Warm-Up and Stretching chapter13 Warm-Upand Stretching Ian Jeffreys, MS; CSCS,*D; NSCA-CPT,*D
Warm-Up • Warming up can have the following positive impacts on performance: • Faster muscle contraction and relaxation of both agonist and antagonist muscles • Improvements in the rate of force development and reaction time • Improvements in muscle strength and power • Lowered viscous resistance in muscles • Improved oxygen delivery due to the Bohr effect whereby higher temperatures facilitate oxygen release from hemoglobin and myoglobin • Increased blood flow to active muscles • Enhanced metabolic reactions
Warm-Up • Stretching During Warm-Up • Research suggests dynamic stretching is the preferred option for stretching during warm-up. • Consider the range of motion and stretch-shortening cycle requirements of the sport when designing a warm-up.
Warm-Up • Components of a Warm-Up • A general warm-up period may consist of 5 to 10 minutes of slow activity such as jogging or skipping. • A specific warm-up period incorporates movements similar to the movements of the athlete’s sport. It involves 8 to 12 minutes of dynamic stretching focusing on movements that work through the range of motion required for the sport.
Flexibility • Flexibility is a measure of range of motion (ROM) and has static and dynamic compo-nents. • Static flexibility is the range of possible movement about a joint and its surrounding muscles during a passive movement. • Dynamic flexibility refers to the available ROM during active movements and therefore requires voluntary muscular actions.
Flexibility • Flexibility and Performance • Optimal levels of flexibility exist for each activity. • Injury risk may increase outside this range.
Flexibility • Frequency, Duration, and Intensity of Stretching • Acute effects of stretching on ROM are transient. • For longer-lasting effects, a stretching program is required.
Flexibility • When Should an Athlete Stretch? • Following practice and competition • Postpractice stretching facilitates ROM improvements because of increased muscle temperature. • Stretching should be performed within 5 to 10 minutes after practice. • Postpractice stretching may also decrease muscle soreness although the evidence on this is ambiguous.
Flexibility • When Should an Athlete Stretch? • As a separate session • If increased levels of flexibility are required, additional stretching sessions may be needed. • In this case, stretching should be preceded by a thorough warm-up to allow for the increase in muscle temperature necessary for effective stretching. • This type of session can be especially useful as a recovery session on the day after a competition.
Flexibility • Proprioceptors and Stretching • Stretch reflex • A stretch reflex occurs when muscle spindles are stimulated during a rapid stretching movement. • This should be avoided when stretching, as it will limit motion.
Flexibility • Proprioceptors and Stretching • Autogenic inhibition and reciprocal inhibition • Autogenic inhibition is accomplished via active contraction before a passive stretch of the same muscle. • Reciprocal inhibition is accomplished by contracting the muscle opposing the muscle that is being passively stretched. • Both result from stimulation of Golgi tendon organs, which cause reflexive muscle relaxation.
Types of Stretching • Static Stretch • A static stretch is slow and constant, with the end position held for 30 seconds. • Ballistic Stretch • A ballistic stretch typically involves active muscular effort and uses a bouncing-type movement in which the end position is not held. • Dynamic Stretch • A dynamic stretch is a type of functionally based stretching exercise that uses sport-specific move-ments to prepare the body for activity.
Types of Stretching • Proprioceptive Neuromuscular Facilitation (PNF) Stretch • Hold-Relax • Passive prestretch (10 seconds), isometric hold (6 seconds), passive stretch (30 seconds)
Positions for PNF Hamstring Stretch • Figures 13.1 and 13.2 (next slide) • Starting position of PNF hamstring stretch • Partner and subject leg and hand positions for PNF hamstring stretch
Hold-Relax • Figures 13.3, 13.4, and 13.5 (next slide) • Passive prestretch of hamstrings during hold-relax PNF hamstring stretch • Isometric action during hold-relax PNF hamstring stretch • Increased ROM during passive stretch of hold-relax PNF hamstring stretch
Types of Stretching • Proprioceptive Neuromuscular Facilitation Stretch • Contract-Relax • Passive prestretch (10 seconds), concentric muscle action through full ROM, passive stretch (30 seconds)
Contract-Relax • Figures 13.6, 13.7, and 13.8 (next slide) • Passive prestretch of hamstrings during contract-relax PNF stretch • Concentric action of hip extensors during contract-relax PNF stretch • Increased ROM during passive stretch of contract-relax PNF stretch
Types of Stretching • Proprioceptive Neuromuscular Facilitation Stretch • Hold-Relax With Agonist Contraction • During third phase (passive stretch), concentric action of the agonist used to increase the stretch force
Hold-Relax With Agonist Contraction • Figures 13.9, 13.10, and 13.11 (next slide) • Passive prestretch during hold-relax with agonist contraction PNF hamstring stretch • Isometric action of hamstrings during hold-relax with agonist contraction PNF hamstring stretch • Concentric contraction of quadriceps during hold-relax with agonist contraction PNF hamstring stretch, creating increased ROM during passive stretch
Key Point • The hold-relax with agonist contraction is the most effective PNF stretching technique due to facilitation via both reciprocal and autogenic inhibition.
Types of Stretching • Guidelines for Static Stretching • Get into a position that facilitates relaxation. • Move to the point in the ROM where you experience a sensation of mild discomfort. If performing partner-assisted PNF stretching, communicate clearly with your partner. • Hold stretches for 30 seconds. • Repeat unilateral stretches on both sides.
Types of Stretching • Precautions for Static Stretching • Decrease stretch intensity if you experience pain, radiating symptoms, or loss of sensation. • Use caution when stretching a hypermobile joint. • Avoid combination movements that involve the spine (e.g., extension and lateral flexion). • Stabilizing muscles should be active to protect other joints and prevent unwanted movements.
Types of Stretching • Guidelines for Dynamic Stretching • Carry out 5 to 10 repetitions for each movement, either in place or over a given distance. • Progressively increase the ROM on each repetition. • Increase the speed of motion on subsequent sets where appropriate. • Contract the muscles as you move through the ROM.
Types of Stretching • Precautions for Dynamic Stretching • Move progressively through the ROM. • Move deliberately but without bouncing (movement must be controlled at all times). • Do not forsake good technique for additional ROM.
Resistance Training and Spotting Techniques chapter14 Resistance Trainingand SpottingTechniques Roger W. Earle, MA; CSCS,*D; NSCA-CPT,*DThomas R. Baechle, EdD; CSCS,*D; NSCA-CPT,*D
Figure 14.1 • Figure 14.1 • (a) Pronated • (b) Supinated • (c) Alternated • (d) Hook (posterior view) • closed grip: thumb is wrapped around the bar • Open grip: thumb does not wrap around the bar
Figure 14.2 Grip Widths
Exercise Technique Fundamentals • Stable Body and Limb Positioning • A stable position enables the athlete to maintain proper body alignment during an exercise, which in turn places an appropriate stress on muscles and joints. • Both free-weight and machine exercises require a stable position. The five-point body contact position provides stability for seated or supine exercises. (continued)
Exercise Technique Fundamentals • Stable Body and Limb Positioning (continued) • Following is the five-point body contact position: • Head is placed firmly on the bench or back pad. • Shoulders and upper back are placed firmly and evenly on the bench or back pad. • Buttocks are placed evenly on the bench or seat. • Right foot is flat on the floor. • Left foot is flat on the floor.
Key Point • Exercises performed while standing typically require that the feet be positioned slightly wider than hip-width with the heels and balls of the feet in contact with the floor. Seated or supine exercises performed on a bench usually require a five-point body contact position.
Key Point • Before performing machine exercises, adjust seat and pads to position the body joint primarily involved in the exercise in alignment with the machine’s axis of rotation.
Exercise Technique Fundamentals • Range of Motion and Speed • A full range of motion maximizes the value of an exercise and improves flexibility. • Slow, controlled movements make it easier to achieve a complete ROM, though quick movements are appropriate for power exercises.
Exercise Technique Fundamentals • Breathing Considerations • The sticking point is the most strenuous movement of a repetition, and it occurs soon after the transition from the eccentric phase to the concentric phase. • Instruct athletes to exhale through the sticking point and to inhale during the less stressful phase of the repetition.
Exercise Technique Fundamentals • Breathing Considerations • Valsalva maneuver • For experienced and well-resistance-trained athletes performing structural exercises • Will assist in maintaining proper vertebral alignment and support • Involves expiring against a closed glottis, which, when combined with contracting the abdomen and rib cage muscles, creates rigid compartments of fluid in the lower torso and air in the upper torso • Helps to establish the “flat-back” and erect upper torso position in many exercises
Key Point • For most exercises, exhale through the sticking point of the concentric phase and inhale during the eccentric phase. Experi-enced and well-trained athletes may want to use the Valsalva maneuver when performing structural exercises to assist in maintaining proper vertebral alignment and support.
Exercise Technique Fundamentals • Weight Belts • Typically an athlete should wear a weight belt when performing exercises that place stress on the lower back and during sets that involve near-maximal or maximal loads. • A weight belt is not needed for exercises that do not stress the lower back or for those that do stress the lower back but involve light loads.
Exercise Technique Fundamentals • Lifting a Bar off the Floor • The position of the feet and back shown in figure 14.3 enables the leg muscles to make a major contribution as the bar is lifted off the floor. • Keeping the bar close to the body and the back flat during the upward pull helps avoid excessive strain on the lower back.
Spotting Free Weight Exercises • Types of Exercises Performed and Equipment Involved • With the exception of power exercises, free weight exercises performed with a bar moving over the head, positioned on the back, racked on the front of the shoulders, or passing over the face typically require one or more spotters.
Spotting Free Weight Exercises • Types of Exercises Performed and Equipment Involved • Spotting Overhead Exercises and Those With the Bar on the Back or Front Shoulders • Ideally, to promote the safety of the lifter, the spotters, and others nearby, overhead exercises and those involving the bar on the back or front shoulders should be performed inside a power rack with the crossbars in place at an appropriate height. (continued)
Spotting Free Weight Exercises • Types of Exercises Performed and Equipment Involved • Spotting Overhead Exercises and Those With the Bar on the Back or Front Shoulders (continued) • Out-of-the-rack exercises (e.g., forward step lunge orstep-up) with heavy weights can result in serious injury. • These exercises should be executed only by well-trained and skilled athletes and spotted by experienced profes-sionals.
Spotting Free Weight Exercises • Types of Exercises Performed and Equipment Involved • Spotting Over-the-Face Exercises • When spotting over-the-face barbell exercises, it is important for the spotter to grasp the bar with an alternated grip, usually narrower than the athlete’s grip. Because of the bar’s curved trajectory in some exercises (e.g., lying triceps extension, barbell pullover), the spotter will use an alternated grip to pick up the bar and return it to the floor but a supinated grip to spot the bar.
Spotting Dumbbell Exercises • Figure 14.4 (next slide) • (a) Incorrect dumbbell spotting location • (b) Correct spotting location • Arrows indicate the spotter’s hand placement on the athlete’s arms.
Spotting Free Weight Exercises • Types of Exercises Performed and Equipment Involved • Do Not Spot Power Exercises