In the sports domain, biomechanics play a very important role. Athletes are constantly looking for ways to improve performance and to have an advantage over an opponent. At the elite level, technique and proper execution is often the deciding factor in a win or loss. However, in some particular cases, having the “proper form” is irrelevant and numerous solutions can bring about successful execution of the desired movements (Schleihauf, 2004). For instance, there could be multiple techniques a quarterback could use to throw a football. Some quarterbacks throw side armed, some overhand. Although a quarterback coach may insist that there are certain mechanics a quarterback should have when throwing the football, there are some that make it without the ideal form. A prime example is Bret Farve; who consistently does things that are not considered to be proper quarterback mechanics. On the other hand, there are some activities where proper mechanics for a movement are essential. In these cases, the range for effective movement solutions is very small. An example of this would be a track start in the 100 meter sprint.
Sprinters have a particular set of movements that they go through before the start of a race. A good or bad start out the blocks can determine the outcome of a race. Additionally, one might argue that competitive running does require a certain amount of technique and running is not purely determined by physiological attributes. To examine this further, a biomechanical analysis was conducted using an experienced runner and a novice runner. The purpose of this experiment was to see if there were significant differences in the runners’ movements that actually impact performance. Running at a high performance level requires skillful and proper timing when all of the body’s joints and extremities move with purpose and function (Saunders, Pyne, Telford, & Hawley, 2004).
This in turn can be viewed as running economy. Running economy (RE) is defined as the energy demand for a given velocity of submaximal running (Saunders, Pyne, Telford, & Hawley, 2004). Research has shown that individuals with better RE will use less energy than an individual with a poor RE. It is hypothesized that the experienced runner will have better RE than the novice performer. From a biomechanical analysis RE can be assessed by several variables. These include oscilation of the body’s centre mass, knee angles during the swing phase, excessive/ non-excessive arm movement, ground reaction forces, and stride length. As stated, the experienced runner should display superiority in the independent variables; thereby reducing the effort needed to maintain the predetermined speeds for jogging and sprinting. II. Results and Discussion
Stride length is an important factor when evaluating the biomechanical analysis for the jog versus sprint movements. Stride length is defined as the distance between points of first contact of the same foot. In relation to the jog versus sprint movement study, the measurements for stride length includes the horizontal distance locations from the right toe during the first support phase and the right toe during the second support phase. Step Length is another factor that comes into play as it measures the distance between the first contact point of one foot and the opposite foot. For normal or symmetrical gait, it is important for step length distances of the right foot and left foot step lengths to be similar measurements. The measurement for step length is related to the stride length measurement. In order to find the stride length value, stride length is step length multiplied by two. In addition to the basic measurements of stride length and step length, these measurements also play an important role in influencing ground reaction forces of the movement as well as joint torque at the hip.
In analyzing the jogging movement, there was a striking difference in stride length between the advanced subject and the beginner subject. As demonstrated in the first figure, the stride length of the beginner subject is shorter than the advanced subject in the jog. The measurements were taken after the right foot is down at the right toe. The stride length for the advanced subject for the jog is noted as 4.21; whereas the stride length for the beginner subject for the jog is 2.42. The differences in stride length comparison could be due to their jogging and running techniques. Another reason for the beginner subject in the jog having a shorter stride length can be due to the influences of their ground reaction forces as well as the subject’s increase in flexing at the hip joint. Figure 1. The beginner subject has a shorter stride length in comparison to the advanced subject in the jog. SHAPE \* MERGEFORMAT Posture at the Right Hip Joint
Posture is another important comparison finding for the biomechanical analysis for the jogging movement for the advanced and beginner subjects. Posture can play an important role of increasing the jogging and sprinting technique of the performer. Also, proper posture can improve running gait in the performer to decrease fatigue and strain on the lower extremities of the body. There is a striking difference between the right hip joint for the two subjects. At the right hip joint, there is an increase in hip flexing for the beginner subject in the jogging movement which is 48.25. In comparison, the advanced subject in the jogging movement has a measurement of 31.38. This is almost a 50% difference in flexing at the hip joint for the beginner subject. Figure 2. The beginner subject has an increase in flexing at the hip joint in comparison to the advanced subject in the jog. SHAPE \* MERGEFORMAT Velocity at the Hip, Knee, and Ankle
Velocities at the hip, knee, and ankle will be compared through linear kinematics in order to quantify the movement at a particular point as well as provide a measurements of the rate of change of the position. The velocity measurement is important in this pilot study analysis because it provides comparison information regarding the jogging movement with the advanced and beginner performers. In the figures below, there velocity curves demonstrate that the advanced subject in the jog has higher velocity at the hip, knee, and ankle in comparison to the beginner subject in the jog. Among the three body points, the velocity at the hip for the advanced subject in the jog has almost 50% increase in velocity at the hip in comparison to the beginner subject.
With the velocities of the knee and ankle, there is about a 5% difference between the advanced and beginner subject. Nevertheless, the advanced subject has an increase in velocity in comparison to the beginner subject. Figure 3. The advanced subject has a greater right hip velocity at 1.12 mps in comparison to the beginner subject’s 0.55 mps right hip velocity for the jogging movement. SHAPE \* MERGEFORMAT Figure 4. The advanced subject has a greater knee velocity at 1.17 mps in comparison to the beginner subject’s 0.96 mps right hip velocity for the jogging movement. SHAPE \* MERGEFORMAT Figure 5. The advanced subject has a greater ankle velocity at 0.93 mps in comparison to the beginner subject’s 0.77 mps right ankle velocity for the jogging movement. SHAPE \* MERGEFORMAT Ground Reaction Force
For the Ground Reaction Force there was a significant difference between the advanced sprint and advanced jogging of 4.3 Newtons. This difference was due to the size of the stride length, for the advanced sprint the right leg was flexed more compared to the right leg of the advanced jog. Although for the beginner sprint and beginner jog there was no significant difference between the two comparisons. This could be due to the technique of the advanced participant and beginner participant, by looking at the diagram their technique looks similar to one another. Figure 6. Advanced subject’s sprint and jogging movement shows a significant difference. SHAPE \* MERGEFORMAT Figure 7. Beginner subject’s sprint and jogging movement does not have a significant difference. SHAPE \* MERGEFORMAT Figure 8. Ground Reaction Force comparisons for the advanced subject and the beginner subject in the jogging movement. SHAPE \* MERGEFORMAT Center of Gravity
A big component of running is vertical oscillation. Previous research has shown that elite runners will exhibit less vertical oscillation than novice runners; this primarily is a result of experienced runners exhibiting more extension at the knee joint during the foot strike, and having longer contact time while producing lower vertical peak force (Saunders, Pyne, Telford, & Hawley, 2004). In this biomechanical analysis, the runners’ center of gravity was used to explore and compare this variable. The center of gravity on the experienced runner was located in the center of the runner’s body; while the center of gravity for the novice runner was slightly in front of the runner. However, the novice runner produced the least amount of vertical oscillation during the jogging phase of the experiment. The peak Py-CG value for the novice runner was 1.02 meters with a minimum value of 0.95 meters for a total change of 0.07 meters. The experienced performer’s peak Py-CG position was also 1.02 meters. However, the experienced runner had a minimum Py-CG value of 0.92 meters resulting in a change of 0.1 meters. Thus, the experienced runner had a greater change in vertical oscillation by 0.03 meters.
When comparing the runners in the sprinting condition the same results were found. The novice runner had lower vertical oscillation than the experienced runner. The peak Py-CG value for the novice performer was 1.03 meters with a minimum value of 0.95 meters. The total difference in position for the novice runner was 0.08 meters. The experienced runner’s peak Py-CG value was 1.05 meters with a minimum value of 0.93 meters. The total oscillation for the experienced runner was 0.12 meters. Moreover, when compared to the novice runner, the experienced runner had a greater amount of vertical oscillation by a margin of 0.04 meters. When the acceleration curves were compared, the experienced runner had both greater positive and negative values for the Ay-CG component. The experienced runner had peak Ay-CG values of 12.68 mps, which occurred at frame 46, and -12.71 mps, which occurred at frame 57.
The novice runner had peak Ay-CG values of 10.19 mps, which occurred at frame 40 and —-9.83 mps, which occurred at frame 54. Figure 9. Center of Gravity comparisons for the experienced and novice subjects for the jogging movement. SHAPE \* MERGEFORMAT However, when the runners were viewed during the sprint condition, the experienced runner had lower peak CG values than the novice runner. In addition, the experienced runner seemed to be more relaxed and exhibited smoother movements. The peak Ay-CG values for the experienced runner during the sprint condition were 16.98 mps and -13.16 mps; the peak Ay-CG values for the novice runner during the sprint condition were 17.47 mps and -15.83 mps.
From these results, one can conclude that CG and vertical oscillation may not be an important variable when jogging, or that vertical oscillation is only important when runners’ are in a true sprinting condition. The results of this study contradict findings from previous studies on vertical oscillation between experienced and novice performers; where the experienced runners’ had the lower vertical oscillation. However, because the runners’ may not have been in a true sprint, results have to be viewed skeptically. In addition, it seems that acceleration values may only be related to the ease at which the performers are running. Joint Torque When evaluating the joint torque differences at the hip between the advanced subject and the beginner subject during the jogging movement, there was a 40% difference. The advanced performer measured at -105.7 and the beginner performer measured at -244.81. This significant difference was due to the stride length, step length distance, posture and body structure of each subject. To calculate torque is to multiply the force times the lever arm. Joint torque relies heavily on the lever arm alone instead of the force because torque is produced more by the length of the lever arm instead of the force of the object.
In the comparison of the sprint versus the jog of the beginner subject and the sprint versus the jog of the advanced subject, the measurements show that the stride length and step length distance for the sprint condition was larger for both subjects. With the stride length and step length being larger, meaning a longer lever arm, it produces a larger torque at the specified joint. The posture played a role as well in the joint torque between the advanced subject and the beginner subject. With the beginner subject showing more hip flexion in comparison of the advanced subject in the jogging condition, it had a direct effect on their technique. This would cause the beginner subject’s stride to be shorter and have limited range of motion while the advanced subject has a practiced technique with better posture producing a longer stride at the hip. Figure 10. In the jogging movement, joint torque at the hip for the beginner performer is 40% greater than the advanced performer.
SHAPE \* MERGEFORMAT III. Suggested Strategies for Future Research This was a small pilot study that can be changed to produce a complete research publication. One may find it beneficial to increase the duration of the experiment. Here one will be able to study possible technique variations that may influence the economy of running by having the subjects reach the point of exhaustion. By comparing kinematic and kinetic changes in the advanced and beginner runner, one may ascertain a theory to the efficiency of different levels of runners based on biomechanics. In addition, one may find it helpful to analyze subjects with the same running background and examine possible differences in biomechanics technique when running on the treadmills flat surface verses the uneven outside pavement. This could be helpful to determine whether training on a treadmill is beneficial to a competitive runner and provide insight as a way to the lower the injury risks caused by the stress of impact of running if it is less on one of the two surfaces.
IV. Conclusions Stride length, vertical oscillation, ground reaction forces, and joint torque are four important kinematic analyses for the advanced versus the beginner during jogging and sprinting movements. From the following data examples, these comparisons provide information regarding important differences between expert and novice performers that may or may not impact performance. The advanced subject showed a longer stride length, resulting in a larger ground reaction force. The novice subject showed a greater joint torque most likely due to the shorter stride length in order to keep up with the same speed.
When comparing the center of gravity point, the novice performer exhibited the lower amount of vertical oscillation in both the jogging and sprinting condition. However, more experiments should be conducted where the runners are truly running at maximum speeds to see if this variable truly has an effect on performance. One was also able to see under the conditions of jogging verses running; only the advanced runner’s kinematic analysis were noticeably different. One can ascertain that this is due to differences in technique and form. Although the data showed that there are biomechanical differences that exist between the experienced and novice performer, these results should be viewed with physiological data to determine whether these differences actually impact running economy.
 Saunders, P., Pyne, D., Telford, R., Hawley, J. (2004). Factors Affecting Running Economy in Trained Distance Runners. Sports Medicine: 34 (7). 465-485.  Schleihauf, R. Biomechanics of Human Movement. AuthorHouse Publishing. 2004.