The Aerobic Energy System and MAS for Rugby

Rugby is often referred to as an Aerobic-Alactic Sport. Meaning that the Aerobic energy system is the dominant energy system with bursts of short, high intensity work throughout the game. However, saying Rugby is an Aerobic-Alactic Sport is a very general overview as rugby is a sport that relies heavily on all three energy systems (ATP-PC, Glycolytic and Oxidative). The reality is you are never working just one energy system. You may have one that is more prominent, but there will be an element of all three in use at one time. Rugby is random in the way passages of play can last; anywhere from 20 seconds to 3 minutes plus, over an 80 minute period. This makes it a very complex sport to prepare for!

During my ten years as a professional rugby player I saw and experienced a wide range of conditioning methods to prepare us for On-Field Performance. In the early days there was a big emphasis on developing our Aerobic Fitness levels using 1,500m Forest Run Repeats, that make my stomach churn just thinking about. Over the years then the distances decreased with more emphasis on our repeatability of High Intensity Efforts over a range of distances from 300m, down to as short as 40m. This also included running on tracks, up hills, sand dunes…..a full range!

In this article, we are discussing the importance of developing the aerobic energy system, which I believe often gets overlooked by coaches…

So why is the Aerobic Energy System
so important for rugby players?…

The aerobic system will provide a significant amount of the energy for actions on the pitch and will replenish the phosphocreatine stores during all low-intensity activities. In addition, it has been shown that players with a good level of aerobic conditioning are able to perform more high-intensity efforts during a match than those with lower levels because of the aerobic system’s influence on recovery!

The best way for rugby players to develop the Aerobic energy system in relation to rugby is to develop ‘Aerobic Power’ which is a training method that will result in improving the anaerobic threshold.

Our Anaerobic threshold is basically the maximal speed (or effort) that the player can maintain and still have no increase in lactate. At this speed or effort, lactate levels in the blood remain constant. Any increase in effort or speed above this level will cause lactate and its associated high acid levels to increase and if continued will mean the player slows right down and will be ineffective. This is the main fatiguing factor for rugby players. In short, the higher the anaerobic threshold of a player the greater the work capacity of that individual will be!

One of the most effective methods of developing Aerobic Power and improving the anaerobic threshold is via improving M.A.S (Maximal Aerobic Speed) popularised by Dan Baker, one of the worlds leading Strength and Conditioning Coaches, who worked within Rugby for a significant amount of time, working with the Brisbane Broncos and Queensland Reds.

Dan Baker Described MAS as the following –

‘MAS relates to aerobic performance (VO2max) and forms part of the process for developing aerobic capacity and is expressed in meters/second (m/sec). In order to improve VO2max the training session should accStrength-and-Conditioning-Coach-Dan-Bakerumulate as much time at or as close to VO2max as possible. This is often problematic with continuous type running, cycling, rowing and swimming as it is difficult to maintain intensity sufficient enough to stress the cardiovascular system for long periods.

Interval type training for the aerobic system can potentially overcome this problem as it allows sufficient stress at the VO2max level while allowing adequate recovery for repeated efforts therefore resulting in more time at VO2max.

The most recent research shows that the amount of time spent at or above the 100% Maximal Aerobic Speed (MAS) appears to be the critical factor for improving aerobic power. It has been determined that performing a number of short intervals at above 100% MAS was a more effective method of building aerobic power than LSD training. This approach was also more effective than attempting to train only one interval continuously at 100% MAS.

 Specially, an intensity of 120% MAS was determined to be the best single speed for short intervals that are followed by a short respite (passive rest) interval, based upon the fact that this intensity allowed the greatest supra maximal training impulse (intensity x volume), in the comparison to 90, 100 and 140% MAS. Especially, intervals of 120% MAS for 15-30 sec followed by an equal respite interval of passive rest’.

Establishing your MAS

Simplest way to determine your MAS is get on a 400 m Track and measure the maximum distance you can run in 5 minutes (300 seconds). From there then divide the distance run by the time to complete the distance, this will then equate to your Maximal Aerobic Speed.

 For example if a rugby player runs 1400m in 300 seconds his 100% MAS would be 4.7 m/s.

 1400 ÷ 300 = 4.7 m/s

 In order to work out your 120% MAS, you simply multiple your 100% MAS by 1.2.

 4.7 m/s x 1.2 = 5.64 m/s

Dan Baker utilised the Maximal Aerobic Grids method consisting of rectangular grids, with the long side at 100% MAS and the short side at 70% MAS. You must complete each side in 15 seconds, with the full rectangle taking 1- minute to complete.

Rugby Players are expected to hit a corner at every 15 seconds. Obviously the long side is where the hard work takes place but also the shorter side (70%), is the active recovery and is a slow jog rather than a walk.

Every 2-3 weeks it may be necessary to increase the MAS % of the long side of the grid (not the short side, that remains at 70%) with increases of 5-10% recommended only if all corners of the Grids are completed every 15 seconds.

MAS Grid

Rugby Renegade ‘Maximal Aerobic Grids’ suggested sessions…
Try and complete 1-2 sessions a week

Week 1/2 – 3 x 5 minute continual Blocks at 100% MAS
(rest 2 mins between blocks).

Week 3/4 – 3 x 5 minute continual Blocks at 105% MAS
(rest 2 mins between blocks).

Week 5/6 – 3 x 5 minute continual Blocks at 110% MAS
(rest 2 mins between blocks).

Week 7/8 – 3 x 5 minute continual Blocks at 115% MAS
(rest 2 mins between blocks).

Week 9/10 – 3 x 5 minute continual Blocks at 120% MAS
(rest 2 mins between blocks).

 Then retest your 5-minute max. Distance run

 Increase your Work Capacity and you will
improve your On Field Performance!!

Article written by


Robin Sowden-Taylor
Senior S&C Coach
Cardiff Blues / ION S&C

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