A review of blocking in volleyball: from the notational analysis to biomechanics

Abstract

This article reviews the state of art of the research concerning the biomechanics of blocking in volleyball. Since it is fundamental to link the “reality of the game” (what happens in the field) with laboratory simulations, the logic procedure to investigate this skill followed this progression: 1) the importance of block in the game was analyzed in terms of relationships with the match results. 2) Blocking footwork techniques were classified and data relative to the frequency of blocking to stop the opponents attack were collected and analysed. 3) Kinematical analyses of blocking techniques were performed in the laboratory of the Faculty of Exercise and Sport Science at the University of Bologna, Italy. These results allow coaches to adjust the tactic in the game, to differentiate the type of drills and to develop some special exercises to train players for the improvement of their blocking technique.

Full text

Journal of Human Sport & Exercise Vol IV No II 2009 93-99
A REVIEW OF BLOCKING IN VOLLEYBALL: FROM THE NOTATIONAL
ANALYSIS TO BIOMECHANICS
Roberto Lobietti
1
1
Faculty of Exercise and Sport Science, University of Bologna, Italy
Received: 12 November 2008; received in revised form: 15 January 2009; accepted: 20 February 2009
ABSTRACT
This article reviews the state of art of the research concerning the biomechanics of
blocking in volleyball. Since it is fundamental to link the “reality of the game” (what happens
in the field) with laboratory simulations, the logic procedure to investigate this skill followed
this progression: 1) the importance of block in the game was analyzed in terms of
relationships with the match results. 2) Blocking footwork techniques were classified and data
relative to the frequency of blocking to stop the opponents attack were collected and analysed.
3) Kinematical analyses of blocking techniques were performed in the laboratory of the
Faculty of Exercise and Sport Science at the University of Bologna, Italy. These results allow
coaches to adjust the tactic in the game, to differentiate the type of drills and to develop some
special exercises to train players for the improvement of their blocking technique.
Key words: stereophotogrammetry, block, lateral movement, kinematics
Reference Data: Lobietti R. A review of blocking in volleyball: from the notational analysis
to biomechanics. J. Hum. Sport Exerc. 2009; 4(2):93-99
Corresponding author. Facoltà di Scienze Motorie, via San Vitale, n. 15 - 40125 Bologna.
E-mail: roberto.lobietti@unibo.it
© 2009 University of Alicante. Faculty of Education.
DOI:10.4100/jhse.2009.42.03
Journal of Human Sport and Exercise online
J. Hum. Sport Exerc.
Official Journal of the Area of Physical Education and Sport
Faculty of Education. University of Alicante. Spain
ISSN 1988-5202 / DOI 10.4100/jhse
An International Electronic Journal
Volume 4 Number 2 July 2009
Review Article

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© 2009 University of Alicante. Faculty of Education. ISSN 1988-5202
INTRODUCTION
Blocking successfully is a crucial feature of winning teams in today’s volleyball. Key points
for the effectiveness of block are anticipation, decision-making, movement speed and
jumping ability. In this article I will review the state of art of the research concerning this
important skill. A particular focus will be onto some studies recently performed at the
University of Bologna, Italy, in which the block has been analysed following three main
perspectives:
•The importance of this skill to win.
•The types of movement most frequently used by players for blocking, investigated
with a technical analysis.
•The biomechanics of the block and of the vertical jump.
To block efficiently players should use a technique allowing the shortest time to arrive at the
target (the ball-contact), the longest lateral movement along the net and a vertical jump. Also
penetration and angulation of the hands relatively to the net plane are determinant to form an
efficient surface over the net and to control the rebound of the ball. This is the reason for
which coaches (Beal & Crabb, 1987; Kiraly, 1990; Paolini, 1998) consider the “frontality” of
the body with respect to the net as an important factor: pelvis and shoulders should be parallel
to the net as much as possible.
Previously few studies have compared different footwork techniques for the lateral movement
sequence in volleyball blocking.
The two principal types of footwork techniques are the “slide or 2 step” and the “cross-over or
three step”. To better explain these movement in figure 1 and 2 are described the feet’s
actions of a blocker moving to the right.
In the slide step (figure 1) the right foot moves laterally and the left foot follows close to the
leading foot, than the feet push up for the jump.
Figure 1. Slide step
In the cross over step (figure 2) the left foot first crosses over the right foot passing closer to
the net and than the right foot closes the move crossing back, then both feet push up for the
jump. Frequently the cross-over follows a previous short slide of the right foot: for that reason
the name of a “three step technique”.

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© 2009 University of Alicante. Faculty of Education. ISSN 1988-5202
Figure 2. Cross over step
Cox et al. (1982) analysed the temporal variables of the lateral movement to the right using a
pair of pressure sensitive floor mats. The authors (Cox, Noble, & Johnson, 1982) compared
three different techniques: the cross-over and the jab cross-over (slide-cross and slide again)
were better than the slide step in terms of getting the blocker off the ground and getting into
the proper blocking position quickly.
Kwak et al. (1989) compared the cross-over and the slide steps used by female (14) and male
(10) Korean players in terms of horizontal velocity, maximum vertical take-off velocity and
maximum vertical ground reaction force. The systems used were cinematography and a force
platform. Their findings showed no differences in females, while the cross-over step resulted
more effective in males.
Buekers (1991) built a special apparatus with two pressure sensitive floor mats and a
photocell system analysing temporal data from the feet start and the hands arrive over the net.
In this way they analysed the performance of 10 female players moving from the middle of
the court to the right side. The author stated that the optimal step technique should vary as a
function of the lateral distance that must be covered by the blocker. Therefore, the slide step is
the best in case of a short distance while the cross-over is better suitable when the opponent’s
attack is far away (Buekers, 1991).
Vint (1997) analysed these studies and built a complete deterministic model of the block. He
also proposed a qualitative analysis with a film blockers performed with two synchronized
cameras. In his work, some key points determinant for the technical effectiveness of the block
were identified: time from start to the contact with the ball, angulation and penetration of the
hands, body position relative to the net in the flight phase of the block, and elevation of the
jump.
Lehnert et al. (2001) performing a 3D videography (APAS) of only two male middle blockers
(going to the right) stated that dropping hands during lateral displacement positively affects
the kinematic characteristics of the movement (velocity of the movement and block jump
height).
All these studies fixed the distance that the players had to cover laterally (2,70 m for Cox and
Kwak, 3,00 m for Buekers), collected temporal data to arrive to the target from the starting
positions (Cox et al., 1982; Kwak et al., 1989), and computed mean horizontal velocity
(Kwak et al., 1989). Since the distance that players have to cover laterally is not a constant but
depends on starting position and players’ specialisation, a different approach in the
kinematical analysis was followed in our pilot studies:

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• The first study was limited to the analysis of the lower limb of 6 players moving to
both the directions (left and right) and using 4 types of footwork techniques (Lobietti
et al., 2005).
• The second study focused on the vertical jump to block the Quick Attack (Lobietti et
al., 2006).
The Notational Analyses
• The importance of the block to win the game has been investigated with a cluster
analysis comparing the male (M) and female (W) Italian Volleyball Professional
League (Lobietti et al., 2006). The investigation analysed the performance using the
software Data Volley collecting points scored per set serving, attacking and blocking
or by means of opponent’s error. This study showed that, for male players, the block
resulted the second skill in importance after the attack: block’s points per set were
highly correlate with the final ranking (R=0.74).
• Blocking footwork techniques were classified and data relative to the frequency of
blocking to stop the opponents attack were collected by means of an observational
analysis. The blocking movements were classified watching a film realised from a
central position back the court with a video-camera (25 Hz). The types of movement
most frequently used by players resulted the vertical jump (20% W and 16% M), the
jump to block after one or more slide step (43% W and 45% M) and a combination
of cross-over step (22% W and 36% M) (Lobietti & Merni, 2006).
Instrumentation used for the kinematical analyses
A system for three-dimensional analysis of motion (Vicon Motion System) has been used.
Passive markers fixed to different anatomical landmarks of joints during blocking exercises
were filmed with 6 infra-red video cameras with a max resolution of 300.000 pixels and a
frequency of 100 Hz. The system uses stereophotogrammetric procedures to create a 3-D
image.
First Study (Lobietti et al. 2005)
Subjects: six (4 hitters, 1 middle blocker, 1 setter) male volleyball players (age 26.8±5.5
years, height 189.6±5.5 cm, weight 83.4±4.1 Kg, all right handed).
Each player executed 4 trials of each type of movement: one (SS) and two consecutive slide
(DSS), a single cross step (CS) and a slide-cross (SCS) in both directions. The players were
asked to reach the best speed, the longest distance, the maximal elevation and verticality of
the jump, maintaining the best frontality at the net.
The great differences with the real game was the absence of the ball, of the opponents and the
possibility for players to start by themselves rather than reacting at situations, so we have to
consider the following results as a description of a typical blocking drill session. A single trial
of each player on each footwork technique for both directions has been selected.

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Table 1. Elevation and the mean value of duration of the different phases of the move: the data regarding
support and pivot foot contact time are very interesting for coaches to select special exercises reproducing or
reducing this time.
Blocking
footwork
technique
Time
of the
last
step
pivot
foot
contact
time
Time of
the
closing
step
Support
foot
contact
time
Time of
the jump
Total
time
Vertical
speed
at jump
foot off
Elevation
sec sec sec sec Sec sec m/sec Mm
SCS
0,526 0,369 0,340 0,175 0,677 1,977 3,767 557
CS
0,436 0,408 0,318 0,203 0,663 1,519 3,471 532
SS
0,464 0,450 0,331 0,249 0,632 1,558 3,059 474
DSS
0,447 0,419 0,352 0,210 0,613 2,076 3,069 458
Mean
0,468 0,412 0,335 0,209 0,646 1,783 3,279 505
St. Dev.
0,061 0,056 0,049 0,046 0,040 0,263 0,307 72
Min
0,360 0,310 0,250 0,120 0,580 1,320 2,463 367
Max
0,570 0,540 0,470 0,310 0,750 2,260 4,061 662
Mean values of frontality at jump foot off confirmed that the orientation of the body was not
so far to be parallel to the net by these players: SCS 18±11 deg; CS 21±19 deg; SS 7±5 deg;
DS 5±3 deg.
The lateral shift of the body during the flight (verticality) in the jump showed a mean value of
about 28 cm using the two types of cross techniques and about 10 cm using the slide.
This study suggested to coaches some adjustment for the players: outside blockers should use
the CS when they are moving to outside and to use SS to the middle; middle blockers should
use mostly the SCS or CS.
These players were faster to the left: thanks to the results of the study they changed their
strategy in game. When starting to block in position 4 they can start closer to the middle of
the court helping the middle blocker, whereas in position 2 they had to start a little bit wider
to be ready against the opposite outside hitter.
Second Study (Lobietti et al. 2006)
Subjects: Four male volleyball players (age 16.5±1 y, height 182.7±2.8 cm, weight 72±5 Kg)
of an under 18 team were filmed during the execution of vertical jump simulating the two
types of tactic used to block the quick attack. In the Read Block System (RBS) the blocker
starts close to the net looking at the opponent’s setter, with hands up and bent legs. He is
ready to react jumping vertically from this position, in case of a quick set, or to move his feet
and follows the ball, in case of an outside set. Outside blocker (OB) starts also ready to help
the MB against the quick set or to move laterally against an outside set in front of him. In the
Commit Block System (CBS), the MB has to jump at the take off of the quick hitter’s spike
without worrying about the set. In the simulation of this two situations in the laboratory of
biomechanics, the blocker starting close to the net had to execute the block trying to reach the
maximum elevation of the jump and the maximum hands’ penetration. In the CBS, the player
decided by himself when to jump. In the RBS, the player was ready to react, reading the

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coach miming the opponent setter in all the three possible directions (left, right, or up) and
then moved or jumped consequently. Three trials for each type of block were acquired and the
best trial was identified as the execution with the maximum elevation for the CBS and with
the shortest reaction time for the RBS.
In table 2 are reported data relative to the different phases of the block, elevation and
penetration angle for both the types of tactic.
Table 2. Durations, distances and velocity (Mean±SD)
Preparatory
phase
(sec)
Push-off
phase
(sec)
Flight
phase
(sec)
Hands time to
arrive over the
net (sec)
Elevation of
the COM
(cm)
Penetration
Angle
(deg)
CBS 0,38±0,14 0,32±0,05 0,60±0,01 0,75±0,15 442±29 135±7
RBS 0,18±0,20 0,22±0,07 0,56±0,02 0,43±0,30 364±34 141±2
A non-parametric Friedman test was performed to analyse the differences between the two
types of techniques. In the RBS, the elevation was lower, the arms extension allowed the
hands to arrive over the net in a shorter time. The quantitative analysis of upper limbs showed
a similar penetration, although reached with different movement strategies, In the CBS, a
countermovement allowed to jump higher. This can be explained by the eccentric preload of
hip extensors). On the other hand, the starting position of the RBS requires directly to jump
without any countermovement. As observed by Komi (1983), the countermovement jump
allows the athletes to perform a higher jump compared to the squat jump. However, the lower
elevation of the RBS was compensated by a shorter time necessary for the hands to arrive
over the net.
A limit of this study, as well as all previous studies, was the absence of the ball and of the
attackers but these results could help coaches to teach and train the blockers better.
CONCLUSION
One of the most interesting results of these studies was relative to the countermovement
before the jump:
• In the Vertical jump of the Commit Block at the moment of the maximal flexion the
knee angle was around 90 degree.
• In the lateral movement (slide and cross) the value of the knee angle of the pivot foot
was around 90 degree.
These evidences suggest coaches to use this angle in all the exercises of weight -or jump-
training proposed to improve blocking abilities.
Volleyball is an open skill sport and for this reason the variability of the movement is very
high. Therefore, the biomechanical studies have to follow notational analyses and qualitative
descriptions of the skills. Blocking was ranked as the second skill in importance to win the
game; the most popular techniques used by players in matches to block resulted the simple
vertical jump, the slide and the cross over step. The stereophotogrammetry permitted to

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© 2009 University of Alicante. Faculty of Education. ISSN 1988-5202
investigate the kinematics of the block and after the classification of the frequency of different
type of technique and tactic used by players was possible to standardize the researches. Due to
the importance of the lateral speed in the footwork techniques and jump’s height to determine
blocking efficiency, the investigations conducted and published focused mostly on the
kinematics of the lower limb. The results presented in this article are the first step of a major
project: further studies will be conducted to suggest to coaches drills and exercises to improve
blocking abilities.
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