Training your energy systems: The Sprint System (ATP-PCr, Phosphate)
This article is Part 1 of a 3 part series that outlines the three basic energy systems used in sport, their interactions with one another, and how to train each one.
Below the Introduction (technical explanation), we offer 6 sessions (in 3 stages) for training the Sprint System.
Introduction
Skeletal muscle is powered by one and only one molecule- adenosine triphosphate (ATP) (2). The body stores only a small amount of this ‘energy currency’ within the cells which is enough to power just a few seconds of all out exercise – this means the body must ‘create’ ATP on an ongoing basis. (5) Understanding how it does this is the key to understanding energy systems. It is important to remember the energy systems do not work in isolation to one another. Every movement by the body requires interaction between each of the energy systems and it is impossible to isolate one system from the others.
An ATP molecule consists of adenosine and three (tri) inorganic phosphate groups. When a molecule of ATP is combined with water (a process called hydrolysis), the last phosphate group splits away and releases energy. The molecule of adenosine triphosphate now becomes adenosine diphosphate or ADP (2).
To replenish the limited stores of ATP, chemical reactions add a phosphate group back to ADP to create ATP. This process is called phosphorylation. If this occurs in the presence of oxygen it is labelled aerobic metabolism or oxidative phosphorylation. If it occurs without oxygen it is labelled anaerobic metabolism (2) or glycolytic metabolism.
Note – Each of the 3 energy systems have contrasting powers and capacities. The power of an energy system refers to the maximal rate at which the system can produce ATP, while the capacity of an energy system refers to the potential that system has for ATP resynthesis.
ATP-PCr
ATP and creatine phosphate (also called phosphocreatine or PCr for short) make up the ATP-PCr system. PCr is broken down releasing a phosphate and energy, which is then used to rebuild ATP. Recall, that ATP is rebuilt by adding a phosphate to ADP in a process called phosphorylation. The enzyme that controls the breakdown of PCr is called creatine kinase (5).
The ATP-PCr energy system can operate with or without oxygen but because it doesn’t rely on the presence of oxygen it said to be anaerobic. The resting levels of ATP and PCr in skeletal muscle are in the range of 25 and 70 to 80 mmol/kg dry mass respectively, and appear to be relatively unaffected by the state of training. (6) During the first 5 seconds of exercise regardless of intensity, the ATP-PCr is relied on almost exclusively. A total depletion of ATP does not occur even in extreme exercise conditions, although a 30 to 40% decrease in muscle ATP has been reported. In contrast, almost complete depletion of PCr stores is possible (6). Combined, the ATP-PCr system can sustain all-out exercise for 3-15 seconds and it is during this time that the potential rate for power output is at its greatest (1).
When activity continues beyond this immediate period, the body will rely on increasingly greater contributions from the other energy systems to supply the required ATP for muscular contraction. Training the Sprint System for sport, to improve power and capacity requires maximum effort work with long periods of recovery. 1:10+ work:rest is recommended with all out efforts of 1-15s. The relatively long recovery periods are required to allow full replenishment of the ATP-PCr stores prior to the next effort.
Training The Sprint System (ATP-PCr, Phosphate) Sessions
Level 1:
Maximum effort 20m sprints
2 blocks of 5 X 20m efforts starting from different body positions
Easy walk back recovery
2-3-minutes recovery between blocks
1:10+ work:rest
Maximum effort kneeling ball wrestle
2 blocks of 5 X 5s efforts starting each new effort on 60s
1:10+ work:rest
2-3-minutes recovery between blocks
Level 2:
Maximum effort sprints with controlled change in direction
Accelerate as hard as you can to marker at 10m
At the 10m marker choose to cut either left or right and maintain speed through to marker 5m away
Easy walk back recovery
2 blocks of 5 X 15m efforts- starting from different body positions
1:10+ work:rest
2-3-minutes recovery between blocks
Maximum effort standing ball wrestle
2 blocks of 5 X 5s efforts starting each new effort on 60s
Emphasis on education of wide base of support, using low body position to advantage etc.
1:10+ work:rest
2-3-minutes recovery between blocks
Level 3+ :
Open partner chase drills
Reacting to partner starts, rats/rabbits game, agility belts
1:10+ work:rest
Use of external resistance (sleds, stretch bands, parachutes) –
Ensure maximum effort and emphasise quality each effort
Working up to efforts of 15s
Ensuring that external resistance is managed so that movement patterns are not negatively impacted- e.g.: 7-10% of BW for sled load
Maintain 1:10+ work:rest
Chase, catch & wrestle drills
Working in restricted spaces (5m X 5m for example)
1 partner evading with the other partner attempting to catch, hold and then both wrestling for the ball against the clock
Working up to wrestle efforts of 15s
Maintain
1:10+ work:rest
References
1. Baechle TR and Earle RW. Essentials of Strength Training and Conditioning: 2nd Edition. Champaign, IL: Human Kinetics. 2000.
2. McArdle WD, Katch FI and Katch VL. Essentials of Exercise Physiology: 2nd Edition Philadelphia, PA: Lippincott Williams & Wilkins. 2000.
3. Noakes TD. Physiological models to understand exercise fatigue and the adaptations that predict or enhance athletic
performance. Scandinavian Journal of Medicine and
Science in Sports. 10, 123-145. 2000.
4. Stager JM and Tanner DA. Swimming: 2nd Edition; An International Olympic Committee Publication. Oxford UK: Blackwell Scinece Ltd. 2005.
5. Wilmore JH and Costill DL. Physiology of Sport and Exercise: 3rd Edition. Champaign, IL: Human Kinetics. 2005.
6. Gastin PB. Energy system interaction and relative contribution during maximal exercise. Sports Med Journal. (31) 10, 725-741. 2001.
7. Ross A and Leveritt M. Long-term metabolic and skeletal muscle adaptations to short-sprint training: Implications for sprint training and tapering. Sports Med Journal. (31) 15, 1063-1082. 2001.
This is Part 1 of a 3 Part Series. Click here for Part 1 and 2.
Part 2: Training your energy systems: The Glycolytic (Anaerobic) System
Part 3: Training your energy systems: The Oxidative (Aerobic) System
This article is an excerpt from the Australian Rugby (ARU) Player Development curriculum, authored by our Pro coaches David Boyle and John Mitchell.
Click here to see David Boyle’s Rugby Union Training Programs.
Click here to see John Mitchell’s Basketball Training Programs.
Cameron West
Cameron is the Director of Pro Training Programs