Static stretching (SS) is used pervasively throughout the exercise science and sporting communities as a fundamental element of the pre-exercise warm-up procedure.While SS has been proven effective to increase range of motion (ROM), its proposed benefits are questionable and relatively unsubstantiated. Moreover, in recent years researchers have demonstrated that pre-exercise SS may in fact be detrimental to subsequent performance due to impaired force and power output. Yet the practical application of these relatively recent findings is limited due to the prolonged SS protocols utilized. In addition, timelines associated with enhanced ROM and performance decrements have not been established. Thus, the objectives of this study were to determine if a typical SS routine decreased force, activation, and power while improving ROM. Secondly, the study attempted to compare the duration of the performance decrement to the duration of the augmented ROM.ii ACKNOWLEDGEMENTS I believe that the long and arduous process of completing a master's thesis is a great accomplishment made possible in part by the support and guidance of family and friends. I would first like to thank my immediate family. To my parents, Kevin and Jean,

In conclusion, it appears that an acute bout of stretching impaired the warm-up effect achieved under control conditions with balance and reaction/movement time.

Context: Roller massagers are used as a recovery and rehabilitative tool to initiate muscle relaxation and improve range of motion (ROM) and muscular performance. However, research demonstrating such effects is lacking.Objective: To determine the effects of applying a roller massager for 20 and 60 seconds on knee-joint ROM and dynamic muscular performance.Design: Randomized controlled clinical trial. Setting: University laboratory.Patients or Other Participants: Ten recreationally active men (age ¼ 26.6 6 5.2 years, height ¼ 175.3 6 4.3 cm, mass ¼ 84.4 6 8.8 kg).Intervention(s): Participants performed 3 randomized experimental conditions separated by 24 to 48 hours. In condition 1 (5 repetitions of 20 seconds) and condition 2 (5 repetitions of 60 seconds), they applied a roller massager to the quadriceps muscles. Condition 3 served as a control condition in which participants sat quietly.Main Outcome Measure(s): Visual analog pain scale, electromyography (EMG) of the vastus lateralis (VL) and biceps femoris during roller massage and lunge, and kneejoint ROM.Results: We found no differences in pain between the 20-second and 60-second roller-massager conditions. During 60 seconds of roller massage, pain was 13.5% (5.7 6 0.70) and 20.6% (6.2 6 0.70) greater at 40 seconds and 60 seconds, respectively, than at 20 seconds (P , .05). During roller massage, VL and biceps femoris root mean square (RMS) EMG was 8% and 7%, respectively, of RMS EMG recorded during maximal voluntary isometric contraction. Knee-joint ROM was 10% and 16% greater in the 20-second and 60-second roller-massager conditions, respectively, than the control condition (P , .05). Finally, average lunge VL RMS EMG decreased as roller-massage time increased (P , .05).Conclusions: Roller massage was painful and induced muscle activity, but it increased knee-joint ROM and neuromuscular efficiency during a lunge.Key Words: electromyography, pain, muscle activation, flexibility, stretch Key PointsA roller massager applied to the quadriceps at a load equal to 25% of body mass was moderately painful and induced minor contractions. The combination of active contractions and 20 to 60 seconds of roller massage improved knee-joint range of motion and reduced vastus lateralis electromyographic activity during a lunge. Roller massage could be used to increase range of motion during a warm-up or as a complement to stretching during flexibility training sessions. M any researchers have studied how stretching affects range of motion (ROM) and performance; in general, their results showed increased ROM and impairments in subsequent performance.1,2 Recently introduced alternative devices to stretching include the foam roller and roller massager. The use of these devices has produced increases in ROM.3,4 Authors of 2 studies examined how a foam roller affects flexibility.3,5 MacDonald et al 3 reported 12.7% and 10.3% increases in knee-joint ROM at 2 minutes and 10 minutes, respectively, after two 1-minute bouts of foam rolling. MacDonald et al 5 found that quadriceps ROM ...

Motor evoked potentials (MEP) and cervicomedullary evoked potentials (CMEP) may help determine the corticospinal adaptations underlying chronic resistance training-induced increases in voluntary force production. The purpose of the study was to determine the effect of chronic resistance training on corticospinal excitability (CE) of the biceps brachii during elbow flexion contractions at various intensities and the CNS site (i.e. supraspinal or spinal) predominantly responsible for any training-induced differences in CE. Fifteen male subjects were divided into two groups: 1) chronic resistance-trained (RT), (n = 8) and 2) non-RT, (n = 7). Each group performed four sets of ∼5 s elbow flexion contractions of the dominant arm at 10 target forces (from 10%–100% MVC). During each contraction, subjects received 1) transcranial magnetic stimulation, 2) transmastoid electrical stimulation and 3) brachial plexus electrical stimulation, to determine MEP, CMEP and compound muscle action potential (Mmax) amplitudes, respectively, of the biceps brachii. All MEP and CMEP amplitudes were normalized to Mmax. MEP amplitudes were similar in both groups up to 50% MVC, however, beyond 50% MVC, MEP amplitudes were lower in the chronic RT group (p<0.05). CMEP amplitudes recorded from 10–100% MVC were similar for both groups. The ratio of MEP amplitude/absolute force and CMEP amplitude/absolute force were reduced (p<0.012) at all contraction intensities from 10–100% MVC in the chronic-RT compared to the non-RT group. In conclusion, chronic resistance training alters supraspinal and spinal excitability. However, adaptations in the spinal cord (i.e. motoneurone) seem to have a greater influence on the altered CE.

Human studies have not assessed corticospinal excitability of an upper-limb prime mover during arm cycling. The purpose of the present study was to determine whether supraspinal and/or spinal motoneuron excitability of the biceps brachii was different between arm cycling and an intensity-matched tonic contraction. We hypothesized that spinal motoneuron excitability would be higher during arm cycling than an intensity-matched tonic contraction. Supraspinal and spinal motoneuron excitability were assessed using transcranial magnetic stimulation (TMS) of the motor cortex and transmastoid electrical stimulation (TMES) of the corticospinal tract, respectively. TMS-induced motor-evoked potentials (MEPs) and TMES-induced cervicomedullary-evoked potentials (CMEPs) were assessed at three separate positions (3, 6, and 12 o'clock relative to a clock face) during arm cycling and an intensity-matched tonic contraction. MEP amplitudes were 7.2 and 8.8% maximum amplitude of the compound muscle action potential (Mmax) larger during arm cycling compared with a tonic contraction at the 3 (P < 0.001) and 6 o'clock (P < 0.001) positions, respectively. There was no difference between tasks during elbow extension (12 o'clock). CMEP amplitudes were 5.2% Mmax larger during arm cycling compared with a tonic contraction at the 3 o'clock position (P < 0.001) with no differences seen at midflexion (6 o'clock) or extension (12 o'clock). The data indicate an increase in the excitability of corticospinal neurons, which ultimately project to biceps brachii during the elbow flexion portion of arm cycling, and increased spinal motoneuron excitability at the onset of elbow flexion during arm cycling. We conclude that supraspinal and spinal motoneuron excitability are phase- and task-dependent.