Tag Archives: sprints

Sprint on the Beach for HIIT Cardio!

Calling all athletes, what kind of surfaces are you sprinting on these days? We truly hope you are not sprinting on Running-Virginia-Beachconcrete surfaces, unless you are sprinting away from your girlfriend because you forgot it was her birthday. Otherwise sprinting on concrete is a big no no and could cause a potential injury and are tough on your joints overall.

We remember when we were kids and we used to have sprint competitions against our friends on concrete surfaces, boy those were fun until one of us took a hard spill. After thinking about that hard spill, we think other surfaces would be more optimal to sprint on. All kidding aside, one of the best surfaces to do some all out sprints or HIIT cardio is on sand. Yes, sand, as in beaches, beautiful weather, and hot babes all around. Now, we know everyone doesn’t have access to sand surfaces, but for those that do it’s time to try doing your sprints on them.

Sand surfaces are harder to walk and run on than other surfaces because the feet slip and sink, which requires the leg muscles to stabilize the feet during the application of force. We promise you will not be disappointed with how grueling and tough sprinting on sand surfaces are. Oh and your joints will thank you in the long run, along with the rest of your body.

Where’s the proof in all this mumbo jumbo sprinting in sand talk, you ask? Before we discuss the study, we would like to give researcher Chris Beardsley a round of applause for discovering this study. A 2012 study conducted in the Journal of Science and Medicine in Sport, tested the biomechanics and predicted energetics of sprinting on sand surfaces. Previous researchers have observed that the energy cost of walking on sand is 1.8 – 2.7 times that of walking on from ground, while the energy cost of running on sand is 1.2– 1.6 times that of running on from ground. If you think about it, that is a pretty significant difference and could really be beneficial in everyone’s favor, especially athletes training in pre-season or possibly for rehabilitation purposes.

So what did the researcher’s do?

running-surfaces-pros-and-consThe researchers wanted to compare short sprints with or without changes in direction on sand, grass, and artificial turf. So they recruited 29 male professional soccer players

(7 defenders, 15 mid- fielders and 7 forwards). After a standardized 12-minute warm up, the researchers asked the athletes to perform a 12m maximum speed sprint and a 24m maximum speed shuttle sprint (with a 180 degree change of direction). The athletes performed both of these sprints on sand, grass, and artificial turf. Not concrete surfaces as we mentioned earlier, could be disadvantageous.

So what happened?

Measurement decreases on sand: The researchers observed significant decreases in average speed, maximum speed, average acceleration, maximum acceleration, average stride length, flight time, mechanical power, and stiffness on sand than on grass or artificial turf.

Measurement increases on sand:  The researchers also noted that average energy cost, average metabolic power, and contact time were highest during sprinting on sand.

Changes in efficiency in sand: The researchers found that efficiency values (i.e., the ratio between mechanical power and metabolic power) of the sprints were 0.17 on natural grass and artificial turf, while the ratio was only 0.12 for sand.

Similarity in stride frequency across all surfaces: The researchers were surprised by the lack of variation in stride frequency between the various surfaces.

So what did the researchers conclude in all of this?

This can’t be a study if there’s no conclusion right? Well, the researchers concluded that running on sand could be a useful tool for the following: training, injury prevention, and recovery. Pretty darn good benefits if you ask us. The main reasons they came to this conclusion was due to the stiffness values and how maximal speeds become lower on sand surfaces. Not to mention as we said earlier, this could serve your body well over time from possible joint issues or even the famous “shin splints” which can be pretty painful. The researchers also noted that “it is possible to carry out maximal intensity sprints on sand without reaching maximum speed, with lower stiffness, while also maintaining the same stride frequency but by reducing stride length, which represent less injury risk.” At the end of the day we are pretty sure everyone wants to stay injury free in order to maximize their full potential.

Wrapping this up

So we have some pretty cool data here to support the notion that sand is indeed a great and beneficial surface to do sprints on. Now, we are not saying that sprinting on grass, turf, or tracks are bad. We sprint on those surfaces all the time and have no pain what so ever. We are simply saying that sprinting on sand has its valid benefits and are very tough due to how your feet slip and sink in the sand to create the leg muscles to stabilize the feet during the application of force. Oh yes, not to mention if you have access to a beach then why the hell not take advantage of some awesome weather and do some sprints while flexing your guns and glutes. Overall you can’t go wrong with sprinting on sand, it’s great on your body, great for rehabilitation, great scenery, and whether you’re an athlete or not, just get out there and do some damn sprints!


(1)Gaudino, Gaudino, Albertia, and Minetti, Biomechanics and predicted energetic of sprinting on sand, Journal of science and medicine in sport, 2012.

About The Authors:

Chris and Eric Martinez, CISSN, CPT, BA, also known as the “Dynamic Duo” operate a world class personal training and online training business “Dynamic Duo Training,” They’re also fitness and nutrition writers, fitness models, and coaches that love helping people reach their goals. Their philosophy is “No excuses, only solutions.”

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Conventional Sprints or Resisted Sprints?

By: Eric and Chris Martinez

            What does a body well? Walking, treadmills, jogging, or perhaps sprints! Just ask Usain Bolt and the answer will be crystal clear. What kind of sprints you may ask? Well, we will keep it simple and refer to two specific types, conventional sprints and resisted sprints, better known as “sled drags” in this case. Very similar toBolt of Jamaica starts in the men's 200 metres heats during the world athletics championships at the Olympic stadium in Berlin Santa Clause dragging his sled around full of presents during Christmas time. All kidding aside, if you do not know what a “sled drag” is, in a nutshell it’s a device used for training purposes where you put resistance (weights) on it and pull it.  And yes, these two types of sprint methods can be used as a HIIT protocol, we already anticipated that question. But, in this article we will not be discussing these sprint variations for HIIT purposes. Instead we will be discussing the effects of conventional sprints and resisted sprints training to see which one is better for acceleration, athletic performance, and just overall better gains.

You may be thinking well why sprints and not a different type of training method to determine this? Well, since team sport athletes rarely have time to reach top speeds during play, the ability to accelerate quickly during a sprint is more important than maximal velocity. Researchers have found that assisted sprint training can help to develop stride frequency, while resisted sprint training may help increase recruitment of fast-twitch fibers, aka build more muscle. In a study done by the Journal of Strength and Conditioning Research, West et al. determined the effects of resisted sprint training on acceleration in professional rugby players. Better yet, they wanted to compare the effects of a program comprised of both weighted sled towing and speed training with a program comprising just speed training.

So what did the researchers do you ask? They recruited 20 male rugby players and designed the combined sled and speed training programs. The (SLED) group did 3 x 20 m sled drags with 12.6% body mass in addition to 2 series of 3 x 20 m sprints with 2 minutes rest in between. The (SPEED) group did 3 x 20 m sprints and another 2 series of 3 x 20 m sprints with 2 minutes rest in between. In addition, the researchers tested the subjects over 10m and 30m sprints before and after the intervention. In addition to the sprint training, all of the subjects also took part in 3 resistance-training sessions, 3 conditioning sessions, and 3 skills sessions. So what happened was the researchers found that the (SLED) protocol improved both 10m and 30m sprint times by significantly more than the (SPEED) protocol.

  • 10m sprint times:

Over the 6-week intervention period (with 2 workouts per week), the (SPEED) protocol improved 10m-sprint time by 1.16%. However, the (SLED) protocol improved by

Approximately twice as much or 2.35%. This is quite a significant difference when comparing the two protocols.

  • 30m sprint times:

Similarly, the (SPEED) protocol improved 30m-sprint time by 0.96%. However, the (SLED) protocol improved by nearly three times as much, or 2.65%. Incredible how much different the protocols were in this one.

What did the researchers conclude from this study? They concluded that both (SLED) and (SPEED) programs can improve acceleration over 10m and 30m sprints. They also concluded that the (SLED) program, involving a combination of sled drags with sprint training led to greater overall gains. With that said, hopefully we can all agree depending on what our goals are that sled drags are the better option overall for athletic performance. Not to mention, are probably better for overall hypertrophy (muscle building) purposes. If you are just more of a conventional sprint type of person. In a study done by Wilson et al. Sprints caused more muscle retention because when you’re doing LISS (say fast paced walking) you’re not activating muscles the same way as if you were lifting weights. So when you sprint you have hip flexion, knee extension, and these are all similar to weightlifting movements. Also, sprints are another way to overload the muscle. Just compare a sprinters body composition to a marathon runners… more muscle mass!

Wrapping this up

            If you are new to sled drags or resisted sprints, you are probably wondering where in the world do I get a sled? Well, you can’t depend on Santa delivering it, but there are many different online sites to purchase them, or you can get creative and make your own. We have seen some very crafty inventions for resisted sprints. The take home message for this article is to get out of your comfort zone and try a new method of sprints, especially if you are looking to take your body composition to the next level. You have all the data you need above to prove why they are such a beneficial and effective training tool. We must warn you though, if it’s your first time doing a sled drag or resisted sprints, you will feel the punishment the next morning. But, just like any other form of training, it takes physical and neural adaptation, so don’t give up quite so fast just because you are in pain and your CNS feels shot out. You can always use the analogy we used earlier, would you rather have a marathon runner’s body composition or a sprinter’s body composition? We rest our case!

BTW, check out our cool vid:


(1)   West, Cunningham, Bracken, Bevan, Crewther, Cook and Kilduff, Effects of resisted sprint training on acceleration in professional rugby union players, Journal of Strength and Conditioning Research.

(2)   Wilson, et al. Concurrent Training: A Meta Analysis Examining Interference of Aerobic and Resistance Exercise. University of Tampa, FL. J Strength Conditioning. 


Eric & Chris Martinez

Founders, Dynamic Duo Training


Eric and Chris Martinez are identical twin brothers that are nationally known as the Dynamic Duo, nutrition and training coaches, fitness and nutrition writers, fitness models, and founders of Dynamic Duo Training- an up and coming world class website that provides customized training protocols, customized nutrition plans, motivational coaching, educational programs, and a carved path to live a dynamic lifestyle.  Both are CISSN (certified sports nutritionists via the ISSN).