Sentences with phrase «moment arm»

While the peak moment arm length of the long head was 8.5 mm, and the minimum was 6.1 mm.

The the superior and inferior fibers display the largest peak moment arm lengths, while the middle fibers display the smallest.

This purpose of this section is to provide a summary of the muscle moment arms of the calf muscles in each of the main planes of movement.

There is no change in shoulder external moment arm lengths in the sticking region.

The only permanent factors affecting internal moment arm length are peripheral.

The superior fibers display the largest moment arm length and the middle fibers display the smallest.

This type of posture may lead greater external hip extension moment arm lengths because the hip is further from the barbell.

A short plateau region exists between 60 and 70 degrees where the peak moment arm lies.

This purpose of this section is to provide a summary of the muscle moment arms of the biceps muscle in each of the main planes of movement.

This very likely changes the external moment arm at the hip and probably makes the exercise easier to move a heavier barbell load for the same hip joint moment.

The superior and inferior fibers have greater peak moment arm lengths than the middle fibers.

However, internal moment arm lengths also affect changes in the required muscle force at different joint angles.

In most cases, this is caused by differences in external moment arm lengths.

The minimum moment arm length occurred at -15 degrees of plantarflexion (toes pointing upwards).

Many studies that have reported muscle moment arms for the various hamstrings muscles for knee flexion with changing knee angle (Spoor et al. 1992; Herzog & Read, 1993; Wretenberg et al. 1996; Lu et al. 1996; Buford et al. 1997; Kellis et al. 1999).

Elliot et al. (1989) found no difference in moment arm length of the shoulder between successful and unsuccessful lifts (81, 100, 104 % of 1RM).

This indicates that the triceps muscle activity is very high during the bench press and may increase as the elbow joint angle increases (straighter arm), which is in line with the theoretical implications based on moment arm analysis, described above.

They also have a large knee flexion moment arm, making them a key knee flexor.

The overall average moment arm lengths of the deltoids appear to range between -16.8 mm to 24.6 mm depending on the segment of the deltoids and the range of motion measured (Keuchle et al. 1997).

In contrast, the sternocostal head of the pectoralis major provides one of the largest shoulder adduction moment arms of the upper body musculature.

The gluteus maximus was found to have a smaller moment arm length in 90 degrees of hip flexion than in full hip extension.

Murray et al. (1995) found that the overall moment arm length of the biceps varied between its maximum and minimal by 40 % for men and 52 % for females.

Anatomical studies have observed that the hip internal rotation moment arm of the anterior region of the gluteus medius is greater in hip flexion than in hip extension (Delp et al. 1999).

As is clear from the chart below, the middle deltoid has a large shoulder abduction moment arm length, which makes it a prime mover in this movement.

However, it does seem likely that the anterior deltoid moment arm length increases with shoulder flexion and peaks as the arm approaches or passes parallel.

They noted that this was likely because of the non-significantly greater external lumbosacral moment arm length in the straight bar deadlift compared to the hexagonal bar deadlift (21.0 cm vs. 14.4 cm).

Indeed, the pectoralis major has longer moment arm lengths for shoulder horizontal adduction (also called shoulder horizontal flexion) than any of the other chest muscles, indicating it is the prime mover for this action (Keuchle et al. 1997).

The hamstrings displayed similar moment arm lengths in 90 degrees of hip flexion and full hip extension.

Although the deltoids are thought of as abductors, this is only true for the middle deltoid, while the anterior deltoid is a shoulder flexor in the sagittal plane, and the posterior deltoid acts as a shoulder adductor (it has a negative moment arm in abduction) and an antagonist to the middle deltoid (Favre et al. 2009).

Ackland et al. (2008) showed that the inferior sternocostal fibers produce large moment arms throughout full shoulder flexion range of motion that is highest around the mid-range but remains high at 120 degrees (arms above head).

As above, Maganaris et al. (1998) assessed the Achilles tendon moment arm length during rest and maximal voluntary isometric contractions (MVIC).

There seems to be complementary supinator moment arms between the short and long head of the biceps insofar as they produce forearm supination to different extents depending on forearm orientation.

Although different regions of the pectoralis major have different moment arm lengths and behave slightly differently, the following sections provide an overview of the behavior of the overall muscle, in relation to other muscles.

Although Pressel and Lengsfeld (1998), Arnold et al. (2000), and Arnold and Delp (2001) did not provide actual numbers for their studies, they all found that the adductors displayed very small transverse plane moment arms that are probably not meaningful.

The gluteus maximus moment arm for hip extension indicates that it is a key hip extensor in the sagittal plane, and decreases with increasing hip flexion angle.

During successful 1RM attempts the elbow external moment arm reduces in length compared to unsuccessful 1RM attempts.

Therefore, it appears that the biceps moment arm increases from 20 degrees of elbow flexion up to 90 degrees, where it falls again only slightly.

Hip extension moments are the products of the gluteus maximus, hamstrings and adductor magnus muscle forces and their associated moment arm lengths.

However, other factors are also important in identifying the role of the various hip extensors in specific movements, including moment arm lengths.

The negative moment arm implies that the function is to produce shoulder extension (towards the body).

On moment arm alone, it is unclear which muscle is the primary shoulder flexor in the sagittal plane.

Since the upper fibers have a greater abductor moment arm, this seems logical.

Based on the origins and insertions of the muscle, as well as the muscle moment arms derived from cadaver measurements, researchers have generally agreed that the primary role of the gluteus maximus is to perform extension at the hip.

Keuchle et al. (1997) measured the range of motion up to 100 degrees of flexion and did not observe the peak flexor moment arm for the posterior deltoid.

The minimum moment arm length was displayed at -15 degrees of dorsiflexion (toes pointing upwards).

Comparing different squat variations, Swinton et al. (2012) reported that peak ankle moment arm lengths were greater in the traditional squat variation than in either the powerlifting or box squat variations.