Biomechanical Analysis of “Free (Aerial) Forward Walkover, Landing on One Foot”

Research purpose

Why a biomechanical analysis? According to Gagea (1994: 6), “apart from efficiency, there are

other reasons that may justify the interest in the study of biomechanics. One of these is the need to

expand the biomechanics-related knowledge, and the other one is to increase exercise capacity and

performance in competitions”.

In artistic gymnastics in general, and especially for balance beam apparatus, the learning of any

technical element is carried out based on a biomechanical model that includes the integration of multi-

and cross-disciplinary information from several areas of knowledge and involves completing the

following steps:

•decomposition of movement into component phases; •identification of key-joints and joint movements; •determination of agonist and antagonist muscle groups involved in the specific action in each phase; •identification of specific technical elements addressed (balance, muscle strength or power,

mobility).

The importanceof biomechanical analysis is given by the high performance level that requires the

use of modern training technology in order to capture multiple angles of movement, with all its

kinematics and dynamics, which will double the coach’s “eye” and provide feedback to learning. So,

the current technical level has reached its upper limit, imposing biomechanical analysis in learning.

Research hypothesis

Biomechanical analysis of qualitative research, in parallel with the use of video recording, will

promote the removal of technical mistakes and will lead the gymnast to achieve the model execution.

Subjects

“Take into the consideration that training is performed in an individualized manner”(Teodorescu,

2009: 21). This study is based on a comparative biomechanical analysis between one gymnast who

represents the model execution and six gymnasts who have just learned the studied element on balance

beam (Forward Danilova). Of the six gymnasts, we chose to present the biomechanical analysis for

Z.S., the most representative gymnast, with the best performance.

Description of “Free (aerial) walkover forward,landing on one foot” (Forward Danilova)

“Forward Danilova” is a dynamic acrobatic element classified into salto group, which is found in

most integral exercises to the balance beam and/or floor exercise and can be presented in many forms.

According to gymnast’s skills, the coach can choose the basic variant (the one shown by us) with

landing on one foot, or landing on both feet. In the (2008), the element has the D value,

which means a bonus of 0.40 tenths, or can be combined with other elements and earn a bigger bonus.

Biomechanically, mastery and regulation during the exercise can be made respecting the principle of

the permanent projection of the centre of gravity on the narrow support area of the balance beam.

Rational training for this apparatus requires learning the correct technique since the beginning and

educating the sense of balance using visual analyser and kinaesthetic sensations (Şlemin, 1976: 86).

Biomechanical analysis of model execution and the best gymnast’s execution in the two tests

•Analysis of the preparatory phase

“Step forward must be blocked in order to have a fixed foothold, and lunge will be to achieve the

maximum load and necessary momentum for the next phase. Length of contact with the beam varies

from 0.05 to 0.8 sec., while the centre of gravity moves forward relative to the fulcrum, according to

the model gymnast” (Stroescu, 2014) (Figure 1 (left)).

At the initial testing in the preparatory phase, the best gymnast, Z.S., presents a coxofemoral joint

angle smaller than in the model gymnast, the scapular-humeral joint angle is large, the preparation step

is short, which leads to weaker momentum (Figure 1 (middle)). In the final testing, the trunk remains bent in the

preparatory phase, but other indicators approach to the model values (Figure 1 (right)).

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•Analysis of routing - Loading phase

“This phase is that in which there is continuous lowering and arm lowering, torso forward and

down, while balancing in speed the oscillating rear leg. Since angular momentum is the product of the

moment of inertia and angular velocity (Donskoi, 1959: 56), the gymnast can increase angular velocity

when the oscillating body and leg reach the peak and achieve this tense “arc”, which will trigger

vertical momentum and detachment (Stroescu, 2014) (Figure 2 (left)).

In this initial testing phase, the gymnast presents low mobility in the sacroiliac joint and incorrect

head positioning (chin to chest) (Figure 2 (middle)). In the final testing, all values of joint angles are improved

(Figure 2 (right)).

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•Analysis of detachment - Elevation

“This impetus triggered by the past actions of forces engaged is the culmination of achieving

vertical phase separation. Detachment effort is made by the triple chain leg extension. Contraction of

the muscle groups for overcoming mechanical work must coincide in time, contrary to the thigh and

lower leg lever formats which constitute a deterrent (Figure 3 (left)). Due to the small step of preparation,

elevation is not sufficient, and that compensatory movement appears as a bent-leg landing” (Stroescu,

2014) (Figure 3 (middle)). The final testing of biomechanical indicators is close to the model values, except that

further head positioning is poor (Figure 3 (right)).

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•Analysis of flight - Rotation

“Movement biomechanics is always coordinated, which implies restrictions in trajectory, speed time

and sometimes accelerations. While rotation occurs, swing foot landing prepares thus to form another

tense “arc”, which will help to further raise the trunk that, this time, remains in extension. Iliac and

abdominal muscles play an important role in this movement phase, as they provide the physical support

required to maintain the final position (Figure 4 (left)).

During the flight phase, in the initial testing, the coxofemoral joint angle is too small, the gymnast

bringing the trunk towards the foot in place of the spine extension, and the leg which has triggered the

separation is not controlled (Figure 4 (middle)). In the final testing, biomechanical indicator values are close to

the model” (Stroescu, 2014) (Figure 4 (right)).

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•Analysis of landing phase

According to the previous phase, the foot is ready for landing, and this is achieved by successive

contacts of foot with cushions, while raising the trunk until it reaches the standing away position in the

sagittal plane. Beam contact is gradually made with metatarsals, leaving the entire sole weight (Figure 5 (left)). “These movements engage in effort the entire body, especially bone-ligament and muscle

systems” (Grigore, 1998: 43).

“As regards landing in the initial testing (Figure 5 (middle)), wrong arm positioning (too close to the trunk)

and lack of extension in the spine lead to a landing with major mistakes (additional movements of

arms, incorrect positioning of feet and additional step for balancing). In the final testing, landing is

done properly, without penalty” (Stroescu, 2014) (Figure 5 (right)).

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