If you play netball in Brisbane you are almost entering your preseason phase before the 2021 season commences. Pre-season is a crucial part of any team or individual sport. Preseason ensures that you as an individual, are priming the body to reach your peak to be able to perform at your best during the season, but ultimately you are trying to bulletproof your body to avoid injuring yourself. In netball the most common injuries are ankles and knees and therefore it is of high importance to train with a focus on strengthening the lower limb, not only to protect the body, but to enhance performance in common skills required such as vertical jump, both acceleration and deceleration, landing and changing direction.
Given the fast pace of the game of netball and the rule restriction of not being able to run with the ball, players leap and bound often with the addition of trying to evade opposing players and positional restrictions on court, this can result in random or abrupt deceleration and landing. The nature of explosive jumps, abrupt landings and deceleration creates an incredibly high level of ground reaction force (GRF) on the lower body. Studies have shown that netballers who replicated the movements of a game in a laboratory experiment produce 2.4-5.7 times their body weight for a vertical GRF when landing and 2.0-4.6 times body weight for GRF in a horizontal land or abrupt stop. If you combine these hazardous levels of GRF with an incorrect landing mechanism there is a high probability of causing serious injury.
The most common injury in netball is to sprain the ankle (approx. 84% of injuries) with up to 67% of those being a lateral or inversion ankle sprain. This may be due to the high volume of jumping, landing and pivoting to change direction demanded by the sport. All of these movements leave the body susceptible to a rapid shift of centre of mass over the landing or weight-bearing foot. This creates a forceful combination of plantar-flexion and inversion, causing the ankle to roll outwards while the foot turns inwards causing a consequential stretch or a tear of the lateral ligament.
Anterior cruciate ligament (ACL) ruptures are the most
frequently reported knee injury to netball players. There are two common scenarios that increase the risk of ACL injuries; when a player receives a perturbation (knock) when jumping in the air to receive or attempt to intercept a pass- resulting in an unstable landing. The other mechanism is a rotational and lateral flexion of the trunk relative to the foot alignment before completing a landing movement. The fact that a large portion of landing in netball occurs with a unilateral (single sided) landing mechanism increases the probability of
injury. Research suggests that females are more susceptible to having more knee valgus or medial tracking of the knee (an inwards ‘collapse’ of the knee). This is thought to be due to a female often having a larger Q angle; this is the angle measured between the quadriceps muscle and the patella tendon (using the anatomical points of the ASIS of the hip to the mid-point of the patella and the tibial tubercle). This, coupled with an increased GRF produced when landing may explain some of the mechanics behind the increased rate of ACL injuries in netball.
Preseason training is not just about endless amounts of running trying to smash the players every session, they need to target both cardiovascular and strength components in their training. Strength in pre-season is exceptionally important to assist in reducing any muscle strength asymmetry (MSA) to reduce the risk of acquiring these injuries. It has been reported that a strength discrepancy of anything more than 10-15% asymmetry between limbs is considered to be a significant difference and may start to effect skill performance and execution. There has been an association linked between larger MSA’s and lower jump heights and lower peak power in loaded or unloaded jumps. It has been demonstrated that athletes with a high relative strength are likely to have a significantly faster sprint time and higher countermovement jump performance. An athlete who exhibits greater strength levels will be able to produce a higher propulsive GRF during actions such as jumping, accelerating and change of direction. In addition, a greater maximum relative strength will result in lower levels of MSA and consequently a higher production and acceptance to GRFs on both limbs for those movements. This will improve netball performance due to its nature of having high repetitions of unilateral jumps, landings and the unpredictability of change in direction all completed at a high intensity. This highlights the importance of not only training the skill specific properties of netball but having an overall stronger body to assist in performing these skills and assist in reducing injuries.
Another important key factor to consider when developing a strength and conditioning program for a netballers pre-season is the amount of cardiovascular fitness they require to be able to replicate the demands of the sport in season. Each game of netball lasts for a total of 60 minutes, so it would be easy to consider that netballers need to focus on their aerobic endurance. But within that 60 minutes it is reported that professional netballers will execute a change in activity pattern on average every 6 seconds. Meaning they are accelerating, decelerating and changing in direction frequently, and completing anaerobic efforts such as bouts of running and sprinting 25-202 and 5-81 times respectively. This can tally up to 143-1758 meters of running or 69-555m worth of sprinting in one game. Bearing in mind the high frequency of change in direction as well as considering the court positional restrictions and the critical need of evading opposition players, the players will be prevented from reaching their peak velocity on court often. To do so would require the athlete not only effective change in direction skills, but a fast acceleration and sprint speed, both of which can be increased through strength training.
Below is a table outlining the general components that need to be considered when developing an S&C program for netball players. To begin pre-season there will be a focus on developing general baseline fitness both strength and cardiovascular.
Begin by ensuring the player is covering the total requirements of the game – either in distance or time, then progress to increasing intervals and intensity required for the repeated bouts of effort with minimal rest as replicated in the sport. This will improve the aerobic endurance and anaerobic fitness and increase the body’s ability to uptake and utilise proficiency. The level of cardiovascular fitness each player should reach will be different based on positional requirements, for example; a (C) player who runs up and down the full length of the court in comparison to a GS or GK who is only allowed in a third of the court. Centres demonstrate a quicker 5 or 10m sprint in comparison to shooters- this is thought to be due to the increased repetition that is completed during a game.
Regarding overall muscular adaptations and extensive strength program should encompass whole body strength with an emphasis on lower limb strength as this will assist in injury prevention, stronger legs and enhance a player’s ability to complete skills in the game such as vertical jump, sprint or change in direction. Remembering a focus on reducing MSA should be incorporated! After this the focus should shift to increasing stability and landing mechanics, not only will this assist in reducing knee valgus but will highly correlate to match play. There should be progressions from bilateral to unilateral balance and landing including progressions to multidirectional landing to ensure the skills transfers to netball. Following on from this there will be a focus of force production through power and plyometric training, emphasising minimal time in contact with the ground and the ability to absorb and reproduce force quickly
Components of agility and change of direction need to be included in a program as we have already discovered in the previous blog, how frequent and important this skill is for netball. Faster change in direction are strongly associated with shorter ground contact times, greater horizontal propulsive forces and greater horizontal braking forces. This will be achieved both through gym based exercises and working on footwork and coordination and can often start to incorporate skills as well – e.g. bringing the ball in to the drill
Throughout the season this training program will change to become a combination of these styles of training. There will also be the addition of agility, coordination and skill based training into their programming. Lastly it is important to consider the players’ overall load, when taking into consideration skills training throughout the week and game day. It is therefore critical to have a day where rest and recovery is included – this may be total rest, a light walk, stretching or other methods of recovery e.g. remedial massage.