ضمن سلسلة علمية دورية تصدر عن التحاد السعودي للتربية البدنية والرياضة للجميع، تتناول موضوعات متنوعة في مجالت التربية البدنية وعلوم الرياضة، ويعدها مجموعة من المختصصين. وتدعو هيئة الشراف على السلسلة المختصصين والمهتمين بمجالت التربية البدنية وعلوم الرياضة، إلى المشاركة في أعداد قادمة بإرسال عناوين موضوعاتهم إلى التحاد مع نبذة مفصلة عن المحاور الرئيسة لكل موضوع
INTRODUCTION: Neuromuscular electrical stimulation (NMES) can be delivered over a muscle belly (mNMES) or nerve trunk (nNMES). Both methods generate contractions that fatigue rapidly due, in part, to non-physiologically high motor unit (MU) discharge frequencies. In this study we introduce interleaved NMES (iNMES), whereby stimulus pulses are alternated between mNMES and nNMES. iNMES was developed to recruit different MU populations with every other stimulus pulse, with a goal of reducing discharge frequencies and muscle fatigue.
Electrical stimulation (ES) induces muscle damage that is characterised by histological alterations of muscle fibres and connective tissue, increases in circulating creatine kinase (CK) activity, decreases in muscle strength and development of delayed onset muscle soreness (DOMS). Muscle damage is induced not only by eccentric contractions with ES but also by isometric contractions evoked by ES.
This study compared between alternating and pulsed current electrical muscle stimulation (EMS) for muscle oxygenation and blood volume during isometric contractions. Nine healthy men (23–48 years) received alternating current EMS (2500 Hz) modulated at 75 Hz on the knee extensors of one leg, and pulsed current EMS (75 Hz) for the other leg separated by 2 weeks in a randomised, counter-balanced order.
This study compared alternating current and pulsed current electrical muscle stimulation (EMS) for torque output, skin temperature (Tsk), blood lactate and hormonal responses, and skeletal muscle damage markers. Twelve healthy men (23-48 yr) received alternating current EMS (2.5 kHz delivered at 75 Hz, 400 micros) for the knee extensors of one leg and pulsed current (75 Hz, 400 micros) for the other leg to induce 40 isometric contractions (on-off ratio 5-15 s) at the knee joint angle of 100 degrees (0 degrees: full extension).
This study compared the first and second exercise bouts consisting of electrically evoked isometric contractions for muscle damage profile. Nine healthy men (31 ± 4 years) had two electrical muscle stimulation (EMS) bouts separated by 2 weeks. The knee extensors of one leg were stimulated by biphasic rectangular pulses (75 Hz, 400 μs, on–off ratio 5–15 s) at the knee joint angle of 100° (0°, full extension) to induce 40 isometric contractions, while the current amplitude was increased to maintain maximal force generation.
Electrical muscle stimulation (EMS) is widely used in rehabilitation and sport training, and alternating current and pulsed current EMS are commonly used. However, no systematic comparison between alternating and pulsed current EMS has been made in the previous studies. The main aim of this research was to compare acute physiological responses between the alternating and pulsed current EMS. The secondary purpose of the research was to investigate further muscle damage induced by EMS-evoked isometric contractions.
