Hamstring Eccentric Strength Development: Nordics or Razors?
When attempting to develop hamstring eccentric strength, the Nordic hamstring curl and hamstring Razor curls have been shown to both be very similar exercises, which target, develop and activate hamstring strength (1). They both are essentially the go-to hamstring exercises that focus on eccentric contractions to develop hamstring strength, but are also heavily used in the S&C and Allied Health field for the prevention or rehabilitation of hamstring injuries. The key difference between the 2 exercises though, is the motion in which a person’s hip goes through and the direction the body moves through to complete the exercise.
Nordic hamstring curls have been seen to improve hamstring strength by 11% after a 10 week program (6). They’ve been implemented in a study by (Peterson et. Al, 2011) which concluded that Nordic hamstring curls in fact decrease the overall, new and reoccurrences of hamstring injuries (5, 7). The exercise requires a person to have their feet supported or strapped down whilst they’re simply on their knees in an upright position. Ensuring their body stays straight; they lean forward and lower themselves attempting to resist the fall to the ground, eccentrically contracting the hamstrings. The point at where the person can no longer resist to gravitational pull effectively is an assessment of their hamstring eccentric strength (6). This exercise is clearly demonstrated in the study by (Sconse et. Al, 2015).
Razor curls are slightly different to Nordic curls. The Razor curl is designed to increase hamstring contractibility by placing the hip into flexion (3). Instead of being in a straight upright position, like the Nordic curl, Razor curls require the individual to have there body at 90 degrees to there hips (leaning forward). Effectively, whilst on their knees and having their feet supported, the person will move themselves forwards and backwards, eccentrically contracting their hamstrings. A clear example is shown in the studies by (Oliver and Dougherty, 2009) (3, 4).
Both of these methods serve their purpose to develop hamstring strength, and there is a substantial amount of evidence to support their contribution to hamstring injury reduction. However, in my opinion, I tend to encourage individuals to choose the Nordic hamstring curl, over Razor curls, for a number of reasons.
Firstly though, Nordics and Razors are so simplistically effective, in that they can almost be performed anywhere, anytime. They’re much easier to implement in a group setting with a number of athletes or clients, and, instead of purchasing equipment or machines designed to train hamstrings in isolation, it costs nothing to perform them (all you need is a friend or something heavy to lock your feet under).
Nordics, however, have been proven to be a more effective exercise than traditional hamstring curl exercises on machines (2), and are also beneficial in preventing hamstring injuries, further having shown to reduce the risk of re-injuring a previously damaged hamstring (2, 5-7). Nordics have also been shown to have the greatest hamstring eccentric muscle activation (1).
When we also break down the pattern of both exercises, (as explained above) it’s clear that the initial movement of a Razor Curl utilises a greater glute/ham complex from the hip flexed starting position. This in turn actually makes it a more difficult exercise to execute for most people, leaving (in my opinion) Nordics a clear winner.
But, just like anything, both exercises can, and do, serve a purpose in an athlete’s or clients program, and should not be solely used to develop overall hamstring strength. Other exercises such as; the Romanian Deadlift, Stiff Leg Deadlifts, Straight Knee Bridges and Single Leg Arabesques can all be utilised and/or rotated throughout a persons program to target and develop the entire hamstring (and glute) complex.
REFERENCES:
Bourne MN, Williams MD, Opar DA, Al Najjar A, Kerr GK, and Shield AJ. Impact of exercise selection on hamstring muscle activation. British journal of sports medicine 51: 1021-1028, 2017.
Mjolsnes R, Arnason A, Osthagen T, Raastad T, and Bahr R. A 10-week randomized trial comparing eccentric vs. concentric hamstring strength training in well-trained soccer players. Scandinavian journal of medicine & science in sports 14: 311-317, 2004.
Oliver GD and Dougherty CP. Comparison of hamstring and gluteus muscles electromyographic activity while performing the razor curl vs. the traditional prone hamstring curl. Journal of strength and conditioning research / National Strength & Conditioning Association 23: 2250-2255, 2009.
Oliver GD and Dougherty CP. The razor curl: a functional approach to hamstring training. Journal of strength and conditioning research / National Strength & Conditioning Association 23: 401-405, 2009.
Petersen J, Thorborg K, Nielsen MB, Budtz-Jorgensen E, and Holmich P. Preventive effect of eccentric training on acute hamstring injuries in men's soccer: a cluster-randomized controlled trial. The American journal of sports medicine 39: 2296-2303, 2011.
Sconce E, Jones P, Turner E, Comfort P, and Graham-Smith P. The validity of the nordic hamstring lower for a field-based assessment of eccentric hamstring strength. Journal of sport rehabilitation 24: 13-20, 2015.
Thorborg K. Why hamstring eccentrics are hamstring essentials. British journal of sports medicine 46: 463-465, 2012.