Rugby Fitness components Metabolic conditioning Metabolic conditioning refers to the ability of the energy systems to produce the necessary energy for a player to perform throughout the game. It can be divided into the main factors of aerobic power, anaerobic power and lactate tolerance. Aerobic Power Aerobic power is the ability to produce energy through the aerobic slow energy system. As explained previously the aerobic slow system predominantly supplies energy for exercise lasting over 90 seconds in duration and is vital in the recovery process from repeated bouts high intensity exercise. A well-developed aerobic slow system results in less lactic acid being produced at a given exercise intensity due to the reduced demand on the anaerobic medium system. The aerobic slow system has great importance in removing lactic acid from the body. The greater the aerobic power the more efficiently it can clear lactic acid and therefore allow exercise to be performed at a higher level. Anaerobic Power The ability of the anaerobic systems to produce energy is referred to as an athlete’s anaerobic power. You will recall that anaerobic energy is produced in two ways. Through the anaerobic fast system, which is the major contributor for the first 0 - 10 seconds of exercise and secondly through the anaerobic medium system which supplies energy at the beginning of exercise, being the major provider for the first ninety seconds. The system is also used in longer durations where the demand for energy is too large for the aerobic system to handle alone. Intermittent bouts of high intensity exercise e.g. repeated sprints with rests in between also rely heavily on this system. An athlete who has strong anaerobic power is able to sustain higher intensity levels and perform more intense sprints without suffering from undue fatigue. Lactate tolerance. As discussed earlier lactic acid is the by-product of the chemical reactions within the anaerobic medium system. The build up of lactic acid interferes and impairs the muscles ability to contract. Lactate tolerance is the main fatiguing factor for most team sports. Through correct training of this attribute the body adapts to functioning in the acidic environment therefore resisting fatigue more efficiently during exercise.
Strength Strength can be defined as the maximum force produced at a specific velocity (speed). The definition refers to the element of how quickly a force is applied. The speed a force is applied is an important yet often overlooked element of strength. Traditionally strength is perceived as the ability to move the heaviest
weight possible. However, the force- velocity relationship states that this is just one aspect within the overall picture. It can be seen that it takes around 0.8 sec to produce maximum force e.g. lift the heaviest weight you can handle or push as hard as possible in a scrum. Many movements in sport are performed in around 0.2 seconds or less e.g. kicking, sprinting, passing, punching etc. In this time scale there is not sufficient duration for maximum force to be applied e.g. in sprinting the foot has left the floor after 0.2 sec, therefore any strength produced after this point cannot be used as the foot is in the air. The application of time to strength production means strength is classified as either slow speed maximum strength (~ 0.8sec) or fast speed strength.(~ 0.2 sec) Slow-speed strength. Slow speed strength is also referred to as maximum strength. It is the maximum amount of force that can be produced e.g. the most force you can push with during a ruck or maul. This is an important aspect in rugby where the player who holds the greater maximum strength will often prove dominant in contact situations. The ability to produce maximum strength is related to: Muscle size - The greater the size of the muscles the greater the amount of fibres there are to contract and hence the greater the potential for more force to be produced. Neuromuscular co-ordination - The brains abilities to recruit as much of the agonist muscles as possible while relaxing the antagonist muscles to allow the movement. This is the biggest influence on your strength. Fast-speed strength. Fast-speed strength, or just speed strength is defined as the force produced at high velocities. It is the force produced in around 0.2 sec or less. Training for speed strength increases the amount of force the athlete can produce within this 0.2sec timeframe. Neuromuscular co-ordination - The bodies ability to co-ordinate the agonist, antagonists and stabilisers to produce a fast, efficient and forceful movement. Core strength This can be defined as the strength of the muscles around the mid section that stabilise the hips and spine during movement. Strong core strength is essential to performance as it holds the body still which allows full force transfer. For example, when tackling a player you hit them with your shoulder. A strong core would allow all the force in your legs to be transmitted through into your shoulder and onto the opponent. A weak core would not transmit anywhere near the same force and you could see you body buckle and collapse under the pressure often resulting in a missed tackle. Speed Speed in its simplest terms is the time it takes to cover a distance. It is a product of stride length and stride frequency. The winner over a certain
distance is deemed the fastest e.g. the winner of Olympic 100m final is deemed the fastest man/women in the world. In rugby, as in other sports, speed is found to be more complex than first appears being made up of three different components: Acceleration - The time it takes to go from a standing or slow speed to maximum or higher speed. It takes between 20 - 50m to reach top speed, with elite Olympic sprinters attaining maximum speed at around 50m while novices needing just 20m. The ability to accelerate is heavily influenced by strength and neuro-muscular co-ordination. Maximum speed - The maximum velocity (speed) that can be achieved. The maximum top speed displayed by an athlete is dependent upon neuromuscular co-ordination and the legs fast speed strength. Speed endurance - The ability to maintain maximum speed or the ability to repeatedly perform successive sprints at the same speed. Speed endurance is dependent upon the metabolic conditioning of the anaerobic fast and medium systems Quickness - The ability to move a body part at the highest possible velocity. This is important in many sports such as boxing, racket sports or throwing events where the speed the arms are moved having a large impact on performance. In rugby quickness is important for passing and kicking the ball or in throwing a fake directional move e.g. side-step. It is closely related to neuromuscular co-ordination and speed strength. The three components of speed means you need different strengths dependent upon the distance being run. e.g. the winner of a 50m race will be the one with a greater acceleration while the 200m favours those with a greater ability for speed endurance. Repeated sprint speed endurance is important in team sports as players are often required to sprint under conditions of fatigue. Agility Agility is the ability to explosively stop, change direction and accelerate again. It encompasses movements in non- linear directions, e.g. backward, diagonal running etc, as opposed to just straight line speed. Agility is a crucial requirement in rugby and most team sports as movements more often than not are multidirectional. The player who can change his speed and direction the most effectively will more often than not prove superior. Agility is determined by the athlete's fast speed strength in all movement directions and the body’s neuromuscular co-ordination of the muscles involved. Active flexibility. This refers to the amount of movement you can actively produce around a joint. For optimal force production the body needs to be able to stretch to certain lengths so that the muscles are in an ideal position to produce the most force. A players active flexibility depends upon static flexibility and how warmed up the player is, e.g. you would have better active flexibility in the evening than the morning.