coach (Alex Parnov) will be the conduit for this. By doing this they are hoping that he can be more relaxed, with fewer distractions, and his training performance will improve. I’ve got my fingers  crossed – I would love to see him perform well in London.

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Crunch Your Way to a Flatter Stomach?

Posted on February 3, 2012 by DJ2

Abdominal obesity is a huge issue (pun intended) in western countries where the calorie content of many foods has increased, and exercise levels decreased over recent years. While I’m sure I don’t have to go through all the risks associated with obesity in general, abdominal body fat in particular results in an increased risk of heart disease and type II diabetes. In addition to health concerns, many people with concerns about body image will specifically mention their stomachs when talking to fitness professionals about weight loss. This means there is a potential market for anyone promising to flatten a stomach or two!

One result of the obesity epidemic is a large number of weight loss programs and products, with varying effectiveness. Some of these make wildly extravagant claims, and many don’t work! One of the recurring myths that has made millions of dollars for snake oil salesmen is the concept of spot reduction. This is the idea that performing exercise with a certain part of the body (such as abdominal crunches), will result in fat loss in that same body part (in this case meaning a flatter stomach).

This has been proved to be incorrect repeatedly over the years. Just as a person cannot choose where body fat is deposited, they also cannot chose where they lose this body fat from. Though there are individual differences, women will be more likely to accumulate fat in the hips, thighs, and arms as they gain weight, men will accumulate fat around the torso. There is also a clear relationship between the volume and intensity of exercise a person performs, and the amount of weight they can lose. This is something not discussed on TV infomercials.

For every fitness professional that tells people the truth about what a person can expect from their exercise routine, there are many others who tell them what they want to here. Who wants to hear ‘Sure, I can help you lose weight, but you will have to work bloody hard, and make plenty of sacrifices,’ when someone else is saying ‘just 10 minutes a day for a
flatter stomach’?

Some fresh research has examined this myth which confirms previous research into the concept. Researchers from several US universities performed a randomized control trial on 24 healthy, sedentary subjects. They excluded the physically active and those whose weight was fluctuating. The subjects were divided into two groups: they either remained sedentary (the control group), or performed an abdominal exercise program to be performed 5 days per week for 6 weeks. There was no other change to exercise levels, and diet was kept constant for both groups.

The exercise program took about 15 minutes to complete, including a gentle warm up and various crunches and abdominal rotation exercises. Compliance to the exercise program was nearly 100%. Both at the beginning and end of the study they were no differences in the two groups in three measures of body fat: 1) total body fat % (measured by the gold standard DEXA scan), 2) skinfolds, or 3) waist circumference.

The only notable difference between the groups was in abdominal endurance, when the exercising group was able to perform better in a test where they completed sit ups for 1 minute. This is not a major surprise, given they had been performing abdominal exercise 5 days a week for the last 6 weeks!

This brings to three the number of studies I have read that discredit spot reduction. I have yet to see convincing research in favour of the concept. But it does not stop personal trainers, gyms, and those selling exercise equipment on daytime TV (think the Ab-Roller or the Ab King Pro) from perpetuating the myth. It confirms that those who spruik products or programs claiming to spot reduce abdominal body fat are either ignorant of the evidence, or choose to ignore it. Either way, they are not to be trusted with exercise advice.

Reference:

  • Vispute, S.S., Smith, J.D., LeCheminant, J.D., & Hurley, K.S. (2011). The effect of abdominal exercise on abdominal fat. The Journal of Strength & Conditioning Research, 25(9), 2559-64.
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Tebow, Statistics, and the Second Season Slump

Posted on January 15, 2012 by DJ2

When the coaches at the Australian football club I work for start talking to me about Tim Tebow and the fortunes of the Denver Broncos, I know something strange is happening. It is not often that NFL news makes for water cooler conversation in Australia! Here’s some quick background in case you don’t know what I’m talking about.

Tebow attracts attention for a variety of reasons. Firstly, he was a standout college football player before turning professional. Secondly, he is very religious, and takes every opportunity in interviews and press conferences to discuss his religion. Thirdly, after a good passage of play, he has a habit of conspicuously dropping to one knee and bowing his head in prayer (leading to the internet meme of “Tebowing”). Finally, until the Broncos’ season ended in the playoffs last weekend against the New England Patriots, he was making a habit out of winning games with a late comeback, and led his team to an unlikely playoffs berth.

The American sports media has given him enormous amounts of credit for leading his team to wins in spite of seemingly unimpressive performances at the professional level – that is, he seems to win games more often than he should. In 2010 Tebow completed 50% of his passes (the top quarterbacks complete more than 65%), threw 5 touchdowns and 3 interceptions, and won only one of the three games he started.

In 2011 he started 13 games (including 2 playoff games), completed 45% of his passes (last out of 32 starting quarterbacks), and threw 14 touchdowns and 6 interceptions. These stats are not the sign of a great quarterback. But the Broncos amazingly won 8 of these games (4 of them in overtime), despite losing 4 out of 5 with a different quarterback at the beginning of the season.

Is this an example of the ‘intangibles’ that coaches talk about: innate football skills and knowledge that cannot be measured directly, but can still influence the outcome of a game? Possibly. Is it God helping Tebow win so he can spread His word? Probably not. Is it a statistical anomaly that will soon even out? Much more likely. If we can exclude the possibility of direct intervention by Tebow’s deity (this is something I may discuss in a future post) then his habit of winning in spite of poor performances for most of the game is a quirk of the numbers, which will correct itself the longer he plays.

The name for this phenomenon is ‘regression towards the mean,’ recognized in sporting circles as the ‘second season slump’ or ‘sophomore syndrome.’ This means that if a variable is extreme at first (such as Tebow’s record of wins as a starter), it will move closer to the average with more measurement. In this case, the more Tebow plays, the more his teams’ win/loss record will begin to reflect his true ability, and winning and losing streaks (often due to variables out of his control) start to even out.

The second season slump is often attributed to opposition teams and coaches having more access to video footage and information about the young player. This allows them to implement better game plans to contain them. This is an important factor, and how the player performs in subsequent seasons against well prepared opposition could be a more accurate reflection of their ability.

The opposite can also occur. A player can perform very poorly at the start of their career in spite of obvious talent, and then improve significantly the more they play. Experience and coaching will be responsible for a large part of this improvement, but again a large sample size gives us a better insight into a player’s true abilities.

Current Green Bay Packers quarterback (and 2011 Superbowl MVP) Aaron Rodgers is an example of this. After playing in 5 games as a back-up to Brett Favre in 2005 and 2006 he had a completion percentage of 48%. He is now recognized as one of the best players in the NFL, and has a completion percentage about 65%. He led the Packers to 15 consecutive wins this year, with the possibility of a second Superbowl win in the next few weeks.

The career of cricketer Brett Lee is another example of regression towards the mean. In his first three Test series against India, New Zealand, and the West Indies (1999-2001) Lee took 42 wickets in 7 Tests, at the astonishing average of 16.05. By the end of his career, he had taken 310 wickets at an average of 30.81 – an impressive career, but not world class. By comparison, Glenn McGrath, one of the most successful fast bowlers in history (and a contemporary of Lee’s) took 563 Test wickets at an average of 21.64. It is possible that injuries hampered Lee’s ability to maintain his extraordinary start, but his career as a whole is a better reflection of his abilities than his first 7 Tests.

I know it is strange to be discussing the NFL and cricket in the same article, but this helps to illustrate my point. Regardless of the sport, regardless of the player, every now and then they go on a winning streak, or string together great performances. Sometimes this streak is at the beginning of their career. This is true of Tebow. While he has enjoyed success to this point and had some remarkable wins, keep in mind that at the end of his career his record may be very different. Religious types and football analysts who have been getting excited by his success to date should keep this in mind.

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Compression and Performance

Posted on December 26, 2011 by DJ2

In the last five or six years there has been a trend towards the use of compression garments by sportspeople of all levels. What began when Skins first emerged onto the market has expanded rapidly, with major sporting brands selling their own compression garments, and numerous other smaller businesses also taking market share.

The manufacturers of these products make some interesting claims in their advertising. The Skins website claims that their garments ‘take into account compression levels needed to increase oxygen delivery to active muscles while in motion.’ This results in ‘more oxygen delivery and reduced lactic acid build up.’ Other manufacturers also claim to reduce the amount of vibration in active muscles, and that ‘you go harder, for longer, and recover faster.’ Double entendre aside, today we discuss exactly what a compression garment is, and how/if it works to improve athletic performance.

Compression garments are elastic, moulded suits covering all or part of the body. They are normally sold as shirts (either long or short sleeve) or tights. They have a compression gradient in which forces are greater at the end of each limb than at the torso.

Despite all the claims of manufacturers about the precise design and research into their compression gradients, it is impossible to accurately predict the amount of pressure a garment will apply. The equation used for predicting the amount of pressure produced by a garment is a modified version of the LaPlace equation. However, this only applies at the moment the garment is worn for the first time (and even then, only if the assumptions the manufacturer makes about the length and width of a person’s limb is correct). This equation is shown below:

After this point in time the fabric begins to fatigue, and will minutely deform. This does not occur in a linear fashion, so it is impossible to accurately predict the rate of fatigue of the garment. Companies selling these products generally recommend replacing them regularly, though the appropriate length of time is anyone’s guess. But despite this, can they help to improve a person’s athletic performance? The short answer is ‘maybe, sometimes.’

Doan et al (2003) performed a study on 20 division one college track athletes, wearing custom fitted compression shorts, or American football shorts as a control. It is important to note that the garments were fitted based on participants’ waist, hip, thigh, and knee measurement. They were not off the shelf products. This is a level of fit not available to the public. When the participants were wearing the garments there was some increase in vertical jump height, and reduced muscle oscillation on landing. There was no change, however, in 60m sprint performance.

Duffield & Portus (2007) examined the effect of 3 brands of garment: Skins, UnderArmor, and Adidas. Their participants were 10 club cricketers. Participants wore all 3 garments on 3 different testing days, as well as a control condition in which they only wore normal cricket clothing.

They performed a 30m repeated sprint protocol, interspersed with cricket related throwing tasks. They found no difference in throwing difference, accuracy, or sprint performance. They also found no difference between any of the garments or the control condition in heart rate, blood lactate levels (a marker of fatigue), or oxygen saturation.

Houghton, Dawson, & Maloney (2007) studied 10 amateur hockey players wearing either normal hockey clothing or Skins short sleeve top and shorts in a 60min exercise protocol consisting of walking, sprinting, and jogging, with a break every 15min. Sprint times, rate of perceived exertion, and heart rate all increased significantly with fatigue, but there was no difference between trials. Total distance covered did not change significantly. Although skin temperature increased, core temperature did not. The authors concluded that compression garments can be used in cooler conditions as a base layer, but did not improve performance.

To date, increased skin temperature is the only consistent finding of the research, being reported by Doan et al (2003), Duffield and Portus (2007), and Houghton, Dawson, & Maloney (2007). Some studies have shown an improvement in sprint performance when wearing compression garments (Higgins, Naughton, & Burgess, 2009), though small. Most studies have not replicated this though.

The evidence is clearer in supporting the use of compression garments in recovery. More research must be done on their effect on power, and muscle oscillation on landing. But the
claims of the manufacturers are well in excess of the evidence at the moment. My advice for sportspeople for using compression garments is:

  • Effectiveness depends very much on the fit of the garment
  • Replace your compression garments regularly
  • Any performance benefit is small, so for the recreational or amateur athlete this will be negligible compared to the benefits from effective training, sport specific warm ups, and good nutritional strategies
  • Compression garments can be used to improve comfort in cold conditions

If when training or playing you feel more comfortable in your compression garments, then I would encourage you to continue to use them. If you are not currently using them, or are concerned by the cost, you will not be at any disadvantage by not wearing them. If it does turn out that they have a performance benefit, it will most likely be in power events, and not endurance sports.

  1.  Doan, B.K., Kwon, Y., Newton, R.U., Shim, J., Popper, E.M., Rogers, R.A., et al. (2003). Evaluation of a lower body compression garment. Journal of Sports Sciences, 21, 601-610.
  2. Duffield, R.D., and Portus, M. (2007). Comparison of three types of full-body compression garments on throwing and repeat-sprint performance in cricket players. British Journal of Sports Medicine, 41, 409-414.
  3. Higgins, T., Naughton, G.A., and Burgess, D. (2009). Effects of wearing compression garments on physiological and performance measures in a simulated game-specific circuit for netball. Journal of Science and Medicine in Sport, 12, 223-226
  4. Houghton, L.A., Dawson, B., and Maloney, S.K. (2009). Effects of wearing compression garments on thermoregulation during simulated team sport activity in temperate environmental conditions. Journal of Science and Medicine in Sport, 12, 303-309.
  5. Troynikov, O., Ashayeri, E., Burton, M., Subic, A., Alam, F., and Marteau, S. (2010). Factors influencing the effectiveness of compression garments used in sports. Procedia Engineering, 2, 2823-2829.
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Playing Your Natural Game

Posted on December 11, 2011 by DJ2

While preparing this blog for the first post (which will now be the second post) I was keeping half an eye on the Australia – New Zealand cricket Test on TV. I am well aware that this attempt at multitasking makes me much less productive, but I find ignoring cricket pretty much impossible! As I was pretending to work and watching some highlights from earlier in the match, I noticed that Brad Haddin had been dismissed cheaply again, and I was reminded of much of the media coverage surrounding Haddin recently. Specifically, his oft-stated desire to “play his natural game.” This got me thinking… what is a player’s “natural game?” Why is it so desirable? Why is it a term bandied about so much in cricket?

Although this could be a lengthy discussion by itself, I think that to “play your natural game” in batting terms means to play those shots that you are most comfortable/effective at playing. Various players are predominantly front foot or back foot players, others enjoy horizontal bat strokes, while yet others are more comfortable with a straight bat. Some players score mostly on the leg side, others the off side. It is these preferences or strengths that will determine where a player sits in a batting order.

However, it is not always as simple as that. Weather conditions will affect the movement of the ball in the air, and the pitch will affect the amount of pace and bounce the ball has when it reaches the batsmen. The opposition may bowl a variety of deliveries depending on these conditions, the state of the ball, field placements, the state of the match, and the analysis that they have done of the batsmen prior to the match. This means that there are times when your “natural game” is the ideal way to play at that given time. More likely is that judgements need to be made on what shots should be played, and which are too risky.

An aspect of Haddin’s natural game is that he plays aggressively, and looks to play shots and score runs quickly, rather than settle in for a long innings. This was also a defining feature of Australian teams of the last 15 years or so – Matthew Hayden is an obvious example of someone who played aggressively regardless of the circumstances for most of his career. Adam Gilchrist is the definitive keeper-batsmen in world cricket, and another who scored quickly as a general rule. Australian test teams of this era were nearly invincible, and playing an aggressive brand of cricket was easy when a player knew that everyone else in the team was bound to score runs should he fail. But this has not been the case in the last 3-4 years.

The most reliable aspect of the media coverage of this Australian cricket team is that at least once a week someone will declare that they will, or someone else must, “play their natural game.” On November 10th, during the Australia-South Africa Test at Newlands, the headline in the Sydney Morning Herald read:

‘I want Haddin to play his natural game’: Clarke.

Australian captain Michael Clarke says he’s happy for struggling wicketkeeper Brad Haddin to continue playing ambitiously in his search for top form… Clarke said he isn’t worried about Haddin and doesn’t want him to change his approach. ”He’ll be disappointed that he hasn’t made more runs, but he’s a match-winner and a positive player. He’s going to play his shots and I don’t have a problem with that,” said Clarke. ”I’d rather see guys get out playing their natural game, than being a little bit timid.”

 What Clarke has said here is if Haddin is going to get out quickly, he would rather he do it playing positively and aggressively, rather than getting out while not attempting to score runs. But Clarke seems to be assuming here that there is no merit in beginning slowly, becoming accustomed to the movement of the ball off the pitch, the speed of the bowlers, and the placement of fieldsmen. Or that when wickets are falling quickly and the bowling team has momentum and confidence, that there is no benefit in occupying the crease and slowing down the pace of the game.

In that Test Australia was scuttled for a total of 47 runs in the second innings – one of the worst performances ever by an Australian team, against a strong South African outfit. Haddin did poorly in the match, contributing 5 & 0. In Australia’s capitulation, he was out cheaply playing an aggressive shot when the score was 5/18. On November 14th ESPN Cricinfo quoted Haddin as saying: “It’s important for everyone to play their natural game. There are moments in the game when you have to assess situations and that’s something I didn’t do great the other day. But the bottom line is you have to be true to yourself and your team-mates and play the way that’s got you here.”

I find this quote a little confusing, because although Haddin seems to accept that there are times when it is necessary to adjust the way he plays, he refuses to do so. Given the hours of preparation that go into elite sport these days, it seems implausible that a team would go into a game with a plan of doing the same thing they always do. This would mean hours of video analysis, training, meetings, and scouting of the opposition would be ignored. That a coach paid hundreds of thousands of dollars a year would be reduced to the role of a spectator while his team “played their natural game.” While some pundits would suggest that this is exactly what happened in all-conquering Australian teams of previous years (think the Steve Waugh/John Buchanan years), in most professional sporting teams this is a short cut to poor performances.

There are also frequent examples of players who have had to modify or reinvent their game in order to be successful at the highest level. Steve Waugh was in and out of the Australian cricket team in the 1980s until he stopped playing some of the attacking shots that had been getting him out cheaply, and went on to become a great of the game. Matthew Hayden prolonged is career by a year or more by playing a more conservative brand of cricket, and occupying the crease for long periods as an opener.

Success in sport is largely determined by an individual’s (or a team’s) ability to critically assess their performance, and make adjustments as necessary to improve. It is also necessary to assess the strengths and weaknesses of the opposition, and adjust game plans to reflect this. Even the most dominant teams on the sporting landscape today (the All Blacks in rugby union, the Green Bay Packers in the NFL, and the Brisbane Roar in the A League spring to mind straight away) make adjustments to their style of play to reflect their opposition. Playing their “natural game,” and ignoring these opportunities for adjustment and improvement indicate either arrogance, an inability to honestly reflect on their performance, or a poor assessment of risk. Or it could just be something to say during a press conference! Regardless of the reason, it is a phrase I would love to see less of in the media.

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