A SCIENTIFIC VIEW OF HAMSTRING EXERCISES

HAMSTRING MUSCLES AND THEIR FUNCTIONS

Before talking about hamstring exercises, we first need to know the muscles in the hamstring area and the functions of these muscles. Hamstring muscle group (semimembranosus, semitendinosus, biceps femoris long and short head) are three different muscles that start from the lower part of the pelvis, extend from the back and side parts of the femur, and connect to the upper parts of the tibia and fibula bones in the lower leg. The hamstring is divided into two parts; medial head (semimembranosus and semitendinosus), lateral head (biceps femoris long and short head). Its main function is to provide knee flexion. Among these muscles, only the short head of the biceps femoris has a function in the knee joint. Other parts have functions in both the hip and knee joints.

We should train the hamstrings with different sets, repetitions and rest intervals, just like other muscles. We should also give due importance to exercise diversity to work the muscles at different lengths.

Biceps Femoris

Bicep femoris starts from the pelvis and connects to the fibula bone. Its functions include flexion in the knee joint and external rotation of the flexed leg, as well as extension of the thigh.

Semimembranosus

It causes the leg to flex, and when the leg is in flexion position, it causes internal rotation and extension to the thigh.

Semitendinosus

It has the same functions as the semimembranosus muscle. It causes the leg to flex and when the leg is in the flexion position, it causes internal rotation and extension of the thigh.

Seated Leg Curl-Prone Leg Curl

Single-joint knee flexion (“leg curl”) is one of the most common exercises used to work the hamstrings because it isolates the target muscles using a weight machine, which stabilizes the body and prevents excessive joint movement. (one)

Seat leg curl and prone leg curl machines are frequently used in gyms. According to the research, both exercises are very effective in hamstring activation. (2)

Seated leg curls produced greater muscle hypertrophy than prone leg curls. The reason for this is the length-tension relationship. Since the hip is flexed during the seated leg curl performed in the sitting position, the muscles of the hamstrings crossing the hip joint are in an extended position. This situation contributes more to muscle development by allowing the hamstrings to be exposed to more tension during seated leg curls performed while sitting. (1)

Nordic Hamstring Curl Exercise

Nordic hamstring curl is an exercise that has become popular recently and is a little more difficult than other hamstring exercises. It is mostly preferred for rehabilitation after injury. A study has shown that Nordic hamstring (NH) exercise reduces the risk by increasing eccentric hamstring strength. (3) It is also the right specific exercise option for those who want to maximize the loading of the hamstring muscles in the eccentric phase.

Deadlift

Deadlift, Squat and Bench Press are basic resistance exercises performed in various training programs to improve physical fitness in athletes. This also explains the great interest in the study of muscle activation, which has translated movements into some of the most researched exercises in the current literature using EMG. (11th)

The deadlift exercise, in which the hip joint is predominantly used, includes a movement that can be transferred to daily living activities; It is also considered one of the largest compound movements because it involves the coordination of several muscle groups. It is a frequently performed exercise to develop lower extremity muscles, especially biceps femoris and semitendinosus and gluteus maximus. In addition, Deadlift consists of various variations. Sumo deadlift, hex bar (trap bar) deadlift, conventional (classic) deadlift, romanian deadlift, stiff legged deadlift, single leg deadlift. The traditional deadlift and its variations also appear to lead to high levels of hamstring EMG activation.

Sumo Deadlift

With a larger stance width and slightly narrower grip width for the sumo deadlift (SD) compared to conventional deadlifts (CD), there are differences in the amount of mechanical work and stress placed on various joints between SD and CD. For example, unlike the traditional deadlift, the sumo-style deadlift uses a significantly wider "finger span" stance that allows the arms to be placed inside the knees. The result is a narrower grip where the torso is significantly more upright before the lift and the bar is closer to the body during the lift, resulting in a reduction in joint moments and path forces. (4)

As a result of the research, hamstring activation in both movements is very close to each other. (5) These two exercises can be easily applied for hamstring activation.

Conventional Deadlift

Conventional deadlift is a variation of the traditional deadlift. This exercise, which is performed by slightly bending the knees and moving the hip joint back, has the same movement pattern as picking up any object from the ground. Barbell Deadlift provided the most hamstring activation compared to Hex Bar Deadlift and Hip Thrust movements. (6)

Single Leg Deadlift (SLDL)

The growing popularity of functional training has led coaches to call for greater use of unilateral leg exercises to comply with the training principle of specificity. One of these exercises is single leg deadlift. (7)-(8) Bicepes Femoris (BF), Gluteus Maxsimus (GMAX), Gluteus Medius (GMED)

Recent research shows that unilateral leg exercises can provide comparable or better training effects than similar bilateral exercises. Concentric EMG activity of gluteus maxsimus and BF was higher in SLDL than in DL. For GMED, BF, and GMAX, eccentric and combined EMG activity and concentric IEMG activity during SLDL were higher than DL, except for the concentric activity of GMAX. (7)

ROMANIAN AND STIFF LEGGED DEADLIFT

SLD and RD exercises work the hamstring muscles in common, but although they are very similar exercises, there are differences between them. In both exercises, the knees are performed in a squat-like flexion/extension position or a constant angle is maintained throughout the movement. (14) In SLD, the legs are in extension (slight flexion is not a problem) while the bar is lowered directly to the ground. In RD, the bar is lowered to the tibia (shin bone) using the hip joint, with the knees flexed at approximately 15°. Another difference is that in SLD the barbell descends towards the ground, while the RD bar does not fully descend to the ground but remains in close contact with the legs. (9) In the study conducted in 2022, semitendinosus was stimulated more in RD than in SD, and there was no difference between them for biceps femoris. (14) These two exercises still provide high levels of hamstring EMG activation. (9-11-12-13)

The tables above compare various hamstring exercises with the prone leg curl exercise. The black line represents the prone leg curl exercise.

Hex Bar Deadlift

The hex bar was first introduced in the strength and conditioning literature in 1987 by Gentry and others. This first model had a 4-sided diamond shape in the lifting frame. The framework has been adapted over the years and the most common design is now known as the hexagon (i.e. 6 sides). Anthropometric factors such as height, torso, leg and arm length can all affect a person's ability to successfully perform the traditional deadlift. The impact of these limitations formed part of the rationale for the original hex bar design. (10)

Coming to hamstring activation, the hex bar deadlift exercise is a very effective exercise on the hamstring muscles compared to other deadlift variations. (6)

Effect of Squat Exercise on Hamstring Activation

Squat exercise is a very effective lower body exercise that is frequently performed in gyms. It has many variations. Is it as effective on the hamstring muscles as it is on the quadriceps muscles?

While exercises that involve knee flexion are effective for hamstring development, exercises that involve hip and knee extension, such as squats, etc. It is inadequate in terms of hamstring development. (15)

In another study, the volumes of each component of the hamstring muscles in the back squat exercise performed at different depths did not change significantly after training in both groups. (16)

FATİH BURAK KAYA

BEYKOZ UNIVERSITY PHYSIOTHERAPY

FITNESS TRAINER

resources

(1) Greater Hamstrings Muscle Hypertrophy but Similar Damage Protection after Training at Long versus Short Muscle Lengths Sumiaki Maeo,1 Meng Huang,2 Yuhang Wu,2 Hikaru Sakurai,2 Yuki Kusagawa,2 Takashi Sugiyama,3 Hiroaki Kanehisa,2 and Tadao Isaka2

(2) https://www.acefitness.org/continuing-educatio n/certified/february-2018/6896/ace-sponsored-research-what-is-the-best-exercise-for-the-hamstrings/

(3) Effect of Nordic Hamstring Exercise Intervention Volume on Eccentric Force and Muscle Architecture Adaptations: A Systematic Review and Meta-analyses Matthew Cuthbert, Nicholas Ripley, John J.McMahon, Martin Evans ,G. Gregory Haff &Paul Comfort

(4) Comparison of Muscle Involvement and Posture Between the Conventional Deadlift and a “Walk-In” Style Deadlift Machine Snyder, Benjamin J.; Cauthen, Courtney P.; Senger, Scott R.

(5) An electromyographic analysis of sumo and conventional style deadlifts. Escamilla RF1, Francisco AC, Kayes AV, Speer KP, Moorman CT 3rd

(6) Electromyographic Comparison of Barbell Deadlift, Hex Bar Deadlift, and Hip Thrust Exercises: A Cross-Over Study Andersen, Vidar1; Fimland, Marius S.2; Mo, Dag-Andrè1; Iversen, Vegard M.2; Vederhus, Torbjørn1; Rockland Hellebø, Lars R.1; Nordaune, Kristina I.1; Saeterbakken, Atle H.1

(7) Comparison of EMG Activity between Single-Leg Deadlift and Conventional Bilateral Deadlift in Trained Amateur Athletes - An Empirical Analysis WIKTOR DIAMANT,1, STEPHAN GEISLER,2, TIM HAVERS,2,† and AXEL KNICKER1,

(8) THE IMPLICATIONS OF UNILATERAL TRAINING ON PERFORMANCE TP Wyland GF "Cisco" Reyes

(9) An electromyographic and kinetic comparison of conventional and Romanian deadlifts Author links open overlay panel, Sangwoo Lee, Jacob Schultz, Joseph Timgren, Katelyn Staelgraeve, Michael Miller, Yuanlong Liu

(10) Exercise Technique: Applying the Hexagonal Bar to Strength and Power Training Lockie, Robert G. PhD1; Lazar, Adrian BSc2

(11) Electromyographic activity in deadlift exercise and its variants. A systematic review Isabel Martín-Fuentes, Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Writing – original draft, Writing – review & editing, #1 José M. Oliva-Lozano, Conceptualization, Data curation, Methodology, Writing – review & editing, #1 and José M. Muyor, Conceptualization, Data curation, Formal analysis, Funding acquisition, Methodology, Supervision, Writing – review & editing#1,2

(12) Muscle Activation During Various Hamstring Exercises McAllister, Matt J.; Hammond, Kelley G.; Schilling, Brian K.; Ferreria, Lucas C.; Reed, Jacob P.; Weiss, Lawrence W.

(13) Kettlebell swing targets semitendinosus and supine leg curl targets biceps femoris: an EMG study with rehabilitation implications Mette Kreutzfeldt Zebis1,2, Jørgen Skotte3, Christoffer H Andersen3, Peter Mortensen3, Højland H Petersen4, Tine C Viskær4, Tanja L Jensen4, Jesper Bencke2, Lars L Andersen3

(14) An Electromyographic Analysis of Romanian, Step-Romanian, and Stiff-Leg Deadlift: Implication for Resistance Training by Giuseppe Coratella 1,* ORCID,Gianpaolo Tornatore 1ORCID,Stefano Longo 1ORCID,Fabio Esposito 1,2ORCID andEmiliano Cè 1,2ORCID

(15) Hamstring Activation During Lower Body Resistance Training Exercises in International Journal of Sports Physiology and Performance William P. Ebben

(16) Effects of squat training with different depths on lower limb muscle volumes Keitaro Kubo, Toshihiro Ikebukuro & Hideaki Yata