Comparison of muscle activation and kinematics during free-weight back squats with different loads.

08:00 EDT 16th May 2019 | BioPortfolio

Summary of "Comparison of muscle activation and kinematics during free-weight back squats with different loads."

Although several studies have examined the effects of performing resistance training with different percentages of one-repetition maximum (1-RM), little is known of the neuromuscular effects and kinematics of lifting low to heavy loads with maximal movement velocity. The aim of this study is to compare muscle activation and kinematics in free-weight back squats with different loads. Thirteen resistance-training males (aged 24.2 ± 2.0 years, body mass 81.5 ± 9.1 kg, height 1.78 ± 0.06 m) with 6 ± 3 years of resistance-training experience conducted squats with 30%-100% of 1-RM. Barbell kinematics and electromyographic (EMG) activity of the vastus lateralis, vastus medialis, rectus femoris, semitendinosus, biceps femoris, and gluteus maximus were measured in the upward phase of each load. With increasing loads, the barbell velocity decreased, the upward phase duration increased, and the peak velocity occurred later. The muscle activation in all muscles increased with increasing loads but was not linear. In general, similar muscle activation in the prime movers was observed for loads between 40% and 60% of 1-RM and between 70% and 90% of 1-RM, with 100% of 1-RM being superior to the other loads when the loads were lifted at maximal intended velocity. However, the timing of maximal muscle activations was not affected by the different loadings for the quadriceps, but the timing was sequential and independent of loading (rectus femoris before vastus medial before vastus lateral). Maximal activation in the gluteus and semitendinosus increased with increasing loads. This means that for muscle activation, maximal lifting velocity may compensate for increased loads, which may allow resistance-trained athletes and individuals in rehabilitation to avoid heavy loads but still get the same muscle activation.


Journal Details

This article was published in the following journal.

Name: PloS one
ISSN: 1932-6203
Pages: e0217044


DeepDyve research library

PubMed Articles [20172 Associated PubMed Articles listed on BioPortfolio]

Age- and low back pain-related differences in trunk muscle activation during one-legged stance balance task.

Postural control declines with age and can be affected by low back pain. Poor balance has been reported in people with chronic low back pain (CLBP), which in turn could be explained by the changes in ...

Age-related changes in trunk muscle activity and spinal and lower limb kinematics during gait.

The influence of age on spinal muscle activation patterns and its relation to kinematics is poorly understood. We aimed at understanding age-related changes to spine and trunk muscle activity in addit...

Variable, but not free-weight, resistance back squat exercise potentiates jump performance following a comprehensive task-specific warm-up.

Studies examining acute, high-speed movement performance enhancement following intense muscular contractions (frequently called 'post-activation potentiation'; PAP) often impose a limited warm-up, com...

Effects of tactile feedback on lumbar multifidus muscle activity in asymptomatic healthy adults and patients with low back pain.

Reduced lumbar multifidus (LM) muscle contraction has been observed in patients with low back pain (LBP). Clinicians often use various strategies to ensure LM activation, including tactile feedback an...

Lumbar axial rotation kinematics in men with non-specific chronic low back pain.

Lumbar flexion, coupled with rotation, is a dominant factor in the etiology and exacerbation of low back pain. Yet, no study has examined its kinematics in patients with non-specific chronic low back ...

Clinical Trials [14262 Associated Clinical Trials listed on BioPortfolio]

Spinal Kinematics Variability

This study will test the within and between day variability of spinal kinematics and trunk muscle activity in healthy subjects and chronic low back pain patients during various daily-life ...

Shoulder Brace on Muscle Activation and Scapular Kinematics in Patients With Shoulder Impingement Syndrome and Rounded Shoulder Posture

Background: Rounded shoulder posture (RSP), associated with altered scapular kinematics and imbalance of muscle activation, is one of potential risks for shoulder impingement syndrome (SI...

Physiotherapy Re-education of Pre-activation of the Transverse Abdominis in Patients With Chronic Low Back Pain

Hypothesis: The hypothesis of the study is that the physiotherapeutic re-education of the pre-activation of the transverse abdominal muscle decreases pain intensity in patients with chroni...

Spinal Kinematics in Chronic Low Back Pain

Chronic low back pain (CLBP) is one of the most frequent causes for limitations in daily, leisure and work-related activities. Although alterations in spinal motor behavior were consistent...

Effects of Unstable Shoes on Trunk Muscle Activity, Lumbar Spine Kinematics and Pain in Patients With Low Back Pain

Aim: To compare trunk muscle activity, lumbar spine range of motion (ROM) and LBP during gait using an unstable shoe (Intervention group) and a conventional stable control shoe (Control Gr...

Medical and Biotech [MESH] Definitions

Comparison of various psychological, sociological, or cultural factors in order to assess the similarities or diversities occurring in two or more different cultures or societies.

Two muscles, the serratus posterior superior and serratus posterior inferior, located in between the deep and the superficial back muscle layers. Their function is to control THORAX movement.

A heterogeneous group of drugs used to produce muscle relaxation, excepting the neuromuscular blocking agents. They have their primary clinical and therapeutic uses in the treatment of muscle spasm and immobility associated with strains, sprains, and injuries of the back and, to a lesser degree, injuries to the neck. They have been used also for the treatment of a variety of clinical conditions that have in common only the presence of skeletal muscle hyperactivity, for example, the muscle spasms that can occur in MULTIPLE SCLEROSIS. (From Smith and Reynard, Textbook of Pharmacology, 1991, p358)

A form of muscle hypertonia associated with upper MOTOR NEURON DISEASE. Resistance to passive stretch of a spastic muscle results in minimal initial resistance (a "free interval") followed by an incremental increase in muscle tone. Tone increases in proportion to the velocity of stretch. Spasticity is usually accompanied by HYPERREFLEXIA and variable degrees of MUSCLE WEAKNESS. (From Adams et al., Principles of Neurology, 6th ed, p54)

Developmental events leading to the formation of adult muscular system, which includes differentiation of the various types of muscle cell precursors, migration of myoblasts, activation of myogenesis and development of muscle anchorage.

Quick Search


DeepDyve research library

Relevant Topic

Arthritis Fibromyalgia Gout Lupus Rheumatic Rheumatology is the medical specialty concerned with the diagnosis and management of disease involving joints, tendons, muscles, ligaments and associated structures (Oxford Medical Diction...

Searches Linking to this Article