Tag: Training

Dieting, Fasting

Why intermittent fasting isn’t for you

dsc_0574Having done intermittent fasting or IF as it is often shorted for probably close to 5 years I find myself quite capable of listing pros and cons and giving advice on whether it is a good idea or not. You could perhaps think that having followed it for 5 years I would recommend it to everyone as I must find it great and useful otherwise I would just have abandoned it, right!?

Well yes and no. I’m not bound by religion to fasting and I haven’t signed my life away to an employer legally keeping me from spending time on eating breakfast – so yes – I can abandon it anytime I see fit – which we will get to. But that does not thereby mean that I think everyone should adopt intermittent fasting. It is absolutely not for everyone. There are very good reasons for following a IF schedule, but there are as good reasons for not.

The primary reason for why you should keep away from IF is because you probably expect it to be some magic pill that suddenly will make you young, slim, muscular and energized.

Yes that is just some of the highlights from the almost mile long list of benefits of IF I have encountered from various sites. Of course if you are looking to make money of products relating to IF and you don’t care that much about your integrity, then you should by no means present a balanced view on IF shedding light on both sides of the arguments. But as I don’t stand to gain anything from your choosing of lifestyle I have no need to present anything else than what I have experienced and believe in myself.

Some of the things advertised as effects of IF are true. BUT if you are looking at doing if because of those, then for 9 out of 10 you are looking for a quick fix for a problem you don’t really want to face and you will not find it with IF either. A lot of the things ascribed to IF comes from “regular” fasting as research in this area has been more thorough than IF. Regular fasting where you fast for several days has been used quite a lot to help heal different types of ailments. But exactly how many of those benefits you can have by say fasting 16 hours out of each day isn’t really that well documented.

Perhaps it is a good idea to somewhat loosely define what constitutes intermittent fasting. The fasting part is quite easily defined – no calories. You can drink water, coffee or tea with nothing in it, that adds calories. There are some strong proponents of what they call “bulletproof” coffee fasting where you put like 5-700 kcal worth of butter in your coffee and still call it fasting because you aren’t eating anything. Well it might be good for your and fit your goals and schedule perfectly, but fasting – it is not. Intermittent implies cycling on and off. You could imply that over a long enough timeframe all fasting is intermittent, it is not like anyone keeps fasting and not gets back to eating – or if they do they won’t be redoing that experiment..

But exactly how you implement this “intermittent” part is up for debate. You could again argue that we already have some sort of intermittent fasting as we don’t eat from dinner till breakfast, which as the name implies breaks the nightly fast. But implementing anything that could be considered daily IF probably start at around a 16 hour fast window give or take. That’s the schedule I have been doing for the past 5 years. There are other implementations where you fast for 1 whole day each week or 2 days a week etc. Again there are many ways to do this, do your research and determine for yourself what you might want – or just ask, I’ll be happy to answer any questions.

The second reason why fasting isn’t for you is if you are considered a “hard-gainer” and are looking to put on weight. If you have problems eating enough by having 16 hours a day to eat, then it sure as hell won’t help to only have 8 hours to do the same. That is not to say that you cannot put on weight while doing IF – I have done it several times, but I am by no means considered a hard-gainer – I have the appetite of a full pack of grown up lions putting their teeth in a zebra after 6 weeks of licking salt from rocks in the baking sun.

I have seen way to many skinny guys wanting to do IF because they have seen guys doing IF that are very muscular and lean and want to look as them. The problem here is linking correlation with causation without taking all factors into play. Yes, they may look that way because of doing IF, but most likely they will have had a different starting point than a skinny kid. Most likely they will already have build quite a bit of muscle mass doing just regular bulking paradigms. Again not to say it is impossible for them or anyone to put on weight with IF, but have a honest look on yourself in the mirror and tell whether you have a hard time putting on weight or not. If you do, then IF probably isn’t the answer.

The final point I will bring in this post is probably one I will cover more in detail later on as I am not really totally settled on the answer myself to be honest, but still deserves a mention is what I will term environment. Not the one you try to save from global warming as I’m pretty sure IF has no play in that, but environment as in work, school, family etc. The environment you live in everyday.

The consequences/concerns here are somewhat split into two parts. One is explanation. Even though if you do 16/8 fasting you could probably time it to be when everyone else eats lunch and just not mention you don’t eat breakfast, unless of course you want to talk about it. But you will most likely end up in situations where you will have to explain why you aren’t eating breakfast and situations where you perhaps should consider breaking your fast and just eat. I have mentioned this before both in terms of competitions and in “family-situations” where for instance your grand mother has spend a lot of time on preparing a nice breakfast for you, then just break your fast and eat. Don’t be a over-religious prick.

The other concern is also to do with family. If you live with a girlfriend/boyfriend then he or she should be understanding even though you still can take some days off to serve breakfast in bed etc. but it gets more complicated if you have kids. Because on the one hand you could just keep up your lifestyle and don’t eat breakfast but my concern would be how would this impact the kids general view on food and eating. It could be possible but it could might as well be negative.

As said earlier I don’t have all the answers to this and won’t go into further detail, but just to say that there are some things you should consider before deciding upon IF as the answer to your dieting questions. But all in all it is a great protocol for the right types of people, otherwise I wouldn’t have kept it for all these years. It keeps me lean, sane and performing as I want so no complains here. But once I find myself in a family setting with kids I might take it up for consideration.

Training

Wave loading – a different rep-scheme for strength

If you’re a beginner just starting or started with strength training, then rep-schemes should be the least of your concerns. Stick to 5×5. Universally across most domains this just works best. Get good at the specific movements and get strong! Your progress will be way faster and way more unpredictable than any rep-scheme could predict. So just stick to 5×5 and keep adding weight. If you are an intermediate or advanced lifter this rep-scheme might be of interest to you. I’ll present the actual rep-scheme and some pointers as to where I see it as being most valuable and where it might not be the best solution.

Once you’re a few years into lifting you’ll probably get to a point when you are having a hard time getting any stronger in specific movements – your progress has somewhat stalled or plateaued. This is where training becomes interesting – this is somewhat the BMW-syndrome of the strength world – a lot of people get to this stage, but few people progress from here.

This is where some of the very complex training methodologies start to get into play. But advising you to use one of those would kind of speak against the title and aim of this blog. I am not hereby saying that you should stay clear of them, because they might be the best way to reach your goals – I just like to get as far as I can with simple approaches.

In the past I have had quite good progress with Wendler’s 5/3/1 – but ended up stagnating for overhead press and feeling burned out in deadlift – where the latter may very well be the explanation of the former. I tried modifying it and not going to failure in the last set as is prescribed, but this did not seem to solve all my problems. I then started looking for alternatives and went back into my nice big collection of rep-schemes and found wave-loading.

The basic principles are very simple; you advance in waves – hence the name and try to complete anywhere from 2 to 4 waves in a specific lift per training session. You start of with a 1RM weight or what I would recommend to be a 90-95% of 1RM. Then you go back 5kg or 10lbs depending on equipment(keep it simple). In this specific case it is kg and from my strict overhead press. 95kg is somewhere between 90-95% of my 1RM. Then following this scheme I would start my first wave with 3 reps of 75kg then 2 reps of 80kg and 1 rep of 85kg. Then I would start the next wave and go on.

Waves 90-95% of 1RM 95
3 rep 2 rep 1 rep
1. wave 75 80 85
2. wave 80 85 90
3. wave 85 90 95
4. wave 90 95 100

It should be rather easy for you to do make your own formula but here is a link to a spreadsheet with the formulas working – where if I have done it right you should be able to edit the 1RM figure. Google spreadsheet wave loading

The philosophy is that on any given day you should be able to complete 2 waves. Completing 3 is a good workout and completing 4 is an awesome workout! If you can complete 5 waves then you started with too little weight. Then when do you decide to stop – do you go to absolute failure? I would not recommend it. I would go with your “feel”. You usually have a pretty good idea whether or not you will be able to get the number of reps with the given weight – stop if you do not think you can complete it. This is designed to build strength so don’t overuse the failure part.

But the important part here is that you should be able to complete 2 waves on any given day. Completing 2 is acceptable! Don’t be mad at yourself for not completing 4 on each workout. You can’t be exceptionel in every workout.

I find this rep-scheme worth a try if you are a intermediate or advanced lifter that has plateaued on for instance strict overhead press or benchpress. Or intermediate lifter stagnated on squat or deadlift. I would not recommend it for advanced lifters in squat or deadlift as I see too big a risk of burning out. But have a go yourself and see – it is very simple to implement and try.

Simple advice, Training

Does foam rolling work? Mobility, warm-up and science.

There has been a lot of different opinions when it comes to foam rolling. Some people swear by it while others says it is a total waste of time and highlights the foam-roller as the most over-hyped accessory in the fitness industry. But now finally there has been some scientific research that looked into the matter and shed some light on it. It will probably not put the arguments to rest and I would be surprised if it’s the last research paper on this subject, but nevertheless it is a good place to start. For good measure the link to the study is in the bottom of this post.

I can’t even remember where I heard about foam rolling for the first time, something inside me says it was probably Kelly Starrett – but whether that is just because he has been at the forefront of the proponents or it was actually the case I can’t remember.

My opinion about it however has stayed somewhat neutral. I am in no way against it but does in no way see it as the holy grail of neither warm-up nor mobility practice. My main use of it has always been to release some tension in the upper back. For this it is absolutely brilliant! But rolling around smashing my quads or hamstrings before squatting for instance never really caught on with me. I have always been a proponent of warming up with the movements you are about to do in your training.

But now the big question is whether I should abandon my usual practice and go all-in on the foam roller or stick with what I have been doing so far?

This first research paper focused on stretching and flexibility of the hamstring by comparing PNF stretching with foam rolling and a control group. For good measure PNF stretching is where you contract and release into the stretch and is generally seen as superior to static stretching and therefore a good and high measure on which to compare foam rolling.

The unsurprising find of the study was that PNF works compared to the control group – we know that. But the surprising find is that the foam-rolling group gained as much flexibility as the PNF group. In other words the foam rolling actually gave as much flexibility as what is otherwise seen as the superior way of gaining flexibility. I had by no mean expected that! I could perhaps have understood if it stood the ground against some weaker static stretching but this finding is quite surprising.

So this leaves me with my original question to answer: will I abandon my usual practice and go on a foam-rolling frenzy. Probably not. For one this study only looked at flexibility and not warm-up. I still believe the best way to warm-up is to do the actual movements you are about to perform to both get blood into the muscles but also get the CNS firing the rigth places. But I must admit that this study perhaps will have me spend some more time foam-rolling, not the least in times where I feel tight in some areas.

There you have it – science now backs foam-rolling. That must be the news of the week from the fitness world, something that is hyped and actually seems to work. It is even affordable if you get the basic version from amazon: BLACK High Density Foam Roller or if you want the Rolls Royce: Trigger Point Performance Foam Roller, Orange

And finally of course the link to the actual study: The foam roll as a tool to improve hamstring flexibility

Sprinting

Sprinting – The art of the start – The first few steps

This will by no means be a full description of block starts, that will be beyond the scope of this post, but I will instead focus on the first few steps you take out of the blocks as they are some of the most important steps and sets you up for the rest of the race. If you get ‘em right the rest will come a lot easier. But easy is not a word to describe the path to mastering this. It can be hard to explain and even harder to implement as some of it seems counterintuitive and even feels slower when you do it compared to “normal” starts.

First of let’s look at a guy that masters this; Mr. Justin Gatlin. He’s in the middle in light blue.

Right – did you notice what he perfects that gives him the edge over the others?

The “usual/normal/old” advice about starts is to take short and quick steps – I had that reinforced by my first coach – not to take anything away from her, that’s what she’s been taught and now teaches on. But the thought behind this is that you build speed by a lot of small quick steps and then go on through the acceleration phase switching to longer steps. On the face of it this makes good sense – it even feels fast when you do it as you get to stomp away with violent high frequency. And this CAN be very effective – Kim Collins one of the best 60m runners still to an extent does this.

But one of the caveats of this method is that stomping away with short frequent steps you get more and more tight trying to apply even more steps at a higher frequency, lifting your knees and heels (as is taught and correct later in the race) to stomp harder, this leads to tensioning the entire body which then drains you of energy and the perhaps very good start you had – gets lost after 30-40 meters.

So then what should you do instead? Glad you asked!

What you want to do, and what I will show you Gatlin does, is take very long steps that almost drags the feet along the ground for the first few steps. You do NOT take short steps and you do not try to stomp hard on the ground as you should later in the race. You pull your feet forward using the shortest possible path and then apply force while “dragging” the other leg. Go back up to the video and watch Gatlin once again, focussing on his feet. They almost do not leave the ground for the first few steps, they are very close to being dragged along the ground instead of pulling his heel towards his butt.

So coming out of the block your first step is going to be long pulling with your knee from the back foot and totally extending your front leg, then as you put the first foot on the ground you now pull your other leg perpendicular to the ground in the same way – they are not going up and down but perpendicular to the ground.

If we now look at some stills from the video – starting with Gatlin’s first step:

See even though he did not pull his foot upwards he still gets as long steps as the others – on this picture it is hard to see any difference between any of them, but now look at picture number two:

Gatlin has “dragged” his foot along the ground giving him the shortest path to the next step. He is about to translate force through this leg while the others haven’t even come to put down that leg yet. Dragging the foot has given him an advantage already visible by the second step. From then on he just executes perfectly.

Apart from being very effective out of the block this also has the effect of setting you up for naturally progressing with longer steps. It is almost impossible and very counterintuitive to go from taking long steps to take short ones. Therefore doing this from the start sets you up for a much better remainder of the race.

But as I said earlier this start will look and seem slower when performed by itself. You will almost be “waiting” for your first step and the frequency of your steps will be a little slower – therefore it seems counterintuitive and most people will turn back to their “normal” high frequency starts once in competition as this “feels” quicker. But if you are really strong and keeps practicing especially competing with training partners to force the head into using this technique, then your starts and the rest of your race will come more naturally.

As I have written about earlier (Competition preparation do’s and dont’s) you of course should not change your technique on competition day. Leave it for practice and get comfortable with it before ever attempting it in competition. Competition should only be “replaying” what you have practiced.

Competition, Training

Competition preparation do’s and dont’s

Preparing for a competition in most sports should be so simple, yet so many people get it wrong – even experienced athletes.

This great quote says it all:

You can’t win a competition in the last week of preparation – but you CAN lose it!

People suddenly get worried that they haven’t done everything right, especially within the last week and the “do more” paradox seems to kick in. This is especially common in this day and age with all the available information at your fingertips.

If you do it right, competition should be no different than your training – except for a bit more pressure of course. But if you prepare in the right way, then the pressure should be the only “new” thing you would have to deal with.

Let’s start with what you should not do and why. I will present my examples in the domain of sprinting – but it could be substituted with just about any sport, even team sports.

Don’t overcompensate in the last few weeks before competition

This can’t be stressed enough. Overcompensation during the last few weeks has led to so many injuries across all domains. Suddenly with a few weeks to go you come to doubt whether you have had done enough of say 300m sprints to prepare yourself for the 200m. This could be because someone suddenly questions why you haven’t had more or you read somewhere that you can’t compete without have x number of 300m sprints. Then you panic and the last week before competition you 10x the volume, run a lot of 300m sprints and either burn out, overtrain or gets injured. This is NOT the way to do it. If the advice is really good – then write it down save it and incorporate it in your long term planning for the next competition – NOT the last week before.

Don’t eat or drink anything special the day before or on competition day

With the rise of supplements, energy drinks and what not this really matters as well. Do not suddenly try a new supplement or energy drink on competition day, you have no idea how your body or stomach reacts. It might be the best energy drink or pre-workout supplement in the world but if it upsets your stomach you will be running for the toilet and not the finish line – that will only win you a fun story – not a medal.

A few weeks before actual competition, try to replicate competition day as much as possible. You shouldn’t necessarily go all out on effort, but replicate your meal- and supplement intake, at the exact time of day. If you for instance always train in the evening, but competition is in the morning, then try to replicate this and see how your body reacts. If you are into intermittent fasting like me, then you might want to break your fast early and have some carbohydrates. But common for all – try it a few weeks before and not on the actual day of competition. Even the meal in the evening before can have an impact. If you have lived of the same 4 meals for months and then suddenly tries something completely different the day before, like very spicy food, then you might be back to the race for the toilet as opposed to the finish line. Just don’t do that.

Don’t change your equipment or strategy on competition day

Don’t suddenly start your sprint with the left leg in front as opposed to your regular right leg because you have seen a Youtube video explaining this as being best – and yes I have actually experienced people who did that. Competition day should as far as absolutely possible reflect your training. Changing something on the day of competition is way more likely to ruin your competition than improve it in any way.

Don’t let other peoples preparation throw you off on competition day

Do not suddenly start your warm-up 1½ hour before competition because some of your competitors does so, if you have always used 45 min to warm-up. Or implement some of their stretching, preparation/warm-up routine. Stick to your plan! I actually caught myself almost slipping in this one a few months back. I always start my warm-up 45 min before a race. I like to keep it short and to the point – too much warm-up either bores me or wears me out. But at a 50 meter indoor sprint competition all my competitors started their warm-up a little more than an hour before the race. Until I caught my own thoughts, this actually made me a little uncomfortable. Had I missed something? Should I be warming up now? Is my warm-up too short? And of course the answer to all those questions is a big capital NO. My competitors preparation had gone inside my head and messed with it. I should do exactly like always and stick to my warm-up routine. It had worked for me in training so of course it would work for me in competition – and so it did – I won the event.

If you have done your training and preparation right then competition is simple. Not easy – but simple. You should not be doing anything you haven’t done before. You should be able to give your full attention to dealing with the stress of competition, the zippers and knots on your training clothes that suddenly jam, the 10 times you have to go to the toilet and try to pee etc. But you will have the mental capacity to deal with this because you know you have done everything else a 100 times in training so no need to worry about that or take any decisions.

Good luck with you next or first competition. Competing is and should be fun – being well prepared helps achieve this.

Simple advice, Sprinting

“Nailing” perfect sprint technique; high knee, quick recovery and toes up with one simple tip

I absolutely do not consider myself an expert on sprinting as it, at least by track & field terms, is not something I have done my entire life. But what I do consider myself quite an expert on is biomechanics and applying well researched concepts to actual sports specific training. And with the title of the blog containing “Keep It Simple Stupid” I am quite a sucker for simple tips and tricks, which is exactly what this is.

I have never been a particularly bad sprinter, meaning that I was always able to run rather fast and accelerate very quickly. Having always been fascinated by sprinters this ability has somewhat stuck with me through all my different sports and training methodologies. But starting track and field sprinting really opened my eyes to how much specific technique and applied methodologies that are to a great 100m race.

I can pinpoint numerous things I am working on to reduce my 100m times, but one of the things that I really found hard to comprehend was the notion of the high knee lift. How could lifting my knee higher in any way improve my speed? For all I could see it would take longer for me to lift the knee meaning a reduction in frequency – the knee lift in itself did not from my view yield any result. The high knee lift had to come from something else. Adding to my skepticism I think that I had read somewhere that the high knee lift came as a result of the force production on the ground – meaning more force production = higher knee lift and not that the knee lift in itself “did anything”. This sort of made sense to me until I read a piece that totally shattered that view.

Another common advice getting thrown around is to recover your leg quickly and keep your heel close to your butt when recovering your leg. What this advice ends up doing is mimicking “butt-kicks” which is actually not what we are looking for. We are not trying to recover the heel all the way up to the back of the butt, but we are trying to make the lever as short as possible to quickly recover the leg and have it ready for the next step. A better analogy is keeping the heel close to the hamstring which is actually closer to what we are trying to obtain.

Finally there is the “toes pointing up” that comes together with the high knee lift – this puts tension on the calves and enables for a more explosive force-development through the ankle by way of the “stretch reflex”. These three things along with numerous other techniques is what the new athlete has to think about while sprinting max effort – and oh – remember to relax while you’re doing it…

There is actually great debate as to exactly what makes for the perfect sprinting technique. All scientific papers seems to have a very hard time really pinpointing what the “right” technique is, but one thing that seems to stand out across all scientific papers is the fact that all great sprinters have very short ground contact in common. Thereby saying that they are able to produce tremendous amount of force in a very short timeframe and then quickly recover the leg.

What I was not able to comprehend was as said earlier how lifting my knees higher could help achieve any of this. But luckily someone explained it to me in a way that made biomechanical sense to me.

Getting your knees higher achieves a longer travel for your foot to enable it to punch the ground harder. This is the same analogy as if you were to punch a sandbag really hard, you would not start with your hand 1 inch away from it – you would pull it back and then punch. The same goes for high knee lift – what you are doing is pulling your knee higher in order to explosively and violently punch the ground harder.

When this was explained to me, it suddenly made sense. The reason for teaching high knee lift is that it has been found to be the way you can punch the ground hardest and produce the most amount of force. Now my brain was on track with why – then the next step was how?

Luckily there is a little tip that at least for me made everything just click. High knees, quick recovery close to the hamstring and toes pointing up. The very simple tip is to imagine that there is a long nail sticking out of your opposite knee that you need to step over each time you recover your leg. If you do this, even just walking slowly you will realize that in order to do so your toes will automatically point upwards to get over “the nail” and you automatically pull your heel close to your hamstring and not back up towards your butt and finally in order to get “all the way over” this imaginary nail you need to pull your knee high – in short everything that is taught as good sprinting technique. Try it out for yourself – for me i just sort of made everything click – so hopefully it can do the same for you.

Training

Best bodyweight exercises for abs

L-sit gymnastic rings
Doing L-sit on the beach at Ngapali. Myanmar(Burma)

Oh the famous abs… So many hopeful aspirees, so many teachers and so few victorious in their quest.

What I’ll share of course is the easy, no work all magic pill that transforms your sexy curvy stomach into a flat, tight 6-pack. You’ll only have to work once a year for 3 seconds, so that your awesome well trained attention, do not miss any cat-videos or talent shows.

Kidding aside – this post won’t give you overnight 6-pack or maybe even ever get you near, that’s all on your court. What I’ll describe for you is my philosophy of ab-training. Boiled down to a couple of hard and somewhat advanced exercises that has been my favorites for the past several years.

DSC_0842_2As you of course should not take advice on how to quit smoking by a chain-smoker, I’ve included a couple of pictures of myself, just to let you come to your own conclusions as to whether I walk the walk or not. Further more you can probably find one or two very recent pictures on my Instagram account.

Having had a 6 pack for the last probably 6 years I think I have developed some sense of what it takes to achieve it – and no unfortunately my 6 year old photos does not include me with long hair or a newspaper to validate the claim, but I can provide ‘em – your choice to trust me or not.

6-packs are as you probably know primarily made in the kitchen, but diet is a complex topic for another day. (Please let me know if you want to know anything specific.) But yes I said “primarily” – not “solely”. They are a function of size and body fat percentage, so you can basically manipulate anyone of them to a degree. Low bodyfat is the main factor, but the size of your abs will determine how low you need to go before they are visible.

So what NOT to do. Don’t train your abs everyday – yes there are stories of people who did this and can show results to match – but it’s just not the best approach. Train hard, then REST- Allow your muscles to rebuild and become stronger, otherwise you are only breaking down and not rebuilding.

Don’t do crazy 50-100 rep sets of sit ups or crunches. Train your abs as you would with your chest or arm – and if you are doing 50-100 rep sets for those… – just don’t. Use weight to keep your reps low or choose a more demanding ab exercise. I don’t believe I have ever done reps past 10 repetitions. But yeah 5-15 would be the target rep-range.

First exercise I will highlight is static. It’s the exercise that I do on the first picture of this post, commonly known as the L-sit. Doing it on rings of course is a lot more demanding and adds much more strain on arms and shoulders as stabilizers, so wait with those. If my target of the exercise was abs alone, I myself would not even use rings, as they would make my arm and shoulders tired way before my abs. L-sit on rings for me is more a transition when doing ring-routines – for core ab work I would do L-sits on the floor, parallettes or between chairs.

So that is where you will start. As a beginner I would start between chairs or similar platforms. Press the surface as hard as you can with your hands, which should force your shoulders down and then contract your abs as hard as possible. If you cannot keep you legs straight, then start with them bent and work from there. You should feel the strain primarily in your abs, it is possible to feel a burn in anything from your hips to legs, but then you are not doing it right, experiment until you feel the burn primarily in the abs. Let’s say you can hold the position for a maximum of 20 seconds, then do 5 sets of 10-15 second holds and try adding 5 seconds every couple of weeks. Your goal is to hold a perfect L-sit for 60 seconds!

The second exercise I will highlight is rather advanced – but delivers bang for the buck like nothing else once you have mastered it. It’s the famous dragon flag or body lever. It is quite hard to find videos of people doing them correctly, but this guy pretty much nails them:

What you should notice is that he keeps his body straight or slightly over arched at all times. Even just a slight kip in the hip will dramatically decrease the difficulty and thereby the effect. Think of leading with your hips and not with your toes and keep a straight or slightly over arched body. But be careful, this exercise is extremely demanding and can cause quite a bit of pain in your lower back if you are not strong enough. I would recommend doing slow negatives until you are strong enough to begin pulling yourself back up. If you have a good solid 20-30 second L-sit you should be able to start working on these as well. Again if you get very advanced, then add ankle-weights instead of hammering out 15-20 reps.

These two exercises are stables of my ab-training. Ab-rollouts, hanging leg raises in stall bars, v-ups etc. find their way as well, but I honestly believe that my ab strength and size are primarily down to those two exercises.

So to summarize. Train your abs 2-3 times a week, train them hard and heavy, just like chest or arms, use progression and finally and most importantly fix your diet!