TECHNIQUE ANALYSIS OF THE BACK TOSS ON THE PARALLEL BARS PERFORMED BY ELITE GYMNASTS

The back toss (BT), a skill frequently performed by gymnasts on the parallel bars (PB), involves a release-regrasp swing type of motion from a handstand to a handstand position. Mastering the skill is beneficial not only for points awarded to gymnasts by the judges for the skill itself but also for its contribution towards the perfect execution of other PB skills including the most current1 PB dismounts. The purpose of this study was to: I) identify the skill variables best correlating with the scores given to the BTs by qualifying judges, and 2) to identify the differences in technique between the most and least skillful BTs. Seventeen BTs, recorded during the 1990 United States Gymnastics Federation Championships with a NAC 400 HSV camera operating at 200 Hz, were analyzed utilizing the Arid Performance Analysis System (APAS). Two dimensional position data of 4 (for BTs without knee or elbow joint flexion) to 6 (BTs with elbow and/or knee joint flexion) body points were digitally smoothed before being submitted to further analysis. Product moment correlations between mechanical variables and the scores given to the BTs by qualifying judges, indicate that the best predictors of a good score are the shoulder joint angle at regrasp (p = .001), the time the gymnasts were airborne (p = .021), the horizontal velocity of the center of gravity (COG) at release (p = .022), the hip joint angle at release (p = .025), the hip joint angle at release and the minimum hip joint angle (p = .025 and .048, respectively), the normalized maximum height of the COG above the bar (p =.028), the greatest total angular momentum (p = .035), and the shoulder joint angle at release (p = .054). Paired t tests between variables of the most (N=8) and least (N=9) skillful BTs indicate that the discriminating factors are the hip joint angle at release (p = .03), the shoulder joint angle at regrasp (p = .032), time from the smallest hip joint angle to zero degrees of anterior shoulder joint angle (p = .049), and the horizontal velocity of the COG at release (p = .058). Additional factors differentiating the best and worst BTs studied are the time from zero degrees of anterior shoulder joint angle to release (p = .06), and the shoulder joint angle at release (p = .066

KINEMATICS OF GIANT SWINGS ON THE PARALLEL BARS

The purpose of this study was to investigate the kinematics of giant swings on the parallel bars. A secondary purpose was to compare giants executed from a cast to the giants following, and to compare skilled vs. unskilled performances. A total of eight giants were studied. Results showed that, with few exceptions, giant swings performed on the parallel bars exhibit similar motion patterns to giants performed on other apparatuses. Between-apparatus differences in motion patterns at the knee (quantified), elbow and radioulnar (not quantified due to substantial out-at-plane components) joints were attributed to limitations mostly imposed by apparatus design. Skilled vs. unskilled differences-most pronounced at the shoulder joint-were related to both timing and ROM issues

TEMPORAL CHARACTERISTICS OF THOMAS FLAIRS ON THE POMMEL AND FLOOR

To perform successfully on any apparatus, gymnasts must execute skills with creativity and virtuosity. Whereas creativity is demonstrated by introducing new skills, combining existing ones, or adapting skills to different apparatuses, virtuosity is expressed by executing skills with exceptional technique (Prassas et al. 2006). The Thomas Flairs (Fig. 1), originally introduced and performed on the pommel horse, have been adapted on other apparatuses including the floor. Understanding the timing of the different phases of the skill and what effect the different physical characteristics of the two apparatuses may impose on that timing, would be valuable to coaches and gymnasts seeking to improve performance, judges evaluating gymnastic routines, and scientists studying motor skills

MECHANICAL ANALYSIS OF THE INVERTED GIANT SWING

Strength, balance, flexibility, speed, proper timing, and stamina have long been considered a necessity for the sport of gymnastics. However, the explosive worldwide development of the sport the last decade established another factor --the mastering of swinging --to be of paramount importance for gymnasts desiring to succeed in competition. Among the different kinds of swings, the giant swing refers to those gymnastic skills which require a full 360 degree rotation of the gymnast's suspended body about a relatively fixed point. Depending on the direction of the rotation, the gymnast's body configuration and the type of handgrasp, the degree of difficulty for the various types of the existing giant swings ranges from low to high. With reference to the horizontal bar, the forward and backward giant swings are considered, for example, fundamental but of low difficulty, whereas the so called "inverted" and "German" giant swinqs are given high marks for difficulty

ANALYSIS OF DROP JUMPS WITH AND WITHOUT CONTROL OF CONTACT TIME

The purpose of this study was to compare drop jumping from various heights with and without controlling for contact time. Twenty healthy individuals performed drop jumps from various. Preliminary EMG, power, and kinematic results showed some changes in motion patterns when controlling for contact time. Those patterns, however, did not significantly alter the height jumped

THOMAS FLAIRES ON THE POMMEL AND FLOOR: A CASE STUDY

To win bonus points, gymnasts must execute skills with creativity, virtuosity, and consistency. Creativity is demonstrated by introducing new skills, combining existing ones, or adapting skills that were initially performed in a particular apparatus to other ones. Virtuosity is expressed by executing skills with exceptional technique. The Thomas Flaires (circles performed with the legs split as shown in Figure 1) were originally introduced and performed on the pommel horse, but have since been adapted on other apparatuses including the floor exercises and parallel bars. Understanding the complexity by which consecutive Thomas Flaires are performed and what effect—if any—the different physical characteristics of the two apparatuses may impose on the execution of the skill would be valuable to coaches and gymnasts seeking to improve performance, judges evaluating gymnastics routines, and scientists studying motor skills

SHOULDER JOINT TORQUES AND THE STRAIGHT ARM/FLEXED HIPS PRESS HANDSTAND ON THE PARALLEL BARS

The recent rapid growth of the sport of gymnastics may be based, among other factors, on its versatility. Gymnasts attempt to win points in each of the various events by combining certain skills into spectucular eye pleasing routines. However, while the sport's governing body gives the athlete considerable freedom to choose or develop the appropriate skills for a particular routine, it also imposes certain restrictions. One of those restrictions is that routines on the floor, rings, and parallel bars should include a press handstand, i.e. a gymnastic skill requiring the slow elevation of an individual's body from an initial (usually an "L") stationary position to a handstand position. Several variations of press handstands exist depending on body configuration between initial and final positions. One of them, the straight arms/flexed hips press (SAFHP), is the variation most commonly used by gymnasts, and is depicted in Figure 3 (see results)

ELECTROMYOGRAPHIC (EMG) ACTIVITY OF LOWER EXTREMITY MUSCULATURE DURING DROP JUMPING FROM DIFFERENT HEIGHTS

The purpose of this study was to determine EMG activation patterns of the lower extremity musculature during drop jumping from different heights. Ten subjects participated in the study. EMG activity of the rectus femoris, biceps femoris, and gastrocnemious muscles as well as ground reaction forces were simultaneously recorded during drop jumping from 20, 30, and 40cm. Sagittal video data were also recorded and synchronized to the analog data. Results show similar jump height and EMG activation patterns for the 20 and 40cm drop jumps, but not for the 60cm. It was concluded that activation patterns of the lower extremity musculature varies when the drop height exceeds certain limits. The activation pattern of gastrocnemious deviated from the one described in the literatur

CHANGES OF FORCE AND SPEED CHARACTERISTICS IN MALES AND FEMALES EIGHT TO FIFTY YEARS OLD

The purpose of this study was to determine changes of force and speed characteristics in male and female subjects from eight to 50 years old. Four hundred and eighteen sedentary subjects grouped by age from eight to 50 years old were tested for several force and speed indicators. One-way ANOVA revealed that the majority (four out of six) of force and speed characteristics showed significant increases in subjects up to 30 years of age and subsequent significant decreases. The remaining two indicators showed continuous decline throughout the tested lifespan. It is suggested that these results may be used as a criterion which may assist in promoting physical activity and sport beyond the age of 30 years

Questioning Classic Patient Classification Techniques in Gait Rehabilitation: Insights from Wearable Haptic Technology

Classifying stroke survivors based on their walking abilities is an important part of the gait rehabilitation process. It can act as powerful indicator of function and prognosis in both the early days after a stroke and long after a survivor receives rehabilitation. This classification often relies solely on walking speed; a quick and easy measure, with only a stopwatch needed. However, walking speed may not be the most accurate way of judging individual’s walking ability. Advances in technology mean we are now in a position where ubiquitous and wearable technologies can be used to elicit much richer measures to characterise gait. In this paper we present a case study from one of our studies, where within a homogenous group of stroke survivors (based on walking speed classification) important differences in individual results and the way they responded to rhythmic haptic cueing were identified during the piloting of a novel gait rehabilitation technique