At Twist Conditioning we always ensure our curriculum and training style is supported in current day research. Every Month we will be showcasing some of the literature we have come across. This weeks literature review focuses on Static Stretching vs. Dynamic Warm Up pre-training.

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SURFACE ELECTROMYOGRAPHIC ASSESSMENT OF THE EFFECT OF STATIC STRETCHING OF THE GASTROCNEMIUS ON VERTICAL JUMP PERFORMANCE

WALLMANN, H.W, J.A MERCER, J.W MCWHORTER

Stretching should be incorporated into warm-up routines to prepare muscles for physical activity, enhance performance and prevent injuries. Much of the research surrounding stretching has examined the benefits and effects on flexibility, however there is little evidence on its effect on dynamic muscular performance. Previous literature states that there are negative short-term effects on vertical jump performance following static stretching. Vertical jump performance has been shown to decrease with PNF and passive stretching techniques (Nelson et al., 1996; Church et al., 2001).

Purpose: To investigate the effects of static stretching of the gastrocnemius muscle on maximal vertical jump performance through a vertical jump task and EMG measurements.

Methods: Fourteen healthy adults (8 men, 6 women) age 18-34 years participated in the study. Each participant was familiar with the vertical jump task. Each participant performed three baseline maximal vertical jumps following a warm-up, then rested for 15 minutes, prior to three 30-second static stretches on both the left and right gastrocnemius muscles. Following the stretching session the participants then performed three maximal vertical jumps. The vertical jump performance was measured using a vertical height measurement and EMG activity of the left and right gastrocnemius muscle.

Conclusion: Jump height was decreased from the pre-stretching session when compared to the post stretching session by 5.6%, however the muscle activity was 17.9% higher post stretch to pre-stretch. The results indicate that even though muscle activity is increased following a static stretching session; the muscular performance is decreased as seen with a decrease in vertical jump height.

Practical Implications: Coaches and athletes should be aware that vertical jump performance could be negatively affected when static stretching is performed prior to performing their sport

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EFFECTS OF STATIC STRETCHING FOR 30 SECONDS AND DYNAMIC STRETCHING ON LEG EXTENSION POWER

Yamaguchi, T, K. Ishii

Stretching is performed prior to physical activity in order to prevent injuries and enhance sports performance by improving flexibility. There are numerous types of stretching: static, ballistic, proprioceptive neuromuscular facilitation (PNF) and dynamic stretching. Many coaches and athletes adopt static stretching due to it’s ability to be performed safely and quickly. However static and ballistic stretching prior to exercise has been linked to a decrease in muscular performance. Dynamic stretching is said to cause an increase in muscle temperature, and cause post activation potentiation which is a transient improvement of muscular performance, both outcomes resulting in an improved muscular performance.

Purpose: Compare the effects of static stretching for 30 seconds to dynamic stretching on muscular performance

Methods: 11 healthy recreationally active male college students participated in the study (average age 22.8 years). Each participant was pre tested for leg extension power using a leg extension power measurement system (Anaero Press 3500). Participants then performed static stretching, dynamic stretching and non-stretching in a randomized order on separate days measuring leg extension power before and after the stretching session. The stretching session were designed to target each muscle being records. The static stretching session included stretches for all muscles and was held for 30 seconds.

Five muscles in both of the lower limbs were measured using EMG; plantor flexors, hip extensors, hamstrings, hip flexors, and quadriceps femoris in order to compare the pre and post muscle power results. Stretching was performed to isolate and target each of the five muscles for the dynamic and static stretching.

Conclusions: Static stretching when compared to no stretching did not alter the leg extension power pre to post test, however, the leg extension power was increased with dynamic stretching when compared to no stretching or static stretching

Practical Implications: If dynamic stretching is performed prior to physical activity as opposed to static stretching the muscular performance (strength and power) can be increased.