Beginning exercisers who performed strrength training repetitions more slowly experienced significantly greater strength gains.
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Beginning exercisers who performed strrength training repetitions more slowly experienced significantly greater strength gains.
A few years ago, another researcher and I published the results of a study featuring beginning exercisers who performed strength training at either a faster repetition speed (7 seconds each) or a slower repetition speed (14 seconds each). We found that the subjects who performed their repetitions more slowly experienced significantly greater strength gains.1
We concluded that slower repetition speeds were preferable to faster repetition speeds for strength development, presumably due to less momentum and more muscle stimulus. While this may be true, it is possible that other factors influenced our findings. First let's examine the similarities and differences between the two training protocols.
Protocol similaritiesSimilarity No. 1. Both exercise protocols required the same time under load for completion of the exercise set. Group 1 performed an average of 10 repetitions (ranging from eight to 12) in seven seconds each for a 70-second exercise set. Group 2 performed an average of five repetitions (ranging from four to six) in 14 seconds each for a 70-second exercise set.
Similarity No. 2. Both exercise protocols used a four-second eccentric muscle action on each repetition. Group 1 performed a two-second lifting (concentric) movement, paused one second in the position of full muscle contraction, and then performed a four-second lowering (eccentric) movement. Group 2 performed a 10-second lifting (concentric) movement followed by a four-second lowering (eccentric) movement.
Protocol differencesDifference No. 1. The subjects in Group 1 spent less time in each concentric muscle action than Group 2. As noted above, Group 1 executed two-second lifting (concentric) movements, whereas Group 2 performed 10-second lifting (concentric) movements.
Difference No. 2. The subjects who performed 10-second lifting movements reported more training discomfort than the subjects who executed two-second lifting movements. In fact, only two of the 147 study subjects chose to train with 14-second repetitions after the study was completed, even though the slower repetition speed produced superior results.
It is notable that the Group 1 subjects spent approximately 30 percent of each repetition in concentric muscle action, whereas the Group 2 subjects, who attained greater strength gains, spent approximately 70 percent of each repetition in concentric muscle action. Based on this observation, I decided to take a closer look at the concentric action time versus the eccentric action time in repetitions of equal duration. Because beginning exercisers appear to be more comfortable with moderate-speed repetitions compared to slow-speed repetitions, I chose a six-second repetition speed for this study.
Study particularsFor this study, 54 women were randomly assigned to one of two training protocols. All of the subjects performed eight to 12 arm curls to the point of muscle fatigue on a Nautilus biceps curl machine equipped with a Fitness Advisor computer. The computer provided visual and audible guidance for each lifting (concentric) and lowering (eccentric) movement. Twenty-eight women performed six-second repetitions with a shorter concentric muscle action (two seconds lifting and four seconds lowering). They spent approximately 33 percent of each repetition in concentric muscle action. Twenty-six women performed six-second repetitions with a longer concentric muscle action (four seconds lifting and two seconds lowering). They spent approximately 66 percent of each repetition in concentric muscle action.
All of the subjects were assessed isometrically (via Microfit computer) for maximum biceps strength (90 degrees elbow flexion) before and after the 10-week training program. On average, the women who executed two-second concentric muscle actions increased their biceps strength by 9 pounds, and the women who executed four-second concentric muscle actions increased their biceps strength by 12 pounds (see Figure 1). Although data analyses fell slightly short of statistical significance (p<0.06), six-second repetitions performed with longer (four-second) concentric muscle actions compared favorably with six-second repetitions performed with shorter (two-second) concentric muscle actions, and may prove to be more effective for strength development over longer training periods.
Study resultsWhile our preliminary research project requires replication studies, there appear to be advantages to spending a higher percentage of each repetition on the concentric muscle action. First, consider that muscles can produce more force output during eccentric actions than during concentric actions. That is, with a given weightload, the lifting movement is more difficult than the lowering movement. Second, consider that muscles can produce more force output during slower speeds than during faster speeds (see Figure 2). Consequently, it may make sense to use a slower speed during the more difficult lifting (concentric) action, and to use a faster speed during the easier lowering (eccentric) action.
Although our research has not shown six-second repetitions to be more effective than other controlled movement speeds, most people find this to be a comfortable repetition cadence.2 Of course, six-second repetitions have been widely used in fitness facilities since Arthur Jones recommended this exercise speed in 1970. Let me suggest that instead of always asking clients to perform six-second repetitions in a two seconds up and four seconds down format, you occasionally have them perform six-second repetitions in a four seconds up and two seconds down format. You may find, as did our study subjects, that this is a highly productive strength training protocol. Clients will still complete 10 repetitions in 60 seconds, but 40 seconds (rather than 20 seconds) will be used for the more challenging concentric muscle actions.
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Balazs Pull-Up Bars are constructed of heavy gauge steel with durable Nu-Black powdercoat finish, featuring Shur-Grip foam-covered bars. They are available as fixed or adjustable, in 32- or 48-inch widths, and are made in the U.S. Adjustable Pull-Up Bars have stainless steel supports, and spring loaded "popper pins" for smooth and easy adjustment - accommodating a wide range of users. The frame is 11-gauge steel tubing with an 18-inch height adjustment range. Non-Adjustable Pull-Up Bars are constructed of heavy-gauge steel and 11-gauge steel tubing, with two bar depths of 12 or 18 inches away from the wall.
Body Bar Systems Inc.
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The Body Bar Flex is a flexible fiberglass-composite rod with an easy-to-grip soft rubber casing. Weighing approximately 1 pound, the rod is available in 3- and 4-foot lengths. It can be used for balance and stretching when straight, but offers resistance of up to 10 pounds when bent into an arc. Full-joint range-of-motion exercises work the entire body in simple or compound movements to develop strength, flexibility, coordination and balance.
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The Pro-Dual commercial equipment line offers modular flexibility developed specifically to address the needs of facilities with limited space. It includes 10 function-specific dual machines that can stand alone or in combination with a three- or four-stack weight tower to build a single multifunction gym.
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CorePole delivers strength and cardio training in one workout, from one to up to 15 participants simultaneously, from beginners to people training competitively. Made of durable cold-rolled steel, the system comes with 20 resistance bands of varied strengths, and offers a full range of motion with 360-degree rotation around the pole with six anchor height points.
Cybex International Inc.
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efi Sports Medicine
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efi Sports Medicine's GTS machine makes Pilates accessible for every fitness level. GravityPilates employs the GTS's incline glideboard and cable pulley system, using body weight as resistance to produce a feeling of stretch and constant resistance throughout the entire motion of every exercise. GravityPilates instructors can adapt exercises by adjusting the level of the GTS incline.
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The 325 Functional Wall Pulley requires minimal space. A multitude of exercises - including lat pull-downs, bicep curls and chest flies - can be performed. Features include a 75-pound weight stack in 5-pound increments; swivel handles for a wide range of motion; and adjustable, rotating arms. The rotating arms adjust from ground level to 7 feet - 90 degrees horizontally and 180 degrees vertically - to maximize exercise versatility.
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Kraiburg solid rubber weight plates fit all Olympic standard bars. They reduce noise and damage to floors, and are constructed of 100 percent solid rubber. Each weight comes with an anti-rust metal bushing. They are available in black and Olympic colors, and are designed for easy care, and feature smooth solid rubber. All plates are 17.7 inches in diameter.
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GP Industries Inc.
800 814-4943; www.gpindinc.com
New urethane dumbbells from GP Industries feature a solid design with a Uni-Lock handle, available in either a straight or tapered handle design. The urethane coating is designed for durability against wear. All weight increments are permanently engraved in white urethane and will not discolor or rub off. Weights range from 5 to 150 pounds in 5-pound increments. A half-size set - from 7.5 to 27.5 pounds - is also available.
Hampton Fitness Products Ltd.
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Satellite SeriesT dumbbells feature Gel-GripT urethane handles and a durable, comfortable grip. The rack features weight labels for easy return, and is ergonomically angled for safe lifting.
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Selectorized strength equipment modules from Hardkore can stand alone, or accommodate a particular circuit routine. All Cyber-Racks, including the new Dual Power Station, incorporate the Life-Link self-spotting safety system. Safety pins on the HK130A drop out automatically when the sled is moved upward, and have a stopping point to prevent injury at the bottom of the movement. The HK150 Smith machine is counter-balanced to 15 pounds, and has adjustable positive stops. V-formed plate construction ensures correct mass at stress points, where additional structural integrity is necessary.
Hoist Fitness Systems
800 548-5438; www.hoistfitness.com
The Roc-It Leg Press RS-1403 has 11 linear seat adjustments to accommodate varying leg lengths, a large oval foot plate that provides multiple foot placements for both leg press and calf exercises, and starts a user's body in the traditional leg press position, then rocks the upper torso rearward to provide greater activation of the gluteal muscles.
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The Power Strength Xi2 allows users to define their path of motion when performing strength exercises. This commercial unit features dual weight stacks, arms that adjust in both vertical and horizontal planes, dual pulley head design for better cable tracking and a compact footprint. It has an electrostatic, powdercoated, fully welded tubular 11-gauge steel frame and 3/16-inch cable. A selection of standard colors are available, including white, black, silver, charcoal and platinum.
866 996-3825; www.intekstrength.com
Intek Strength offers a variety of strength products, including solid steel urethane-encased dumbbells; Pro rubber, Pro steel and Pro urethane dumbbells; straight and curl fixed barbells; and Olympic plates in urethane, rubber and steel. All have patent-pending, ergonomic slots for gripping comfort.
Iron Grip Barbell Company
800 664-4766, www.irongrip.com
Made exclusively in the U.S., Iron Grip's urethane-encased solid steel dumbbells and fixed barbells feature a urethane coating that won't mar equipment, walls or floors, and heavy-duty welded construction. The welded construction and injection-molded exterior results in a dumbbell that is much shorter in length than pro-style dumbbells. This compact design makes urethane dumbbells easy and safe to handle. They also feature 12-sided, anti-roll heads with stable, flat, tip-resistant ends. Easy-to-read weight markings are permanently engraved and bonded into the surface.
Ivanko Barbell Company Inc.
800 247-9044; www.ivankobarbell.com
E-Z Lift urethane plates are round for the safe and proper execution of floor exercises, such as repetition power cleans and dead lifts. Ivanko's urethane dumbbells feature a no-bolt/no-weld system that affixes the head to the handle. Logos can be engraved onto plates and dumbbells.
800 888-7009; www.keiser.com
The Infinity series unilaterally and bilaterally works muscle groups safely at any angle, resistance or speed through a user's range of motion. Resistance is consistent and unaffected by speed of the exercise. By using Keiser's free-moving pneumatic technology, users can safely increase their power output as speed increases. This allows for intense functional workouts without shock load to muscles, connective tissues and joints.
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The Hammer Strength Olympic Heavy-Duty line, including the new Combo Rack and 6-by-8-foot lifting platform, offers facilities a comprehensive selection of performance-enhancing training products. The rugged, space-efficient Combo Rack lets two athletes train simultaneously, while the lifting platform features full subfloor framing, a finished oak surface and rubber impact mats.
Magnum Fitness Systems
800 372-0554; www.magnumfitness.com
The new 5000 Series of selectorized machines features large, round, bent tubing blended together into a low profile, with fully guarded pulleys and full rear shrouds. The 5000 Series has integrated Magnum's Biangular technology of multi-plane movement with optimally positioned weight stacks, and easy-to-reach and -use supplemental resistance and range-of-motion controls.
925 337-4205; www.marpokinetics.com
The Viper Rope Climber provides an upper-body strength workout, and eliminates the need to use separate machines to exercise different muscle groups. Its levitating seat with a counter-weight stack provide a simulation of rope climbing. Seven resistance settings and up to 250 pounds of weight assistance make Viper accessible and effective for a wide range of users. Keeping users close to the ground eliminates safety concerns associated with ceiling ropes. A small footprint and no electricity requirements maximize floor space. The rope is soft, yet durable.
Matrix Fitness Systems
866 693-4863; www.matrixfitness.com
Matrix provides its customers with a full line of selectorized strength equipment in an aesthetically appealing package. The strength equipment features oversized grips; towel and cup holders; ergonomic seating; extra-strong, round-form tubing; automotive-quality powdercoat finish; and color-coded adjustments that can be made from the exercise position.
866 814-0719; www.corespinalfitness.com
The Core Spinal Fitness System by MedX focuses on four spinal health factors: strength, stability, flexibility and endurance. The research-based system includes a series of five biomechanically precise machines designed to isolate and strengthen the lower back, neck and torso muscles.
800 675-0171; www.nautilusone.com
The Nautilus One commercial strength circuit features a simple dial that allows users to adjust weight quickly in 5-pound increments, up to 400 pounds, while concealing the actual amount of weight moving inside the tower. The patented resistance engine features a horizontal weight stack that delivers smooth, nearly frictionless movement. Gas-assisted technology helps users quickly adjust the seat, and an educational placard on each unit features holographic photography to visually illustrate how to perform the exercise. The line has one consistent look and feel, since the low-profile tower is identical on each of the 14 stations in the circuit.
Paramount Fitness Corp.
800 721-2121; www.paramountfitness.com
Paramount designs and manufactures a full range of strength-training products. The 17-piece SP Circuit combines ergonomics, biomechanics and structural performance with contemporary aesthetics. Designed using parametric modeling, each unit fits a wide range of users comfortably, while extensive testing at or above maximum field applications assures long-term durability with minimal service requirements. All SP models meet or exceed ASTM and EN957 safety design standards for fitness equipment.
800 321-6975; www.power-systems.com
The Pro Power Pro Trainer Six-Station gym includes a cable crossover, two lat pulls, two low rows and a chin-up bar. The 11-gauge steel tubing frames have a baked-on, powdercoated finish, and the cable crossover has two fully assembled 200-pound weight stacks. Low rows have a 12-by-32-inch elevated seat, lat pulls have an adjustable knee roller pad, and both have 225-pound fully assembled weight stacks. Two 48-inch lat bars, two low row double handles, two single handles and two ankle straps are included. Custom embroidery is available, along with two frame and 25 upholstery colors.
800 786-8404; www.precor.com
The Precor Icarian line of commercial strength equipment features more than 100 products in six categories, including machine-defined selectorized, user-defined selectorized, multi-stations, plateloaded, free weight equipment, and benches and racks. A redesigned selectorized line incorporates enhanced aesthetics and user-friendly features, with new elevated weight stacks and sleek shrouds. Precor Icarian Modular System components can be connected in virtually any configuration, with more than 100 pre-configured layouts of two- to 12-stack configurations. Precor Icarian equipment features 2-by-4-inch steel frames and high-quality pulleys and cables.
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Kids PACE Express (Kids PE) hydraulic resistance equipment is for children ages five through 11, and the PACE hydraulic circuit training program is for adults. Kids' packages include a Kids PE marketing/promo package, NESTA certification and accessories. Adult packages include an onsite PACE certification and marketing/promo package. Both programs are designed to be non-intimidating, effective, safe and fun.
Quantum Fitness Corp.
800 937-2282; www.quantumfitness.com
The patented Power Quad strength machine presents a closed kinetic way to isolate the quadriceps for fully functional rehabilitation of knee injuries, or to simply exercise the quadriceps. This is achieved by the pivot-seat design, which locks the hip angle for complete isolation, and is designed to offer greater muscle activation than with a leg extension. The Power Quad features a seat back adjustment to control knee flexion, non-encumbered walk-in design and extra large, non-slip foot plates.
800 363-2671; www.rtfit.com
The Rotary Torso Bench is designed to eliminate spinal compression while improving disc alignment. With legs partially extended, users' abdominal musculature is placed in an optimal strengthening position during rotation. In addition, a proprioceptive element is added to the exercise when users rotate in either direction with a loosened grip on the handles to engage core stabilizer muscles. The RT/AB/BACK option turns the torso bench into a three-in-one core combination unit.
800 709-1400; www.sportsartfitness.com
The SportsArt Fitness selectorized strength line features a leg press that allows the user to maneuver the machine between a traditional leg press position and a hack squat position, or anywhere in between, with a pull of a lever. In addition, the heavy-duty non-skid footplate includes side step foot rests for in between sets. Adjustment levers are color-coded and located within easy reach of the user. Contoured upholstery, Kevlar belts, magnetic selector pins and fully shrouded weight stacks are other features.
800 228-6635; www.startrac.com
Star Trac offers user-focused strength equipment, including the HumanSport series, a line of six functional training strength machines. Each machine represents two traditional cable-motion pieces within one compact unit, facilitated by a dual-independent weight stack system. The versatile pieces feature distinctive styling, one-touch adjustment and swivel pulleys to ensure a smooth and unlimited range of motion. The space-saving HumanSport line offers users a diverse range of training options to explore new self-driven or personal trainer-led training techniques.
800 370-3307; www.strengthequipment.net
The Five-Station Unit features a seated lat with a 250-pound weight stack, low pulley row with 300-pound weight stack, adjustable pulley column cable crossover with two weight stacks of 200 pounds each (100-pound resistance) and a chin-up bar. It is constructed of 3-inch square tubing with 6-inch ballbearing pulleys, and has a ballbearing swivel on the adjustable crossover pulleys. The Five-Station Unit has heavy duty foam padding and adjustable height on the low pulley row. All handles are included.
800 368-6448; www.strivefit.com
Smart Circuits feature Strive's patented Smart Strength technology. The strength line is installed in commercial fitness centers, YMCAs, sports performance centers, rehab facilities and U.S. military fitness facilities, and used by celebrity trainers.
800 804-0952; www.technogymusa.com
PureStrength plateloaded equipment is designed to offer biomechanics that maximize muscle activation while respecting the safest trajectory for the joint. Ergonomic features include Pure Grip technology, a comfortable and natural grip design to fit all users. The Body Print System ensures the seat molds to the user's body shape for maximum support. Other features include Visual Flags and spring-loaded seat adjustments to help users find the right exercise position.
Troy Barbell &Fitness
800 872-7767; www.troybarbell.com
The new Troy solid-steel, urethane-encased dumbbell ends are press-fit and welded to a hard chrome, 32-millimeter straight handle that is finely knurled for a firm, comfortable grip. The head of each dumbbell is fully encased with polyurethane. The dumbbells are designed to maintain a 2 percent accuracy level.
805 804-577; www.4truform.com
The IsoBar line of commercial weight bars uses patented sliding hand grips that are linked, thus remaining equidistant from the center of the bar for balance, symmetry and control. IsoBar combines the range of motion, isolation, variation and muscle recruitment afforded by dumbbells, with the control, simplicity and racking ability of barbells. Cable-attachment units also are available.
Vortex Fitness Equipment
877 676-4677; www.vortexfitness.com
Vortex Fitness Equipment teamed up with HiTech Trainer and Dr. Brian Biagioli of the National Council on Strength and Fitness to produce a set of functional, sport, ADL and circuit training programs. The Vortex 30-Pack and HiTech Trainer offer pre-designed and customizable programs, meal and weight-loss programming, and the ability to track clients' results and scheduling online.