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All conclusions of studies will be listed in this original post (TABLE OF SUMMARIES) for quick reference.


Post any study related to sprint performance (less than or equal to 100m). This could be anything from muscle groups, energy systems, limb leverages, strength, etc.

1. Breakdown of high-energy phosphate compounds and lactate accumulation during short supramaximal exercise

We concluded that 1) in short-term maximal exercise, performance depends on the capacity for using high-energy phosphates at the beginning of the exercise, and 2) the decrease in running speed begins when the high-energy phosphate stores are depleted and most of the energy must then be produced by glycolysis.

2. Neural Influences on Sprint Running: Training Adaptations and Acute Responses.

Nerve conduction velocity (NCV) has been shown to increase in response to a period of sprint training.

An increase in motoneuron excitability, as measured by the Hoffman reflex (H-reflex), has been reported to produce a more powerful muscular contraction,

 In contrast, stretch reflexes appear to be enhanced in sprint athletes possibly because of increased muscle spindle sensitivity as a result of sprint training.

Fatigue of neural origin both during and following sprint exercise has implications with respect to optimising training frequency and volume.

3. Leg power and hopping stiffness: relationship with sprint running performance.

Although muscle power is needed for acceleration and maintaining a maximal velocity in sprint performance, high leg stiffness may be needed for high running speed. The ability to produce a stiff rebound during the maximal running velocity could be explored by measuring the stiffness of a rebound during a vertical jump.

4. Stepping Backward Can Improve Sprint Performance Over Short Distances.

The results from this investigation question the advocacy of removing the false step to improve an athlete's sprint performance over short distances. In fact, if the distance to be traveled is as little as 0.5 m in the forward direction, adopting a starting technique in which a step backward is employed may result in superior performance.

5. Starting from standing; why step backwards?

The results indicate a positive contribution to the force and power from a step backwards. We advocate developing a training program with special attention to the phenomenon step backwards.

6. Influence of high-resistance and high-velocity training on sprint performance.

The HV (HIGH VELOCITY) group improved significantly in total 100 m time (P < 0.05 compared with the RUN and PAS groups (CONTROL GROUPS)). The HR (HIGH RESISTANCE) program resulted in an improved initial acceleration phase (P < 0.05 compared with PAS).

7. The optimal downhill slope for acute overspeed running. (2008)

Compared with the 4.7 degrees slope, the 5.8 degrees slope yielded a 0.10-s faster 40-yd sprint time, resulting in a 1.9% increase in speed. CONCLUSIONS: Those who train athletes for speed should use or develop overspeed hills with slopes of approximately 5.8 degrees to maximize acute sprinting speed. The results of this study bring into question previous recommendations to use hills of 3 degrees downhill slope for this form of overspeed training.

8. Effect of Elastic-Cord Towing on the Kinematics of the Acceleration Phase of Sprinting

Elastic-cord tow training resulted in significant acute changes in sprint kinematics in the acceleration phase of an MS that do not appear to be sprint specific.

9. The Effectiveness of an 8-week High Speed Treadmill Training Program on High School Athletes.

10. Leg strength and stiffness as ability factors in 100 m sprint running.

The concentric half-squats were related to 100 m (r=0.74, p<0.001) and to the mean speed of each phase (R=0.75, p<0.01). The counter movement jump was related to 100 m (r=0.57, p<0.05) and was the predictor of the first phase (r=0.66, p<0.01). The hopping test was the predictor of the two last phases (R=0.66, p<0.05). Athletes who had the greatest leg stiffness (G1) produced the highest acceleration between the first and the second phases, and presented a deceleration between the second and the third ones. CONCLUSIONS: The concentric half-squats test was the best predictor in the 100 m sprint. Leg stiffness plays a major role in the second phase.

11. Influence of strength training on sprint performance. Current findings and implications for training.

Immediately following the start action, the powerful extensions of the hip, knee and ankle joints are the main accelerators of body mass. However, the hamstrings, the m. adductor magnus and the m. gluteus maximus are considered to make the most important contribution in producing the highest levels of speed.

12. The effects of sprint running training on sloping surfaces.

Maximum running speed and step rate were increased significantly (p < 0.05) in a 35-m running test after training by 0.29 m.s(-1) (3.5%) and 0.14 Hz (3.4%) for the combined uphill-downhill group and by 0.09 m.s(-1) (1.1%) and 0.03 Hz (2.4%) for the downhill group, whereas flight time shortened only for the combined uphill-downhill training group by 6 milliseconds (4.3%)...It can be suggested that the novel combined uphill-downhill training method is significantly more effective in improving the maximum running velocity at 35 m and the associated horizontal kinematic characteristics of sprint running than the other training methods are.

13. Relationship between strength qualities and sprinting performance.

Pearson correlation analysis revealed that the single best predictor of starting performance (2.5 m time) was the peak force (relative to bodyweight) generated during a jump from a 120 degree knee angle (concentric contraction) (r = 0.86, p = 0.0001). The single best correlate of maximum sprinting speed was the force applied at 100 ms (relative to bodyweight) from the start of a loaded jumping action (concentric contraction) (r = 0.80, p = 0.0001). SSC measures and maximum absolute strength were more related to maximum sprinting speed than starting ability.

14. Sprint performance is related to muscle fascicle length in male 100-m sprinters.

Muscle thickness was similar between groups for vastus lateralis and gastrocnemius medialis, but S10 had a significantly greater gastrocnemius lateralis muscle thickness. S10 also had a greater muscle thickness in the upper portion of the thigh, which, given similar limb lengths, demonstrates an altered "muscle shape." Pennation angle was always less in S10 than in S11. In all muscles, S10 had significantly greater fascicle length than did S11, which significantly correlated with 100-m best performance (r values from -0.40 to -0.57). It is concluded that longer fascicle length is associated with greater sprinting performance.

Leg power and hopping stiffness: relationship with sprint running performance.

 Abstract:
CHELLY, S. M., and C. DENIS. Leg power and hopping stiffness: relationship with sprint running performance. Med. Sci. Sports Exerc., Vol. 33, No. 2, 2001, pp. 326-333.

Purpose: Although sprint performance undoubtedly involves muscle power, the stiffness of the leg also determines sprint performance while running at maximal velocity. Results that include both of these characteristics have not been directly obtained in previous studies on human runners. We have therefore studied the link between leg power, leg stiffness, and sprint performance.

Methods: The acceleration and maximal running velocity developed by 11 subjects (age 16 +/- 1) during a 40-m sprint were measured by radar. Their leg muscle volumes were estimated anthropometrically. Leg power was measured by an ergometric treadmill test and by a hopping test. Each subject executed a maximal sprint acceleration on the treadmill equipped with force and speed transducers, from which forward power was calculated. A hopping jump test was executed at 2 Hz on a force platform. Leg stiffness was calculated using the flight and contact times of the hopping test.

Results: The treadmill forward leg power was correlated with both the initial acceleration (r = 0.80, P < 0.01) and the maximal running velocity (r = 0.73, P < 0.05) during track sprinting. The leg stiffness calculated from hopping was significantly correlated with the maximal velocity but not with acceleration.

Conclusion: Although muscle power is needed for acceleration and maintaining a maximal velocity in sprint performance, high leg stiffness may be needed for high running speed. The ability to produce a stiff rebound during the maximal running velocity could be explored by measuring the stiffness of a rebound during a vertical jump.






Stepping Backward Can Improve Sprint Performance Over Short Distances.

Original Research
Journal of Strength & Conditioning Research. 22(3):918-922, May 2008.
Frost, David M 1; Cronin, John B 1,2; Levin, Gregory 1

Abstract:
The use of a backward (false) step to initiate forward movement has been regarded as an inferior starting technique and detrimental to sprinting performance over short distances as it requires additional time to be completed, but little evidence exists to support or refute this claim. Therefore, we recruited 27 men to examine the temporal differences among three standing starts that employed either a step forward (F) or a step backward (B) to initiate movement. An audio cue was used to mark the commencement of each start and to activate the subsequent timing gates. Three trials of each starting style were performed, and movement (0 m), 2.5 m, and 5 m times were recorded. Despite similar performances to the first timing gate (0.80 and 0.81s for F and B, respectively), utilizing a step forward to initiate movement resulted in significantly slower sprint times to both 2.5 and 5 m (6.4% and 5.3%, respectively). Furthermore, when the movement times were removed and performances were compared between gates 1 and 2, and 2 and 3, all significant differences were seen before reaching a distance of only 2.5 m. The results from this investigation question the advocacy of removing the false step to improve an athlete's sprint performance over short distances. In fact, if the distance to be traveled is as little as 0.5 m in the forward direction, adopting a starting technique in which a step backward is employed may result in superior performance.






Starting from standing; why step backwards?
Journal of Biomechanics, Volume 34, Issue 2, Pages 211-215
G.Kraan

At push-off, the mass centre of gravity of the body must be positioned in front of the foot to prevent a somersault. When starting a sprint from out the standing position the use of a step backwards is necessary for maximal acceleration. The aim of the present study was to quantify the positive contribution to push off from a backward step of the leg, which seems to be counterproductive. Ten subjects were instructed to sprint start in three different ways: (a) starting from the standing position just in front of the force platform on the subject's own initiative, (b) starting from the standing position on the force platform with no step backward allowed, and (c) starting out of the starting position with one leg in front of the force platform and the push-off leg on the force platform. A step backwards was observed in 95% of the starts from the standing position. The push-off force was highest in starting type (a), which had the shortest time to build up the push-off force. The results indicate a positive contribution to the force and power from a step backwards. We advocate developing a training program with special attention to the phenomenon step backwards.





Influence of high-resistance and high-velocity training on sprint performance.

Medicine & Science in Sports & Exercise. 27(:1203-1209, August 1995.
DELECLUSE, CHRISTOPHE; COPPENOLLE, HERMAN VAN; WILLEMS, EUSTACHE; LEEMPUTTE, MARK VAN; DIELS, RUDI; GORIS, MARINA

Abstract:
The purpose of this study is to analyze the effect of high-resistance (HR) and high-velocity (HV) training on the different phases of 100-m sprint performance. Two training groups (HR and HV) were compared with two control groups (RUN and PAS). The HR (N = 22) and HV group (N = 21) trained 3 d.wk-1 for 9 wk: two strength training sessions (HR or HV) and one running session. There was a run control group (RUN, N = 12) that also participated in the running sessions (1 d.wk-1) and a passive control group (PAS, N = 11). Running speed over a 100-m sprint was recorded every 2 m. By means of a principal component analysis on all speed variables, three phases were distinguished: initial acceleration (0-10 m), building-up running speed to a maximum (10-36 m), and maintaining maximum speed in the second part of the run (36-100 m). HV training resulted in improved initial acceleration (P < 0.05 compared with RUN, PAS, and HR), a higher maximum speed (P < 0.05 compared with PAS), and a decreased speed endurance (P < 0.05 compared to RUN and PAS). The HV group improved significantly in total 100 m time (P < 0.05 compared with the RUN and PAS groups). The HR program resulted in an improved initial acceleration phase (P < 0.05 compared with PAS).

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9. The Effectiveness of an 8-week High Speed Treadmill Training Program on High School Athletes.

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http://www.athleticsweekly.com/featured/leg-stiffness-sprinting-13173