The 5-7 repetition option will provide the most accurate representation of maximal voluntary strength/1RM. The greater the number of repetitions used, the more factors are involved in order to sustain adequate force production to lift a given load. A study by Reynolds, Gordon & Robergs (2006) found 5RM testing to be significantly more accurate when predicting 1RM strength when compared to 10 and 20RM testing groups.

Prediction of one repetition maximum strength from multiple repetition maximum testing and anthropometry - This should help.

Jon Mallon's answer is great!

Predicting 1RM isnt exactly an exact science. The best way to determine 1RM is to get the person to do 1RM. I've noticd that determining 1RM from 5 or 10 reps is dififcult, but determining what their 5-10 rep range is from their 1RM is much easier.

Hope this helps!

Hi Mr. Garavito

I found some references that I think can help you. So, I agree with John Mallon, the 5 - 7 repetition should provide the most accurate representation of maximal voluntary strenght/1Rm, however many factors are involved (e.g, group of volunteers,  anthropometry, morphology). These articles  address other exercises, however, inside them you will find many others publications, including to the leg extension. 

I hope this help you!

 thx to everyone , if you have more articles can send me :D

im new in this group, so i dont know how say thank you to each person, but really thx , i have more articles, if you need, and if in yours university you have found more, i will be gratefull. 

thx

sorry for my english :(

Dear Jeferoson

The 1RM is considered the gold standard for muscular strength. Although it is possible to predict 1RM with submaximal repetitions tests, the equations used for prediction are specific for each exercise. Furthermore, such tests will always be approximations. The smaller the number of repetitions, the lower wil be the probability of error. That been said,  if it is not possible to use the 1rm test, the best option would be to use the 5 to 7 repetitions test.

I hope to help you

Amandio Geraldes

In theory: Start somewhere. Work your way up to 3 hard but clean (full range of motion) reps on your desired lift (effective on Squats, Deadlifts, OHP, Bench Press, Cleans, snatches, etc.). Then from there I would generally add 10% to that number (lbs.) and consider that an estimated one rep max. Once you get your "number", on your next training session get 60-65% of that number and hit 3 sets of 12 clean reps (example). After a month in this 60-65% range, it is best to create blocks that lead you up to shorter rep ranges and higher % (70-75,80,85,etc) and thus providing you with a more accurate 1RM down the road. As one of the members above stated, its not exact science (some days you will feel incredible than others). It is a skill and takes time to develop for an accurate 1RM test.

Hi Jeferson,

The closer to one the number of repetitions used in the test, the more accurate the load prediction for the 1-RM test.

I suggest reading Dohoney et al. JEPonline 2002.

Find attached

I think that for the very best way to predict is to know the aim of predicting whether to train bearing distinctive force or power or speed maximam power

While the test you are investigating is novel, the source for this type of information is the National Strength and Conditioning Association (NSCA). Most prediction equations have been devised for bench press, squat, and dead lift - the events in the sport of Power Lifting. The American College of Sports Medicine's journal Med Sci Sports Exerc has about 25 references but most are abstracts of poster or platform presentations but can be accessed at the ACSM site or through Medline. Here are 15 references from the NSCA's journal J Strength Cond Res from the 1992 to 2015.

Mann, JB, Ivey, PA, Stoner, JD, and Mayhew, JL. Efficacy of the National Football League-225 test to track changes in one repetition maximum bench press after training in National Collegiate Athletic Association Division IA football players. J Strength Cond Res 29(11): 2997–3005, 2015

Kelly, SB, Brown, LE, Hooker, SP, Swan, PD, Buman, MP, Alvar, BA, and Black, LE. Comparison of concentric and eccentric bench press repetitions to failure. J Strength Cond Res 29(4): 1027–1032, 2015

Bishop, A, DeBeliso, M, Sevene, TG, and Adams, KJ. Comparing one repetition maximum and three repetition maximum between conventional and eccentrically loaded deadlifts. J Strength Cond Res 28(7): 1820–1825, 2014

Benton, MJ, Raab, S, and Waggener, GT. Effect of training status on reliability of one repetition maximum testing in women. J Strength Cond Res 27(7): 1885–1890, 2013

Brechue, WF and Mayhew, JL. Lower-body work capacity and 1RM squat prediction in college football players. J Strength Cond Res 26(2): 364–372, 2012

Headley,SA, Henry,K, Nindl,BC, Thompson, BA, Kraemer,WJ, and Jones, MT. Effects of lifting tempo on one repetition maximum and hormonal responses to a bench press protocol. J Strength Cond Res 25(2): 406–413, 2011

Jidovtseff, B, Harris, NK, Crielaard, J-M, and Cronin, JB. Using the load-velocity relationship for 1RM prediction. J Strength Cond Res 25(1): 267–270, 2011

Iglesias, E, Boullosa, DA, Dopico, X, and Carballeira, E. Ana ´lisis of factors that influence the maximum number of repetitions in two upper-body resistance exercises: curl biceps and bench press. J Strength Cond Res 24(6): 1566–1572, 2010

Desgorces, FD, Berthelot, G, Dietrich, G, and Testa, MSA. Local muscular endurance and prediction of the 1 repetition maximum for bench press lift in different athletic populations. J Strength Cond Res 24(2): 394–400, 2010

Brechue, WF and Mayhew, JL. Upper-body work capacity and 1RM prediction are unaltered by increasing muscular strength in college football players. J Strength Cond Res 23(9): 2477– 2486, 2009

Mayhew, JL, Johnson, BD, LaMonte, MJ, Lauber, D, and Kemmler, W. Accuracy of prediction equations for determining one repetition maximum bench press in women before and after resistance training. J Strength Cond Res 22(5): 1570–1577, 2008

Reynolds, J.M., T.J. Gordon, and R.A. Robergs. Prediction of 1 repetition maximum strength from multiple repetition maximum testing and anthropometry. J. Strength Cond. Res. 20(3):584–592. 2006

Cummings, B. and Finn, K.J. Estimation of a 1 Repetition Maximum bench press for untrained women. J. Strength Cond. Res. 12(4):262 – 265, 1998

LaSeur, D.A., J.H. McCormick, J.L. Mayhew. R.L. Wasserstein, and M.D. Arnold. The accuracy of prediction equations for 1 RM performance in the bench press, squat, and dead lift. J. Strength Cond. Res. 11(4): 211 – 213, 1997  

Rose, K. and Ball T.E. A field test for predicting maximum bench press lift of college women. J. Appl. Sports Sci. Res. 6(2):103 – 106, 1992   

Hi.

The 5-7 repetition is more appropriate approach.

Hi Jeferson Stevens,

I agree with Jon Mallon and others when they said that the best way to predict 1RM load between the two options you give is the 5-7 range. 

As the number of repetitions increase, some physiological e psychological implications can induce the predicted 1RM to error, and it's more evident in sedentary individuals.

Best regards.

thank you everybody, i wanna know about the gold standar, many people say that 1Rm test is the gold standar, but the isocinetic dinamometer is the real gold standard?

For the test you describe, leg extension, you are correct that isokinetic dynamometry is the true Gold Standard. There are normative data for a wide range of persons from very young to very old, athletes, normals (non-athletes), males and females  By the nature of the device isokinetic dynamometer truly tests muscular strength. Power is the product of force multiplied by velocity (Power = Work/time = (Force x Displacement)/ time = Force x (Displacement/time) = Force x Velocity). The dynamometer only allows the movement to occur at the predetermined velocity, therefore the condition that is variable is Force.

An isokinetic dynamometer is the best way to measure Force, because it is the only thing that is allowed to vary in the performance of the movement. It also results in an assessment of only the musculature that produces the specific movement being studied, so for the quadriceps it is the best way to measure the maximal force producing capabilities of the four muscles. When using an isokinetic dynamometer, however, steps must be taken to insure the quality, validity, and reliability of the measures obtained.

The subjects must be trained to perform the movement because the "feel" of the exercise is unlike anything they will have ever experienced before and cannot be produced by any other exercise equipment. Therefore, it would be advisable to have one - three sessions for each subject, to acquaint them with the device (it will also provide you with data to ascertain the reliability and validity of your procedures). Since you are seeking to measure Maximal Strength, a minimum of three reps and a maximum of five reps would be advised; since the dynamometer will automatically report Peak Torque and tell you the rep on which it occurred. Also the desire to measure maximum strength will require the use of velocities of 60 deg/sec or less; and the values will vary depending on the velocity or velocities chosen (most normative data are for 300, 180, and 60 deg/sec). Whether you chose 3 sets of one velocity or 1 set at each of three velocities, it would be recommended to have an inter-set rest interval of 3 - 5 minutes. When using velocities of less than 60 deg/sec it would probably be better to limit each set to three reps because of the stress of the effort at those very slow velocities.