|
|
The importance of research in the arena of sports performance enhancement
cannot be overstated. Anyone can come forth with a technique or theory,
but while guided by the art of coaching experience and performance,
it should be based on science and research to validate its effectiveness.
By holding a technique or theory to the scrutiny of research, we can
more confidently train athletes in way that is safer and more effective.
The following are just some of the research studies from the past
20 years or so which have helped shape the approach at Daisey Physical
Therapy and the Center for Human Performance with regard to enhancing
sports performance. All of these articles are accessible through the
National Library of Medicine at www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed
DETERMINANTS OF PERFORMANCE
Professional
players differ from amateurs in terms of knee flexor (hamstring) muscle
strength and short-distance sprinting speed
Cometti G, et al: Isokinetic strength and anaerobic power of elite,
sub-elite and amateur French soccer players. Int J Sports Med 2001
Jan;22(1):45-51.
Tested 95 soccer players from the French first division (elite), second
division (sub-elite), and amateurs and determined the isokinetic strength
of the knee extensor and flexor muscles at angular velocities from
-120 degrees x s(-1) to 300 degrees x s(-1). Vertical jump, 10 m sprint,
30 m sprint and maximum ball speed during shooting were also measured.
The elite players had higher knee flexor torque than the amateurs
at all angular velocities (p < 0.05), except at 300 degrees x s(-1).
The hamstring/quadriceps ratios proposed with two different methods
were significantly lower in the amateur group than in the elite group
(p < 0.05), except at 300 degrees x s(-1). Maximum ball speed during
shooting and speed over 30 m sprint were not different between elite,
sub-elite, and amateur players while speed over a 10 m sprint was
significantly slower in amateur players and faster in the elite group
(p < 0.05). Although performance in soccer is not determined only
by measurable variables, professional players differ from amateurs
in terms of knee flexor muscle strength and short-distance sprinting
speed. Based on these findings we conclude that hamstring strength
is extremely important in soccer players for joint stabilization during
various tasks, notably in eccentric action. Further, short-sprinting
performance may mirror actual game situations at high level and could
be an important determinant of match-winning actions.
Maximal strength in half squats determines sprint performance and
jumping height in high level soccer players
Wisloff U, Castagna C, Helgerud J, et al: Strong correlation of
maximal squat strength with sprint performance and vertical jump height
in elite soccer players. Br J Sports Med. 2004 Jun;38(3):285-8.
Maximal concentric jump power is related to sprint acceleration
Sleivert G, Taingahue M: The relationship between maximal jump-squat
power and sprint acceleration in athletes. Eur J Appl Physiol. 2004
Jan;91(1):46-52.
Study supporting the speed advantage of gaining a horizontal angle
at first step
Hunter JP, Marshall RN, McNair PJ: Interaction of step length
and step rate during sprint running. Med Sci Sports Exerc. 2004 Feb;36(2):261-71.
The very high step lengths and step rates achieved by elite sprinters
may be possible only by a technique that involves a high horizontal
and low vertical velocity of takeoff.
Which muscles are used for speed? Excellent review of sprinting mechanics
Delecluse C. Influence of strength training on sprint running
performance. Current findings and implications for training. Sports
Med 1997 Sep;24(3):147-56.
Today, it is generally accepted that sprint performance, like endurance
performance, can improve considerably with training. Strength training,
especially, plays a key role in this process. Sprint performance will
be viewed multi-dimensionally as an initial acceleration phase (0
to 10 m), a phase of maximum running speed (36 to 100 m) and a transition
phase in between. Immediately following the start action, the powerful
extensions of the hip, knee and ankle joints are the main accelerators
of body mass. However, the hamstrings, the m. adductor magnus and
the m. gluteus maximus are considered to make the most important contribution
in producing the highest levels of speed. Different training methods
are proposed to improve the power output of these muscles. Some of
them aim for hypertrophy and others for specific adaptations of the
nervous system. This includes general (hypertrophy and neuronal activation),
velocity specific (speed-strength) and movement specific (sprint associated
exercises) strength training. In developing training strategies, the
coach has to keep in mind that strength, power and speed are inherently
related to one another, because they are all the output of the same
functional systems. As heavy resistance training results in a fibre
type IIb into fibre type IIa conversion, the coach has to aim for
an optimal balance between sprint specific and nonspecific training
components. To achieve this they must take into consideration the
specific strength training demands of each individual, based on performance
capacity in each specific phase of the sprint.
Biomechanical analysis of sprinting mechanics
Hunter JP, Marshall RN, McNair PJ. Segment-interaction analysis
of the stance limb in sprint running. J Biomech. 2004 Sep;37(9):1439-46.
During the first-third of the stance phase, a hip extension moment
was the major determinant of the increasing angular velocity of the
thigh
Leg stiffness is related to sprint performance
Bret C, et al: Leg strength and stiffness as ability factors in
100 m sprint running. J Sports Med Phys Fitness. 2002 Sep;42(3):274-81.
The counter-movement jump was related to 100m and was the predictor
of the first phase of the sprint. Athletes who had the greatest leg
stiffness produced the highest acceleration between the first and
the second phases. A hop test was the predictor of the two last phases
of the sprint. A concentric half-squat test was the best predictor
in the 100 m sprint. Leg stiffness plays a major role in the second
phase.
Elite level soccer players are able to sustain, and more quickly
recover from, high intensity intermittent exercise as compared to
amateur or recreational soccer players
Edwards AM, Macfadyen AM, Clark N: Test performance indicators
from a single soccer specific fitness test differentiate between highly
trained and recreationally active soccer players. J Sports Med Phys
Fitness. 2003 Mar;43(1):14-20.
Closed kinetic chain (exercises with the feet on the ground
such as the squat) scores for strength are correlated to vertical
and standing long jump performance, but open chain (i.e. knee extension
exercises) scores are not
Blackburn JR, Morrissey MC. The relationship between open and
closed kinetic chain strength of the lower limb and jumping performance.
J Orthop Sports Phys Ther 1998 Jun;27(6):430-5.
Vertical jump the main predictor of football playing ability
Sawyer DT, Ostarello JZ, Suess EA, Dempsey M. Relationship between
football playing ability and selected performance measures. J Strength
Cond Res. 2002 Nov;16(4):611-6.
TRAINING EFFECTS ON PERFORMANCE
Sled (resisted) sprint training increased the acceleration
phase of sprinting (0-10m). Unresisted sprint training increased the
latter phases of sprinting (20-50m). This implies that different phases
of sprinting require different training techniques.
Zafeiridis A, Saraslanidis P, Manou V, et al: The effects of resisted
sled-pulling sprint training on acceleration and maximum speed performance.
J Sports Med Phys Fitness. 2005 Sep;45(3):284-90.
Closed chain (squat) increased vertical jump by 10% in 6 weeks, while
open-chain (knee ext/hip adduction) had no effect
Augustsson J, et al: Weight training of the thigh muscles using
closed vs. open kinetic chain exercises: a comparison of performance
enhancement. J Orthop Sports Phys Ther 1998 Jan;27(1):3-8
Explosive
training that maximizes mechanical power output is superior to plyometrics
or weight training alone in producing enhancements in performance
variables
Wilson GJ: The optimal training load for the development of dynamic
athletic performance. Med Sci Sports Exerc. 1993 Nov;25(11):1279-86.
This study was performed to determine which of three theoretically
optimal resistance training modalities resulted in the greatest enhancement
in the performance of a series of dynamic athletic activities. The
three training modalities included 1) traditional weight training,
2) plyometric training, and 3) explosive weight training at the load
that maximized mechanical power output. Sixty-four previously trained
subjects were randomly allocated to four groups that included the
above three training modalities and a control group. The experimental
groups trained for 10 wk performing either heavy squat lifts, depth
jumps, or weighted squat jumps. All subjects were tested prior to
training, after 5 wk of training and at the completion of the training
period. The test items included 1) 30-m sprint, 2) vertical jumps
performed with and without a countermovement, 3) maximal cycle test,
4) isokinetic leg extension test, and 5) a maximal isometric test.
The experimental group which trained with the load that maximized
mechanical power achieved the best overall results in enhancing dynamic
athletic performance recording statistically significant improvements
on most test items and producing statistically superior results to
the two other training modalities on the jumping and isokinetic tests.
Simply practicing sprinting at top speed will result in improvements
in 40m time and repeated sprint performance
Dawson B , et al: Changes in performance, muscle metabolites,
enzymes and fibre types after short sprint training. Eur J Appl Physiol
Occup Physiol 1998 Jul;78(2):163-9.
A strength and plyometric program improved power endurance and speed
over aerobic training only. Soccer-specific power endurance training
may improve match performance and decrease fatigue in young female
soccer players Siegler J, Gaskill S, Ruby B: Changes evaluated in
soccer-specific power endurance either with or without a 10-week,
in-season, intermittent, high-intensity training protocol. J Strength
Cond Res. 2003 May;17(2):379-87.
Short-term plyometric training programs increase athletic performances
in prepubescent boys
Diallo O: Effects of plyometric training followed by a reduced
training programme on physical performance in prepubescent soccer
players. J Sports Med Phys Fitness. 2001 Sep;41(3):342-8.
Article supporting the benefits of downhill sprinting
Paradisis GP, Cooke CB.: Kinematic and postural characteristics
of sprint running on sloping surfaces. J Sports Sci. 2001 Feb;19(2):149-59.
- 3 degrees
uphill or downhill compared to a horizontal surface.
- Running speed
was 9.2% faster during downhill compared with horizontal sprint
running, with a 7.1% increase in stride length
- 3.0% slower
during uphill compared with horizontal sprint running with a 5.2%
decrease in stride length, which was associated with significant
changes in posture and reduced flight distance.
Straight-ahead
speed and agility training methods are specific and produce limited
transfer to each other
Young WB, et al: Specificity of sprint and agility training methods.
J Strength Cond Res 2001 Aug;15(3):315-9.
Review
on how resistance training can improve throwing velocity
Derenne C, Ho KW, Murphy JC Effects of general, special, and specific
resistance training on throwing velocity in baseball: a brief review.
J Strength Cond Res. 2001 Feb;15(1):148-56.
VELOCITY SPECIFICTY
The development of coordination is the main explanation
for early gains in velocity specificity
Almasbakk B, Hoff J Coordination, the determinant of velocity
specificity? J Appl Physiol. 1996 Nov;81(5):2046-52.
Velocity specific training does not occur
Cronin J, McNair PJ, Marshall RN: Velocity specificity, combination
training and sport specific tasks. J Sci Med Sport. 2001 Jun;4(2):168-78.
The validity of velocity-specific training and subsequent adaptations
to improve functional sporting performance appears highly questionable,
due to the disparity between training velocity and actual movement
velocity for a given sport specific task such as the netball throw.
High velocity training increased acceleration time and higher
maximum speed. High resistance increased acceleration time only
Delecluse C, et al: Influence of high-resistance and high-velocity
training on sprint performance. Med Sci Sports Exerc 1995 Aug;27(8):1203-9.
Training with light-load jump squats (30% of 1-RM) results
in increased movement velocity capabilities and that velocity-specific
changes in muscle activity may play a key role in this adaptation
McBride JM The effect of heavy- vs. light-load jump squats on
the development of strength, power, and speed. J Strength Cond Res.
2002 Feb;16(1):75-82.
Although velocity-specific strength adaptations have been
shown to occur rapidly in untrained individuals, there is a lack of
velocity-specific performance changes in elite concurrently training
sprint runners performing a combination of traditional and semi-specific
resistance training exercises
Blazevich AJ, Jenkins DG: Effect of the movement speed of resistance
training exercises on sprint and strength performance in concurrently
training elite junior sprinters. J Sports Sci. 2002 Dec;20(12):981-90.
STRETCHING AS IT RELATES TO
PERFORMANCE
Performing PNF stretching before a vertical jump test is detrimental
to performance
Church JB Effect of warm-up and flexibility treatments on vertical
jump performance. J Strength Cond Res. 2001 Aug;15(3):332-6.
Sub-maximum running and practice jumps had a positive effect whereas
static stretching had a negative influence on explosive force and
jumping performance.
Young WB, Behm DG: Effects of running, static stretching and practice
jumps on explosive force production and jumping performance. J Sports
Med Phys Fitness. 2003 Mar;43(1):21-7.
Stretching during the warm-up period for dynamic physical activity
may be counter-productive to vertical jump performance
Knudson, D., Bennett, K., Corn, R., Leick, D., and Smith, C, Acute
Effects of Stretching Are Not Evident in the Kinematics of the Vertical
Jump, JSCR Vol. 15(1), 2001, p. 98-101.
After a 3 minute warm-up on a stationary bike, one half the subjects
rested while the other half performed a series of stretches. Results
indicated that over half the subjects in the stretching group decreased
jumping performance following stretching. It was concluded that warming
up the muscles prior to activity was more beneficial than stretching
before activity.
JUMPING
Drop Jumps of 50 or 100cm improved vertical jump by 4.8cm
and 5.6cm, respectively in junior basketball players
Matavulj D, et al: Effects of plyometric training on jumping performance
in junior basketball players. J Sports Med Phys Fitness. 2001 Jun;41(2):159-64.
Squat-jump training was superior to squat/leg press training
for increasing vertical jump in volleyball players
Newton RU, Kraemer WJ, Hakkinen K: Effects of ballistic training
on preseason preparation of elite volleyball players. Med Sci Sports
Exerc. 1999 Feb;31(2):323-30.
Use of arms in the counter-movement vertical jump increases
velocity of the jump
Feltner ME: Upper extremity augmentation of lower extremity kinetics
during countermovement vertical jumps. J Sports Sci. 1999 Jun;17(6):449-66.
STRENGTH AND HYPERTROPHY TRAINING
Excellent meta-analysis reviewing research optimal training volume,
frequency and intensity
Peterson MD, Rhea MR, Alvar BA: Maximizing strength development
in athletes: a meta-analysis to determine the dose-response relationship.
J Strength Cond Res. 2004 May;18(2):377-82.
Meta-analysis of 37 studies with a total of 370 effect sizes Participants
must have been competitive athletes at the collegiate or professional
level, the study must have employed a strength training intervention,
and must have included necessary data to calculate effect sizes. Effect
size data demonstrate that maximal strength gains are elicited among
athletes who train at a mean training intensity of 85% of
1 repetition maximum (1RM), 2 days per week,
and with a mean training volume of 8 sets per muscle group.
The difference between eccentric and concentric training
Hortobagyi T, Hill JP, Houmard JA, Fraser DD, Lambert NJ, Israel
RG: Effects of concentric and eccentric training on muscle strength,
cross-sectional area, and neural activation. J Appl Physiol. 1996
Mar;80(3):765-72.
- Eccentric
training increased eccentric strength by 46% while concentric
training increased concentric strength by 13%
- Eccentric
training increased concentric strength and concentric training
increased eccentric strength by about the same magnitude (5 and
10%, respectively)
- Type I muscle
fiber percentages did not change significantly, but type IIa fibers
increased and type IIb fibers decreased significantly in both
training groups
- Type II fiber
area increased approximately 10 times more in the eccentric than
in the concentric group
Concluded that
adaptations to training with maximal eccentric contractions are specific
to eccentric muscle actions and are associated with greater neural
adaptation and muscle hypertrophy than concentric exercise.
Eccentric training resulted in greater hypertrophy than concentric
training
Farthing JP, Chilibeck PD: The effects of eccentric and concentric
training at different velocities on muscle hypertrophy. Eur J Appl
Physiol. 2003 Aug;89(6):578-86.
Classic article showing how neural factors and central mechanisms
account for most gains in the first 3 to 5 weeks, with hypertrophy
becoming the dominant factor thereafter.
Moritani T, deVries HA: Neural factors versus hypertrophy in the
time course of muscle strength gain. Am J Phys Med. 1979 Jun;58(3):115-30.
The gluteus maximus, rather than the VL, VMO or biceps femoris,
contributes more as squat depth increases
Caterisano A The effect of back squat depth on the EMG activity
of 4 superficial hip and thigh muscles. J Strength Cond Res. 2002
Aug;16(3):428-32.
The physical change in athletes since 1987
Secora CA, Latin RW, Berg KE, Noble JM: Comparison of physical
and performance characteristics of NCAA Division I football players:
1987 and 2000. J Strength Cond Res. 2004 May;18(2):286-91. Westside
High School, Omaha, Nebraska.
Normative data from present Division I National Collegiate Athletic
Association football teams to those from 1987. Division I college
football players in general have become bigger, stronger, faster,
and more powerful.
Abdominal training articles showing…
- No difference
between the typical gym/mat exercises in terms of how much they
stress the abdominals
- Regarding
crunches, there is no difference in abdominal activation whether
the feet are on the floor or elevated, whether the hips/knees
are straight or flexed, whether the subject is lying on an incline,
or whether they are performing a sit-up or a crunch.
- Exercises
in which the legs are pulled toward the chest while performing
a crunch, or ones that involve lowering the legs, have been shown
to increase the overall activity of the abdominal muscles beyond
what only a crunch exercise will activate.
1. Willett
GM, et al: Relative activity of abdominal muscles during commonly
prescribed strengthening exercises. J Strength Cond Res 2001 Nov;15(4):480-5.
2. Guimaraes AC, et al: The contribution of the rectus abdominis and
rectus femoris in twelve selected abdominal exercises. An electromyographic
study. J Sports Med Phys Fitness 1991 Jun;31(2):222-30.
3. Sarti MA, et al: Muscle activity in upper and lower rectus abdominus
during abdominal exercises. Arch Phys Med Rehabil 1996 Dec;77(12):1293-7.
4. Warden SJ, Wajswelner H, Bennell KL: Relative activity of abdominal
muscles during commonly prescribed strengthening exercises. J Strength
Cond Res 2001 Nov;15(4):480-5.
5. Shields RK, Heiss DG: An electromyographic comparison of abdominal
muscle synergies during curl and double straight leg lowering exercises
with control of the pelvic position. Spine 1997 Aug 15;22(16):1873-9.
Incline press effectiveness
1. Barnett C, Kippers V, Turner P: Effects of variations of the
bench press exercise on the EMG activity of five shoulder muscles.
J Strength and Conditioning Research, 1995; 9(4):222-227.
2. Clemons JM, Aaron C: Effect of grip width on the myoelectric activity
of the prime movers in the bench press. J Strength and Condition Research
1997, 11(2), 82-87.
Showed no difference between incline press and flat bench press in
terms of clavicular head of the pectoralis activity. Close grip bench
created the most clavicular head activity through its shoulder flexion
action. |
|
