Bilateral vs Unilateral Training for the High Performance Athlete

Any high performance athlete or person with-in that field, knows the importance of an appropriate training programme, from which the athlete will experience the most development growth (Amercian College of Sports Medicine, 2009) . Two forms of training protocols, which have come into much discourse in the sporting world are bilateral and unilateral training.

First off what’s the difference?

Unilateral  is a style of training when the athlete uses only one limb at a time and although many would say they ‘don’t do this’, every time you walk or run you’re performing a unilateral movement.

 

To make it simple, an example of a gym based unilateral movement is a single leg deadlift or a single arm dumbbell press. Generally unilateral training is overlooked and bilateral training (working both limbs at a time) is favoured. Training one limb at a time allows an athlete to focus on the stabilising joint muscles, thus preventing injuries and improving functional movement, for an athlete by allowing prime movers to dominate work load.

Bilateral Training

More stability is recruited when training bilaterally which is essential for an athlete to build more strength (Caleb, et al.2014 and Yoshioka, et al. 2011) . More tension is required when building strength therefore, any exercise that requires too much coordination, balance or agility (many unilateral) can cause an athlete to concentrate too much on those factors and limit tension in the large muscles (Song et al. 2014) .

Many argue that bilateral training should be favoured because your body generally uses both limbs for most heavy activities. such exercises do require less skill which will increase tension in a muscle, providing more strength stimulus. However high performance athletes should have an honourable skill level, so should they be training unilateral?

Training Goals

Its clear that the advantage of unilateral training is an athlete will have more freedom over movements and can lessen the load on some joints, causing stabilisers to work harder. So if an athlete strives for strength, a bilateral approach seems to be favoured. (Campos, el al, 2013)

Most standard strength competitions or tests seem to be focus on bilateral forms of movement. Olympic lifting consists of the clean and jerk and the snatch, both bilateral movements. Powerlifting consisting of squat, deadlift and bench press, again all bilateral using a barbell. Bilateral exercises will therefore, give the athlete a greater transfer to performance.

It has been documented that if an athlete trains predominately bilaterally, they could transfer to a unilateral training programme with greater ease, for example an athlete could squat hundreds of kilos successfully, but when asked to perform a one-legged squat they fail (Golik-Peric, et al. 2011 and Jakobi, 1998).

The Bilateral Deficit

During maximal contractions, the sum of forces exerted by homonymous muscles unilaterally is typically higher than the sum of forces exerted by the same muscles bilaterally. However, the underlying mechanism of this phenomenon, which is known as the bilateral strength deficit, remain equivocal (Simoneau, et al. 2015). So if an athlete produces a maximum force bilaterally, this force will be less than two single limbs working individually. For example, if you could do a single arm dumbbell curl with 20 kilos in each had but could only bench press 30 kilos, this is bilateral deficit. However most studies that document this, show evidence with weighted machines that high performance athletes generally wouldn’t use (Beckham G, et al.2013). Studies show that with training the deficit usually decreases, or even goes altogether (Sato K, et al. 2013).

The High Performance Athlete

Every athlete has individual needs that their training problem has to address, the debate on bilateral vs unilateral for a high performance athlete is not a straight set debate. Extrinsic and intrinsic factors also have to be taken into consideration such as:

• The athletes sport
• Individual weaknesses
• Previous injuries
• Skill level
• Training time available
• Goals

If an athlete has or is injured or has a weakness in one limb compared to the other, a unilateral approach to training may provide the athlete with stability and rehabilitation to progress, however unilateral training alone in a high performance athlete doesn’t produce a strength programme elite enough to transfer to performance on its own (Weir, 1997)

The Bottom Line

For any athlete to improve athleticism , a neurological carry over from strength training to explosive movements must be present. While unilateral movements have a place, most research suggests that bilateral training has the best ‘carry over’ to performance. Take a sprinter, if they perform a triple extension during a bilateral lift they can transfer this power and speed to sprinting. A sprinter performing cleans, squats, deadlifts and snatches will hit triple extension, thus improving their sprint and jump performance. Take a sprinter that performs unilateral movements such as one-legged squats, deadlifts etc they simply wont be able to transfer the movement as efficiently. A unilateral squat takes time to perform an athlete must build up of neural drive. Whereas an athlete that performs a unilateral movement within their sport (ground contact time, within a long jump) is very quick. The ‘carry over’ between the two means disconnect between the two is greater. Training slow when you perform fast, warrants research to determine it’s success.

References

American College of Sports Medicine, 2009 American College of Sports Medicine position stand. Progression models in resistance training for healthy adults. Mar;41(3):687-708. doi: 10.1249/MSS.0b013e3181915670.

Beckham G, Mizuguchi S, Carter C, Sato K, Ramsey M, Lamont H, et al. Relationships of isometric mid-thigh pull variables to weightlifting performance. J Sports Med Phys Fitness 2013 Oct;53(5):573-581.

Bilateral Strength Deficit Is Not Neural in Origin; Rather Due to Dynamometer Mechanical Configuration.PLoS One. 2015; 10(12):e0145077. Epub 2015 Dec 16.

Campos G, Luecke TJ, Wendeln HK, Toma K, Hagerman FC, Murray TF, Ragg KE, Ratamess NA, Kraemer WJ, Staron RS 2013. Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones. Nov;88(1-2):50-60. Epub 2013 Aug 15.

C D. Bazyler, C A. Bailey, CY Chiang, K Sato, MH Stone. 2014 Journal of Trainology. The effects of strength training on isometric force production symmetry in recreationally trained males. Vol. 3, No.1, p.6-10

J.M. Jakobi and E. Cararelli, 1998. Neuromuscular drive and force production are not altered during bilateral contractions. J Appl Physiol 84: 200-206.

Simoneau-Buessinger E, Leteneur S, Toumi A, Dessurne A, Gabrielli F, Barbier F, Jakobi JM.

Song Y, Forsgren S, Liu J, Stål P. 2014 Unilateral muscle overuse causes bilateral changes in muscle fiber composition and vascular supply. Dec 29;9(12):e116455. doi: 10.1371/journal.pone.0116455. eCollection 2014.

Weir JP, Housh DJ, Housh TJ, Weir LL. 1997 J Orthop Sports Phys Ther. The effect of unilateral concentric weight training and detraining on joint angle specificity, cross-training, and the bilateral deficit.  Apr;25(4):264-70.