Category: News

How often does one make full revolutions of the cranks in a DH race and during practice? Well that depends; course type, terrain, climatic and environmental conditions, gear ratios etc…

What is a certainty though is that pedaling during DH racing is intermittent i.e. “occurring at irregular intervals; not continuous or steady”. While we ride DH on a bicycle, two wheels, cranks, chain etc… unlike our roadie or XC cousins, quite often the main means of locomotion for the DH athlete/rider isn’t application of force on the pedals but gravity! Having said that tough, what is also certain is that pedaling can be a determinant of performance and results.

So it goes without saying that understanding the energetics (how energy is supplied) for these intermittent repeat sprint bouts is quite important when looking to prepare yourself to meet the varied physical demands of DH. Interestingly repeat sprint ability is something that in the last decade has been study a great deal in the laboratory by many well respected sports scientists. Even more interesting is that many of the Repeat sprint Ability (RSA) testing protocols used in these studies mimic the demands of DH specific pedaling dynamics closer than they do the sports they are primarily testing/researching for (field and court sports, soccer, basketball, tennis, ARF, hurling etc…).

Many of the studies used a 6 sec “MAX” sprint interspersed by 24 to 30 sec of stationary/passive recovery. So if we look at a power metre graph from a fairly typical DH run we can see the similarities.

Similarities there may be but on the other hand there are some key differences and this is where we will start our wee journey into hopefully understanding the Repeat Sprint Pedaling Demands of DH a little bit better and then go on to talk about the key areas we need to train to improve our RSPA – Repeat Sprint-Pedaling Ability!

What are you looking for?

As a DHer you’re looking for two key things to ensure optimal pedaling performance. 1)Achieving a high peak power output, 2)minimising the reduction in this peak power output over repeated sprints. In other words reducing your fatigueability over many repeat efforts on the pedals in one run. In short this IS Repeat Sprint Pedaling Ability.

The exact causes of fatigue during repeat sprints is the topic of hot debate and much research but having a clear grasp of the most likely and/or proven factors in RS fatigue is the first step in understanding how to train effectively to increase your potential to create repeat power!

Back to Basics

Before we get to a point where we can understand the factors that create fatigue and limit RSPA you’ve got to understand the relative contributions of each one of our three energy systems to “all-out” riding during a DH run.

The 3 energy systems are distinct but closely integrated, they operate together  in a sequential but overlapping manner to supply working muscle with the energy it demands. The energy systems are split into 2 categories. Aerobic (with oxygen) and Anaerobic (without oxygen). The Anaerobic systems are subdivided into ATP-PCr and Anaerobic Glycolytic (the infamous anaerobic lactic system).

The ATP – PCr system is the most direct supplier of energy to muscle. As a tiny amount of stored ATP (our energy currency) exists in skeletal muscle along side stores of the high energy phosphate Phosphocreatine (PCr), between the instant utilisation of ATP and the very fast breakdown of PCr large amounts of energy can be supplied to working muscle very quickly for a duration of up to 8 seconds give or take! This is why Sprint 1 of a DH race is the most powerful. Maximum stores of PCr, minimum fatigue, maximum neural drive!

The second anaerobic system is the glycolytic system, this is simply the break down of stored carbohydrate (glycogen) in the muscles with no oxygen. This is a fast supplier of energy as the reactions take place in the site where movement will be created, but it has it’s limitations as it creates many by-products that need to be shuttled away from the working muscles for movement to continue. The “lactic” system can provide energy for up to 75 secs but really beyond the 35 sec mark our next energy system, the Aerobic system, really kicks in.

Finally the aerobic system breaks down stores of fat and carbohydrate to produce ATP (our energy currency), this happens in the muscle but not directly at thesite of movement, so it’s not quite as “fast”. But if we are correctly warmed up then aerobic metabolism produces a large percentage of our energy for any “all-out” activity beyond the 75sec mark! And remember the average DH World Cup run is 225 to 275sec in duration.

How it fits into DH Specific RSPA?

Right so now that we have the dull stuff out of the way let’s get down to business. AS we could see in the power trace graph further up DH often requires a hard initial sprint out of the start gate, followed by repeat “all-out” efforts on the pedals at irregular intervals. You can have anything from 3-5 secs right up to minutes between pedaling efforts (ala Val di Sole). Usually though it’s pedaling bouts of 3-6 secs with gaps between of 10 – 25secs.

So most of the very good research out there points to 2 things, firstly the initial sprint performance is very important and that this initial sprint of 3-6 sec is fueled mainly by the ATP-PCr system. With gaps of 10-25sec between repeat efforts on the pedals it is again the ATP-PCr system that fuels the efforts but onl if your AEROBIC system is “fit” enough to replenishes your PCr stores, as it is solely the Aerobic system that replenishes your stocks of PCr! Finally once you get out to the 225 sec + mark in time it looks like the fittest athletes with the best RSPA rely heavily on the aerobic system to fuel these final sprints with the glycolytic system contributing only ¬8%!

Pie chart below showing what I’m talking about from the great review on the subject by Girard et al 2011 Sports Med 2011; 41 (8): 673-694

So things seem clear for now…right? The above test protocol was 10 X 6 sec sprints with 30 sec recovery between them, so not to dissimilar to the demands of DH pedaling….right? Well maybe it’s not that simple! The 30 sec recovery between the 6 sec effort sin the above study was total rest, stationary chill-out until your next 6 sec bout and that’s where the similarities with DH end!

Because as we all know between sprints on your DH bike there’s usually a whole lot happening, riding! Yep the main bulk of our performance and most certainly the main determinant of performance is actually riding your bike and riding it FAST. So how does that effect your RSPA? Well it’s something that has never been directly studied, but as a coach for many DH athletes it’s something I can certainly make some educated assumptions about!

What do we do?

Well basically you hang off the steed at a million clicks and try hit your lines? Well not quite but the demands of DH are pretty varied and as such are pretty complete. The basic goal is choosing the best, fastest line from A to B and executing the required techniques at the required time to make your lines and carry the required speed to have the fastest time! Simple!

But the energy demanded by riding as fast as possible from A to B is substantial. Especially when the terrain is rough, steep, fast and gnarly. The mix of isometric, eccentric and concentric muscular contractions, the fine and gross motor skills that executing a huge range of techniques requires is hugely energy hungry. Maintaining posture, exploding off jumps, hitting and skipping over huge holes, railing berms, climbing off-cambers and shredding turns all require energy to be produced by all 3 energy systems in unison by in time and intensity dependent amounts.

How riding affects pedaling?

No need to complicate the discussion really. The harder you ride the more intramuscular energy stores you’ll burn and the less likely you are to have re-synthesized even partial amounts of PCr for pedaling after the first sprint. But, the more skillful you are, the better your technique is and the less energy you expend while riding at optimal pace the more likely it is that you’ll still have adequate stores of ATP, PCr and muscle glycogen to fuel very rapid metabolic reactions to power short sprint efforts. Likewise as the muscles we use to maintain riding posture and execute techniques are not used in exactly the same way and with the same inter and intra-muscular co-ordination as during pedaling then we can assume that the more aerobically fit you are the more likely you are to re-synthesize stores of PCr that could be used for explosive pedaling actions.

It’s an interesting topic and something that warrants good research, we know that steep natural tracks are more physically demanding in their riding induced loads (Hurst, Swaern et.al 2013) than “bike-park” style tracks, but often steep natural tracks require little pedaling and certainly show few of the hallmarks of the demands of RSPA.

Course duration too will have a large effect on inter-relationship of the three energy systems and how your body chooses to supply the required metabolic energy to make the muscles contract in sequence for pedaling.

Alot of these “issues” presented have some pretty common sense, evidence backed answers. As we’ll see below.

How to ensure “RSPA” performance?

How to train for supreme RSPA performance? First identify the limiting factors, understand how to improve them then integrate the training.

One of my favourite quotes is “you can’t maintain what you don’t have”, basically looking to improve your sprint capacity or repeat sprint ability is pretty worthless if you can’t sprint in the first place. So training the mechanical factors like strength then power, intra muscular co-ordination, neural drive, fibre type, motor-unit recruitment etc… is key! These can be trained in the gym and on the bike. With the gym offering many benefits the bike does not.

Once mechanical power production is developed it needs to be supported by the metabolic processes, the energy systems and other factors such as enzyme activation and energy stores.

Training the aerobic system to it’s optimal state so re-synthesis of PCr is improved (Bishop, Girard et.al 2011), one study carried out in Norway ( Balsom et.al; Acta Physiol Scand 1994) showed large (11%+) improvements in RSA (again 10 X 6sec sprints) when participants where administered EPO, thus improving the oxygen carrying capacity of their blood and subsequently aerobic “fitness”. Like-wise similar RSA tests where participants have actively restricted blood flow (ischemia) to the legs their was a marked reduction in RSA performance over 10 sprints due to the inability of the aerobic system to re-synthesis PCr stores and actively provide energy for muscular contraction in it’s own right.

Starting training session in a fully fueled state so training “impulse” and signaling for a sprint session is at it’s highest.

Training to resist, buffer or better deal with metabolic by-products of high intensity exercise created by the Anaerobic Glycolytic system should also be considered, especially for mixed tracks that require a variety of riding styles or techniques and pedaling. The inorganic phosphates and general acidosis created by anaerobic glycolytic metabolism play havoc within muscle tissue and reduce the “excitability” of the muscles, reducing their contractile function and intra-muscular co-ordination, one of the main reasons why increases in fatigue causes crashes, falls, poor performance or that feeling of being a complete tool on the bike!

Improving your technique and skill on the bike will possibly lead to less energy expended for the same speed A to B and as such more potential energy available to fuel sprint pedaling performances and possibly more window for your aerobic system to re-synthesis PCr in the “pedaling muscles”.

Integrating any training you do to actually “work” on your race bike under conditions characteristic of the sport is also a crucial area often over-looked by many.

The importance of training the anaerobic glycolytic pathways of energy production for pedaling performance for DH is highly debatable. There certainly are specific courses (PMB, Canberra) where this type of training could be beneficial but much of the anaerobic fueled demands in DH are not pedaling induced, but riding induced.

Wrap Up

Much of the data, studies and evidence presented here comes from repeat pedaling tests, but designed by scientist looking into the demands of field and court based sports not MTB. So as such common-sense and experience based critical analysis should be applied to everything you read.

Are the pedaling bouts in DH repeat, sporadic and intermittent in nature? YES. Is each course equal? No. Do the demands on energy supply and change with the activity profile and riding dynamics of each individual course…absolutely! What does all that mean for the DHer looking to improve their performance on the pedals? Get strong, be fluid on the bike, relax, train all 3 energy systems but not all the time nor in equal amounts.

Every one has their own strengths and weaknesses. But with the huge variety in courses, pedaling demands and the ever changing environment (weather, altitude, courses etc..) you face as a DHer having a well tuned aerobic system and a big strength foundation will serve you very well. Couple that with good mobility, flexibility, adequate nutrition and characteristic training and you’ll be well on your way to pedaling well on your DH bike.

Below I’ve included a chart covering the main ways you can improve your RSPA. adapted from the fantastic work of Mladen Jovanovic @ www.complementarytraining.com

We could talk training methodology, influence of hostile environments (altitude) on RSPA, best practice during different stages of development, pedal type, tyre type, wind resistance etc… for days on end, so feel free to ask questions or create some discussion in the comment section.

Just always remember performance and fatigue are multi-factoral, so your training should reflect that. But you can’t train all factors all the time. So a good coach or clever head to plan your progressions in training is needed!

This is part 1 in a two part series, next up will be the pedaling demands of Enduro racing and how best to train for them!

Chris

It’s all about the junk in the trunk! Maybe a better way of looking at it is “their ain’t no position like the attack position”?

Posture is something your mother probably mentioned to you when you were (maybe you still are) a teenager. Well sadly for you it’s just as important on the bike as it is in daily life, in reality they are one and the same and that’s something I’ll talk about down below – awareness of daily postures.

So let’s get to business, the title says it all really, the posterior chain is something often refereed too, but seldom trained correctly and often neglected. What is it exactly? Well refer to exhibit 1 below. That’s right it’s the back side of your body from the erector-spinae right down to your Achilles tendon but  what we are going to focus in on a little more closely is the junk in your trunk…the gluteus maximus (there is a medius and minimus too), and the 3 muscles that make up the “hamstring” are our main hip extensors; i.e. they straighten your hip, think about going from seated to standing!

The real point of focus of this blog post though is the gluteus maximus ..why? Well simply put many downhillers and other gravity MTB riders I see are “quad-dominant”, they have over active hip-flexing muscles, poor overall hip mobility, weak abdominals and in some cases present with lower cross syndrome where the hip flexors are so tight they inhibit glute activation and subsequently the hamstring muscles and lower back have to take up the slack so to speak when extending the hip joint.

Why is that a problem I hear you ask, well long term it’s a recipe for disaster, from lower back pain to knee injuries and hamstring cramp and strains, having over active hip flexors and under used glutes leads to all those long term issues but in the more short term it basically means that you are not using your most power ful hip extensor! Which means 1) you won’t be pedaling anywhere near as powerfully or effectively as you could and 2) your posture, strength and overall technique on the bike in rough, steep or wild terrain will be severely hampered!

Simply NOT GOOD!

You see while the hamstring muscles (semitendinosus, semimembranosus and biceps femoris) all act to extended the hip they do so in a position specific manner. Depending on how flexed/bent your knee is the hamstring muscles have different roles and act in conjunction with our main hip extended the GLUTEUS maximus! The hamstrings hang off the pelvis and run to below the knee, as such they have a large role to play in knee flexion. The glutes however and specifically Glute Max are a one joint muscle, they hang of the top of your pelvis, lumbar spine and sacrum and attach at the femur. They are the King daddy of hip extension, power production and control! Once you master their correct function you’ll have nothing but fun and explosive playfulness on the bike! Don’t get me wrong the hamstrings have a pivotal role to play in keeping you “in posture” on the bike, especially when things get steep or sideways, but the glutes drive you back to “center” so to speak,

Attack Position

The glutes are such a key muscle in mountain bikers posture and “attack position” for a few reasons.  You’ll often see the most elite mountain bikers in a very relaxed and tall positon on the bike, even when things are getting wild..why? Tall means limited knee flexion, which in turn means limited activation of your quad muscles and hip flexors and thus less energy expended. The muscles that maintain this mix of dynamic and isometric contraction to keep you “tall” are the glutes and to a lesser extent the hamstrings and in gros the posterior chain!

Your torso should remain neutral and strong while your hips travel through a pretty limited range of motion of flexion and extension to maintain control and execute techniques over the wildest of terrain. So yet again we can see the importance of glute strength and control! The glutes are also the primary muscle that resists flexion of the knee and hip, so think about 20m of successive Les Gets size braking bumps or a WC DH course like Mont Sainte Anne, what’s going to help you maintain posture, vision, control and speed? That’s right GLUTEUS MAXIMUS!

But we ain’t finished their, Gluteus Maximus also has key role to play in stabilising the hip joint. So for example, like discussed above, if you have “lower crossed” syndrome or some similar issues you’ll often find that you have pain in the front of the groin. Making it feel tight and sore, normally most people will go to stretch their hip flexors when it reality it’s poor glute strength and control that is leading to your femoral head sliding forward in the hip socket and causing issues. Strong glutes actively “pull” the head of the femur back and stop this issue. Likewise strong glute max means you’ll feel stable and “solid” on the bike in critical “gnarly” situations. Your centre of gravity is more likely to be maintained if you have strong glutes.

Similarly if you want to bunny-hop or “explode” or pop off of a small jump, drop or roller you’ll need to actively extend the hip and drive your centre of mass forward. This is achieved by having powerful glute max.

Gravity’s effect on the hip joint is also quite profound, especially when we actively multiple gravity by hammering down a mountain side and hitting turns, drops and rock gardens. Simply maintaining an erect posture or re-finding the “attack position” regardless of how “tall” or extended yours is requires glute control and strength. If finding yourself lower and lower and further and further back as you descend or ride sounds like you, ending up with a low torso, flexed knees and hips over the rear axle all the time is “your thing” then it is pretty likely that you have some glute control/strength issues and likely are presenting with some of the issues of “lower crossed” syndrome.

Luckily for you guys though, I’m here to help. I’m going to walk you through a few simple steps and exercises you can incorporate into your strength training or general exercise routines to help establish glute strength and control as well as lumbo-pelvic control, abdominal strength and hip-hinge mastery! All of which are the key ingredients of what we want to start cooking up on the bike.

In clearer terms what we want is a Stable Core – Mobile Hips but Strong and balanced everything!

How To:

1. Stabilise

First stop is to learn to stabilise the core, use your breathing muscles correctly and work on rotating your pelvis posteriorly! Sounds complicated but it’s not. Use well know anti extension core moves like planks (focusing on squeezing your glutes) as well as using active stabilising moves like the half kneeling shoulder press with a glute activation.

The best place to start with stabilising though for most people is the “DeadBug”. This move although simple looking requires supreme core control as you bring upper and lower limbs through full range of motion. It’s the perfect place to start to get your lower back to relax, pelvis to rotate back and genrally deal with dysfunction before we go on to load up or deal directly with strengthening the glutes and mobilising the hips!

2.Mobilise

Moblity for the hips, glutes and posterior chain is built on a foundation of control…plain and simple. There is no need to mobilise if you can’t control movement.

There are an endless list of drills to do for hip mobility as well as specific glute and posterior chain stretches that may be needed for certain people. One of my favourite “combo” moves though works to stabilise and strengthen the glutes uni-laterally while mobilising the hips in a way that is very useful to mountain bikers (external rotation, think inside leg when cornering hard). This move is called the “Sweeper”. I’ll let the video do the explaining.

Next up in the mobilisng list is the hip hinge…this is crucial, absolutely crucial if you want to learn to use your glutes to their natural potential and certainly if you wish to go on to actively training the posterior chain for strength! Watch the video below to see more and the keen eye will see the similarities between the hip hinge and the normal “attack-position” you should have on your bike.

Learning to hinge your hips means moving your hips through a wide range of motion while the knees stay static or work through a very small ROM. Similar to what we want on the bike (although we are in a slight split-stance on the MTB)!

One of my favourite combo moves though that covers posterior chain control and overall strength is this:

3. Strengthen

The list here is deep! Real deep. The amount of quality exercises that exist to work the posterior chain and glutes is very wide ranging. The best way to approach it though is to start basic and work your way up to mre complete or complex movements before you even worry about load. Once you’ve mastered the skill aspect of strength and gained the benefits there in terms of your glute strength then you can think about going back and loading up the more basic or complex moves with external weight!

The progression for Point1 athletes often goes something like this…

Bridging

Hinging/Swings

Light Single Leg

Bi-lateral – like Deadlifts

Heavy Single Leg/GHR’s

Partial Oly-Lifts or Explosive work

Now while that is the usual progression that doesn’t mean we don’t frequently regress the moves or mix and match as we need. Especially when hips become “tight” with long travel sessions in-season.

Once strength has been established in the posterior chain then we work towards making those moves more “powerful”, partial Olympic lifts, swings, explosive DL’s or fast RDl’s, not to mention depth jumps etc…

Here’s some videos to give you ideas of moves to use to STRENGTHEN the posterior chain and glutes.

Obviously we don’t just want to work or develop the posterior chain and forget about the other muscles in the lower or total body. But the reality is that the “front-side” of the body because we can see it in the mirror gets far more attention than the rear. Thus leading to the problems described above. Hopefully you are engaged in a balanced strength and conditioning program that will allow the body to work as it should synergistic-ally!

4.Integrate

The last piece of the puzzle for many is transferring over all the gym and mobility work to the bike. Well the easiest way to deal with integrating your hip hinging and posterior chain strength on the bike is to be mindful! Much of the benefits will transfer on their own via better posture and mechanics, but a little bit of mindfulness goes along way.

Aim to ride technically challenging or rough sections relaxed and tall, pop off anything you can see and be passively reactive! Now Passively re-active sounds like an oxymoron but what it means is you want to stay relaxed on the bike let gravity flow you over the terrain but at all times be looking for the split second spot on the trail where you want to actively push the bike down, extend your legs or pop off a lip. Use your new found hip strength and control to make speed, deal with gravity and cover ground faster and more comfortably!

By all means actively working the hip extensors on the bike with bunny-hops and explosive cornering is a great option also!

Finally here are some videos for all you visual learners:

Check out Point1 Trained, FMD superstar Neil Stewart from the 59 sec mark here to see how explosive he is through a very short range of hip motion but likewise how strong and stable his torso/hip angle stays when riding.

https://www.youtube.com/watch?v=QsOn75DCANA#t=59