Background

With the advancements in the playing surface and rulings in field hockey it has meant that the game has become increasingly popular due to its high speed and intensity (Sunderland et al, 2006), therefore the step between regional club playing standard to national league standard has grown. To attempt to bridge this gap the following coaching resource will be aimed at improving lower body power through resistance training, for individuals that have little or no experience with resistance training.

Resistance training, or strength training, is an effective and established way of improving muscular performance (Bird et al, 2005). Kraemer (2002) described the main goals of resistance training as improving muscular strength, power and endurance, with other health benefits such as increase bone mass, lower blood pressure and increase muscle and connective tissue cross sectional area (CSA). 

Power can be measured as:

 (Williams & James, 2001) 

Cormie (2011) stated that maximal muscular power is defined and limited by the force-velocity relationship, and an athlete with high power can create great forces in small periods of time.

Figure 1. Force vs Velocity curve with Power Maximum plot. (Cormie et al, 2011)

As this resource is focused on individuals with limited resistance training backgrounds, basic techniques need to mastered before increasing the load on any exercise, however once techniques are in place, the athlete will be focusing on working in the bottom right region of the force/velocity curve (shown below), improving strength to have a positive impact on power.

Figure 2. Force vs Velocity curve with Power Maximum plot (Cormie et al, 2011), showing strength increase.

Field hockey is a physically demanding sport and in the modern game, for outfield players, the majority of the playing time is spent at above 75% of heart rate maximum (Sunderland et al, 2006). A study from Lythe and Kilding (2011) discovered that on average elite hockey players changed speed, between 6 different speed zones, every 3.65 seconds in a competitive game, which is similar to that of a professional football player. Newton and Kraemer (1994) commented that power is essential in changing direction and acceleration in a variety of sports, therefore if power is improved, the athlete will be able to accelerate faster and turn sharper, giving them an advantage over opponents.

Requina et al (2011) found a strong positive correlation between high one repetition maximum (RM) squats, high counter movement jump scores (CMJ) and low 30 meter sprint times in male sprinters, showing strength as well as power training can benefit sprint speed (Spinks, 2007). 

Physiological Rationale

When carrying out resistance training, an athlete will experience many physiological adaptations as a result of overloading the skeletal muscular system. Referring back to the force-velocity relationship for power club level athletes need to be initially focusing on increasing force (strength), then after a solid foundation move onto increasing the velocity (Cormie et al, 2011). Ronnestad and Hansen (2011) found that a 12 week strength training period in well trained cyclists increased squat jump power test results by an average of 13% pre to post.

Figure 3. Pre -post squat jump test results in independent groups. (Ronnestad and Hansen)

Cormie et al (2011) discussed how the force produced by muscles decreases as velocity is increased, so specified strength training should be carried out under a low velocity however the contractions should still be isotonic to help the progression to power training.

Why is the Force vs Velocity relationship so important?

Due to the force of a muscle being determined by the number of cross bridges attaching, increases in velocity results in less cross bridges being able to connect, therefore less force due to the length of the sarcomere, this is also known as the length – tension relationship   (Leiber et al, 1994).

A further factor in the force velocity relationship is the cross sectional area of the muscle (CSA) and fibre type. The larger the CSA of the muscle, the more single fibre strands available to contract and provide more force (Cormie, 2011), however the type of muscle fibre has a vast effect on the strength of the athlete. Type IIa muscle fibres (fast twitch) have the greastest hypertrophy ability followed by IIb (Bird et al, 2005; Stone et al, 2006). Previous studies have shown up to 45% of muscle fibre type is pre-determined by genetics (Simoneau and Boucard, 1995), however Hedrick et al (2008) looked at how type IIb fibres could be enhanced through resistance training to gain type IIa traits, therefore increasing an athlete’s CSA of type IIa fibres, increasing strength and power.

Muscular architecture is another area determining the strength of an athlete, Clark et al (2006) found that the thickness of the medial head of a muscle predicted the isometric and isotonic force produced, the thicker the muscle, the greater force produced. The pennation angle is the angle between the line of action and the muscle fascicles (Cormie 2011). In low velocity resistaance training when pennation angle increases, muscles are able to work nearer their optimum length with reference to the length-tension relationship, therefore generating more force (Cormie, 2011). 


Biomechanically increased strength will allow the production of greater force, resulting in decreased contact time, leading to a possible increase in stride frequency which will improve acceleration (Spinks et al, 2007). Hockey players with faster acceleration stand more chance of losing their marker, or reaching the ball first to gain possession for their team.

Image 1, Strength in Field Hockey.

Exercise Techniques

All exercises should be carried out in risk free environments, wearing appropriate footwear, clothing and completing a warm up set for each exercise to reduce the chances of injury.

As previously stated, athletes with little resistance training should start by gaining knowledge and neuromuscular feedback for the correct techniques and maintaining form through the duration of each or the exercises (Cormie, 2011). Athletes should start by attempting to use their own body weight as an indicator of their initial strength, adding weighted medicine balls as a progression, then moving onto barbell exercises (Hedrick et al, 2008; Whaley et al, 2006)

Specificity is vital when prescribing athletes exercises, making them sport or movement related to gain to best training effects (Ronnestad and Hansen, 2011; Spinks et al, 2007). To focus on strength with benefit to hockey, exercises need to involve similar triple extension actions to that of sprinting, extending the hip, knee and ankle from flexed positions to apply force to the ground (Spinks et al, 2007). 

Image 2,Triple Extension, from sprint start.

The Front Squat

Image 3, Medicine ball front
squat set position.

The front squat is one of the most common lower body exercises, that can directly relate with sporting movement for hockey. The athlete starts either with just body weight, or a medicine ball held and chest height directly out in front of them with extended arms.


The athlete should keep their weight on their heels through the duration of the squat, pointing their toes up.


The athletes back should be straight and strong, NOT allowing their shoulders to roll or hips to tuck under.

Image 4, Medicine ball front
 squat down phase

The athlete should then attempt to lower themselves, as if sitting down on a chair.

During the down phase the back should stay strong, and the hips, knees and ankles should all flex.

The motion should be slow and controlled, with both knees staying constantly stable.

To progress the front squat and add load, introduce the barbell when the athlete is comfortable with medicine balls.

Do not add weight initially, just use the bar.


The technique is the same with the medicine ball, although elbows should be facing forwards and pointing as high as possible, resting the bar on the chest, this becomes more vital with heavier load.

Image 5, Barbell front squat set position.


The front squat boasts triple extension, and is an easy way of  keeping track of an athletes lower body strength. If the technique of a body weight squat is initially assessed, a coach may be able to diagnose problems such as less flexible muscle groups, or weaker areas of the muscular system, and put methods in place to overcome them (Hedrick, 2008)

Image 6, Barbell  back squat
 down phase.

To increase the load further, a back squat can be introduced as weight is more comfortable to bare on the top of the back, allowing greater resistance, thus more force needed to be produced.

The Split Squat

Image 7, Medicine ball split
 squat set position.

The split squat is still a double leg triple extension exercise, however the rear leg is behind the center of mass, replicating more of a acceleration drive phase action.


The athlete can imagine their body is on a vertical axis, moving the load straight up and down, NOT allowing their leading knee to move over the foot and hyper extend the ankle.

Image 8, Medicine ball split
 squat down phase.

The down phase is done under control, and the load must be kept stable by the core muscles, NOT allowing the exercise to become unbalanced.

Image 9, Barbell split squat
 down phase.

To progress the split squat a barbell can be added, carried on the back, with all the same principles and techniques as above. Emphasis must be kept on keeping stable and controlled when load is increased.

The Deadlift

Again the deadlift is a lower body exercise containing triple extension, relating directly to sporting movements such as sprinting a jumping (Classman, 2003). The techniques required with deadlift are very important to prevent lower back strain.

Image 10, Barbell deadlift
 set position.

Natural stance with feet under hips, shoulder width apart. Symmetrical grip on the bar with hands placed where arms won’t interfere with legs while pulling from the ground. The bar should be above the juncture of little toe and foot, with shoulders slightly forward of bar. Core muscles should be tight with arms locked and not pulling on the bar, shoulders must be pinned back and down with latismuss dorsi and triceps contracted and pressing against one another.

Image 11, Barbell deadlift
 lock out phase.

Weight should be kept on the heels of the athlete, keeping the bar close to the legs, essentially the load moves on a vertical axis. The head needs to be looking straight ahead ensuring shoulders and hips rise at same rate when bar is below the knee. Arms remain perpendicular to ground until lockout.

A progression from deadlift is the straight leg deadlift, which focuses on hamstring resistance, cutting out the flexion and extension of the knee and ankle joints.

Image 12, Barbell straight leg
 deadlift down phase

In straight leg deadlift the inital pick up and lockout are the same, however the down phase consists of lowering the bar down, with a locked straight back and pulled back shoulders, to as far down as possible without putting the hamstrings under too much strain, then lifting the weight back up by extending the hips.

Guidelines and Prescriptions

Some guidelines have been discussed within this blog, however it is essential for athletes to only progress to exercises involving higher resistance once they have mastered the technique for the previous exercise, so for example going from body weight squat, to medicine ball front squat then onto barbell squats. These steady progressions will build up a solid base to avoid strains and injuries.


With regards to club levels hockey players, when first attempting any new exercise they should focus on sets with high repetitions and low loads, purely to master techniques. From there players can increase the loads and decrease the number of repetitions. When the players level of strength has increased to the standard of being able to squat around 1.5 x body weight (Cormie et al, 2011), they can progress on to more specific power training. Newton and Kraemer (1994) found that athletes with a solid base of strength training struggled finding power improvements when carrying out further strength training, suggesting that strong athletes need to progress onto more specific power programs, increasing the velocity in their training.


If a club level hockey player is able to improve their lower body strength through the exercises above, they will:

• gain a base of strength, increasing their power (Stone et al, 2006)
• gain muscular and tendon hypertrophy, reducing injury risks (Hedrick and Wada, 2008)
• be able to apply more force to the ground and decrease contact time, improving sprint speed and acceleration (Spinks et al, 2007)

All these improvements give a club level player the opportunity to go onto more advanced power training, and allow them to be physically stronger and faster than opposing players, which therefore starts to bridge the cap between the club level player and national league player.

Image 13, Team Adidas England Hockey, 2010.

References

Bird, S.P., Tarpenning, K.M & Marino, F.E. (2005) 'Designing Resistance Training Programmes to Enhance Muscular Fitness' Sports Medicine. 35 (10), pp 841-851.

Clark, R., Bryant, A., Humphreys, G.C. & Hohmann, E. ‘The relationship netween muscle architecture and performance’. Central Queensland University, Australia; 1: 1-16.

Cormie, P., McGuigan, M.R. & Newton, R.U. (2011) ‘Developing Maximal Neuromuscular Power, Part 1 – Biological Basis of Maximal Power Production’, Sports Medicine, 41 (1), pp. 17-36.

Cormie, P., McGuigan, M.R. & Newton, R.U. (2011) ‘Developing Maximal Neuromuscular Power, Part 2 – Training Considerations for Improving Maximal Power Production’, Sports Medicine, 41 (2), pp. 125-146

Glassman, G & Glassman, L. (2003) 'The Deadlift’. CrossFit Journal. 12 (1), pp. 1-3.

Hedrick, A & Wada, H. (2008) ‘Weightlifting Movements: Do the Benefits Outweigh the Risks?’ Journal of Strength and Conditioning. 30 (6), pp. 26-34.

Kraemer WJ, Ratamess NA, French DN. (2002) ‘Resistance training for health and performance’. Curr Sports Med Rep 2002; 1: 165-71.

Lieber, R.L. (2010) Skeletal muscle structure, function and plasticity: the physiological basis of rehabilitation. 3^rdEdition. Philadelphia: Lippincott Williams & Williams.

Lythe, J & Kilding, A.E. (2011) 'Physical Demands and Physiological Responces During Elite Field Hockey' International Journal of Sports Medicine. 32 (7), pp. 523-528.

Newton, R.U & Kraemer, W.J.(1994) 'Developing Explosive Muscular Power: Implications for a Mixed Methods Training Stratergy' Strength and Conditioning. 4 (1), pp. 19-31.

Ronnestad, B.R., Hansen, E.A. (2011) 'High volume of endurance training impairs adaptation to 12 weeks of strength training in well-trained endurance athletes' European Journal of Applied Physiology. 112 (1), pp 1457-1466.

Simoneau, J.A. & Boucard, C. (1995) ‘Genetic determination of fiber type proportion in human skeletal muscle’The FASEB Journal, 9, pp. 1091-1095.

Spinks, C.D., Murphy, A.J., Spinks, W.L & Lockie, R.G. (2007) 'The Effects of Resisted Sprint Training on Acceleration Performance and Kinematics in Soccer, Rugby Union, and Australian Football PLayers' Journal of Strength and Conditioning Research. 21 (1), pp77-85.

Stone, M. H., Stone, M.E., Sands, W.A., Pierce, K.C., Newton, R.U., Haff, G.C & Carlock, J. (2006) 'Maximum Strength and Strength Training - A Relationship to Endurance?' Strength and Conditioning Journal. 28 (3), pp 44-53.

Sunderland, C., Morris, J.g & Leslie, V. (2008) ‘Physiological and Performance Characteristics of Female Hockey Players’. Medicine and Science in Sports and Exercise. 40 (5), pp. 384-384.

Williams, C.A. & James, D.V.b. (2001) Science for Exercise and Sport. 1^st Edition. New York: Routledge. Pg 71.