Strength & Power Testing for Athletes
Strength and Power testing is an issue that seems to concern sport scientists worldwide. Identifying the weaknesses of our athletes is the key element for their success. Similar to movement, weak links that may influence an athlete’s posture and consequently their performance, strength and power links need to be identified and further worked on through training. Therefore, training focus and strength needs for each athlete are different and have to be taken into account from coaches and S&Cs.
Let’s see the different ways for strength and power testing, from the simplest to the most complex, used by sport scientists.
Handheld Dynamometer
Handheld dynamometers are an easy way to have a representative image (as I like to describe it to my athletes) of the muscle imbalances between the two legs. There are some concerns regarding the validity and reliability of such dynamometers, but as recent studies have shown, handheld dynamometers have high correlation in terms of maximum strength testing with isokinetic dynamometry. We need to bear in mind that testers should be the same and use the same standard procedure, as to maintain the validity of our results.
So, in summary, handheld dynamometry:
- Is cost effective
- Is easy to perform
- Compared to isokinetic dynamometry, has a high correlation for hamstring and quadriceps torque
- Requires a consistency in the tester and the testing procedure to ensure valid results.
Isokinetic Dynamometry Testing
There are a lot of debates regarding the use of isokinetic dynamometry. I consider this a useful way of testing, in terms of rehabilitation or a more detailed image of an athlete who might have issues with muscular imbalances or past injuries. The fact that a lot of teams are using isokinetic dynamometry for testing – especially at the beginning of the season – has me wondering if it is that important in terms of general screening?
- Main application is in assessing hamstring to quad ratio
- Reliable and valid results, standard procedure
- Seated position to assess muscle function of the knee. Researchers suggest for testing prone position (10o hip flexion) which simulates hip joint angle in running position.
- Quite pricey
- Time consuming
Force Plate use in Testing
All movements in sports are better understood by examining the forces involved when they are performed. For example, data of the forces applied to the ground in a vertical jump provide a picture of an athlete’s explosiveness. Ground Reaction Forces (GRF) have been shown to have moderate relationships with other strength and power tests such as back squat or 1 repetition maximum, or even performance tests for agility or sprints. On the other, it should be better to use GRF to differentiate high level and senior athletes. Lately, sport scientists in order to have a good picture of the their athletes’ performance abilities, they evaluate variables related to maximal strength, isometric rate of force development and explosive performance in static and countermovement jumps with a variety of loads.
What makes the force plate use so special is the example of how vertical jump height is often used as a performance marker of explosive ability. While jump height is an important measure, it is not necessarily detailed enough to show differences between jumps. That means jumps with the same height may have a difference in peak force, rate of force development, impulse and so on. Moreover, take off or landing forces should provide the coach with a better understanding of the athlete’s mechanics and strength imbalances between the legs. From my own experience, the information one could take from a test on a force plate is vast, but you have to be very strict with the test procedure and test interpretation to take useful results.
- Abundance of information regarding an athlete’s explosiveness
- Imbalances between the two legs in take off or landing phase
- Accurate and reliable results
- Neuromuscular control (studies involved fatigue index)
- High cost
- Requires a sports scientist, specially trained to perform the tests
Repetition Maximum
A simple Repetition based formula for discovering 1 Rep Max in strength exercises developed by Boyd Epley and presented in 1985 is(Load x Reps x .033) + Load= 1 Rep Max.
Recent technology introduced accelerometers that can help coaches find 1RM with sub maximal effort taking into account the velocity and the power of each exercise performed. Personally, I am using a number of these devices (GymAware, Chronojump, Push) and I found them useful for determining 1RM and also for coaching and monitoring athletes in a strength training session. As we know, velocity and power are the key elements for developing an athlete, so its important to have feedback and coach our athletes according to their needs.
- Important to prescribe a strength training program
- Does not require the use of an accelerometer, easy to perform (no equipment needed)
- With an accelerometer, trained personnel is required and has a high cost
Conclusions and General Thoughts
1. Strength, Power and Speed are the key elements for an athlete to develop. All strength & conditioning coaches are looking for the ideal programs to train these aspects. In order to have better results, they have to take numbers from the sports scientists or even create their own testing, so they will have a better picture of their athletes’ needs
2. Use, in a consistent manner, the same tests and have comparisons for your athletes in a period of time. Create your own norms and assign goals for them. Athletes are more likely to work harder when they are challenged or when they have a target. Just focus on their needs.
3. Make your training programs simple and with progressions. Do not get caught up with complex programs and exercises that may confuse you and your athletes. Always have data to show and set achievable goals.
4. Always ask for feedback from your athletes and be ready to adjust your programs to their needs. Don’t stay in a well designed program that may not suit your athlete’s needs in practice.
References
Beckham G, Suchomel T, and Mizuguchi S. Force Plate use in performance monitoring and Sport Science testing. New Studies in Athletics, 29:3; 25-37, 2014
EXOS performance specialist online course, Strength Testing
Paul D & Nassis G. Testing strength and power in soccer players: The application of conventional and traditional methods of assessment. Journal of Strength and Conditioning research, 29 (6): 1748-1758, 2015.
Whitely,R, Jacobsen, P, Prior, S, Skazalksi C, Otten, R, and Johnson, A. Correlation of isokinetic and novel hand-help dynamometry measures of knee flexion and extension strength testing. J Sci Med Sport 15(5): 444-450, 2012.